diff --git a/src/db/db/dbAsIfFlatRegion.cc b/src/db/db/dbAsIfFlatRegion.cc
index f05e76fcd..339af0235 100644
--- a/src/db/db/dbAsIfFlatRegion.cc
+++ b/src/db/db/dbAsIfFlatRegion.cc
@@ -1879,7 +1879,7 @@ AsIfFlatRegion::add (const Region &other) const
 }
 
 static void
-deliver_shapes_of_nets_recursive (db::Shapes &out, const db::Circuit *circuit, const LayoutToNetlist *l2n, const db::Region *of_layer, NetPropertyMode prop_mode, const tl::Variant &net_prop_name, const db::ICplxTrans &tr, const std::set<const db::Net *> *net_filter)
+deliver_shapes_of_nets_recursive (db::Shapes &out, const db::Circuit *circuit, const LayoutToNetlist *l2n, unsigned int lid, NetPropertyMode prop_mode, const tl::Variant &net_prop_name, const db::ICplxTrans &tr, const std::set<const db::Net *> *net_filter)
 {
   db::CplxTrans dbu_trans (l2n->internal_layout ()->dbu ());
   auto dbu_trans_inv = dbu_trans.inverted ();
@@ -1888,14 +1888,14 @@ deliver_shapes_of_nets_recursive (db::Shapes &out, const db::Circuit *circuit, c
 
     if (! net_filter || net_filter->find (n.operator-> ()) != net_filter->end ()) {
       db::properties_id_type prop_id = db::NetBuilder::make_netname_propid (prop_mode, net_prop_name, *n);
-      l2n->shapes_of_net (*n, *of_layer, true, out, prop_id, tr);
+      l2n->shapes_of_net (*n, lid, true, out, prop_id, tr);
     }
 
     //  dive into subcircuits
     for (auto sc = circuit->begin_subcircuits (); sc != circuit->end_subcircuits (); ++sc) {
       const db::Circuit *circuit_ref = sc->circuit_ref ();
       db::ICplxTrans tr_ref = tr * (dbu_trans_inv * sc->trans () * dbu_trans);
-      deliver_shapes_of_nets_recursive (out, circuit_ref, l2n, of_layer, prop_mode, net_prop_name, tr_ref, net_filter);
+      deliver_shapes_of_nets_recursive (out, circuit_ref, l2n, lid, prop_mode, net_prop_name, tr_ref, net_filter);
     }
 
   }
@@ -1909,9 +1909,9 @@ AsIfFlatRegion::nets (LayoutToNetlist *l2n, NetPropertyMode prop_mode, const tl:
   }
 
   std::unique_ptr<db::FlatRegion> result (new db::FlatRegion ());
-  std::unique_ptr<db::Region> region_for_layer (l2n->layer_by_original (this));
+  tl::optional<unsigned int> li = l2n->layer_by_original (this);
 
-  if (! region_for_layer) {
+  if (! li.has_value ()) {
     throw tl::Exception (tl::to_string (tr ("The given layer is not an original layer used in netlist extraction")));
   }
 
@@ -1927,7 +1927,7 @@ AsIfFlatRegion::nets (LayoutToNetlist *l2n, NetPropertyMode prop_mode, const tl:
     net_filter_set.insert (net_filter->begin (), net_filter->end ());
   }
 
-  deliver_shapes_of_nets_recursive (result->raw_polygons (), top_circuit, l2n, region_for_layer.get (), prop_mode, net_prop_name, db::ICplxTrans (), net_filter ? &net_filter_set : 0);
+  deliver_shapes_of_nets_recursive (result->raw_polygons (), top_circuit, l2n, li.value (), prop_mode, net_prop_name, db::ICplxTrans (), net_filter ? &net_filter_set : 0);
 
   return result.release ();
 }
diff --git a/src/db/db/dbDeepRegion.cc b/src/db/db/dbDeepRegion.cc
index 3bce3d9f0..a86e2ef4a 100644
--- a/src/db/db/dbDeepRegion.cc
+++ b/src/db/db/dbDeepRegion.cc
@@ -757,13 +757,13 @@ DeepRegion::nets (LayoutToNetlist *l2n, NetPropertyMode prop_mode, const tl::Var
 
   DeepLayer result = deep_layer ().derived ();
 
-  std::unique_ptr<db::Region> region_for_layer (l2n->layer_by_original (this));
-  if (! region_for_layer) {
+  tl::optional<unsigned int> li = l2n->layer_by_original (this);
+  if (! li.has_value ()) {
     throw tl::Exception (tl::to_string (tr ("The given layer is not an original layer used in netlist extraction")));
   }
 
-  std::map<unsigned int, const db::Region *> lmap;
-  lmap.insert (std::make_pair (result.layer (), region_for_layer.get ()));
+  std::map<unsigned int, unsigned int> lmap;
+  lmap.insert (std::make_pair (result.layer (), li.value ()));
 
   net_builder.build_nets (nets, lmap, prop_mode, net_prop_name);
 
diff --git a/src/db/db/dbLayoutToNetlist.cc b/src/db/db/dbLayoutToNetlist.cc
index 802133935..3c5e06d0c 100644
--- a/src/db/db/dbLayoutToNetlist.cc
+++ b/src/db/db/dbLayoutToNetlist.cc
@@ -93,7 +93,7 @@ LayoutToNetlist::LayoutToNetlist ()
 LayoutToNetlist::~LayoutToNetlist ()
 {
   //  NOTE: do this in this order because of unregistration of the layers
-  m_named_regions.clear ();
+  m_named_dls.clear ();
   m_dlrefs.clear ();
   mp_internal_dss.reset (0);
   mp_netlist.reset (0);
@@ -175,6 +175,16 @@ db::Region *LayoutToNetlist::make_layer (unsigned int layer_index, const std::st
   return region.release ();
 }
 
+db::Texts *LayoutToNetlist::make_text_layer (const std::string &n)
+{
+  db::RecursiveShapeIterator si (m_iter);
+  si.shape_flags (db::ShapeIterator::Nothing);
+
+  std::unique_ptr <db::Texts> texts (new db::Texts (si, dss ()));
+  register_layer (*texts, n);
+  return texts.release ();
+}
+
 db::Texts *LayoutToNetlist::make_text_layer (unsigned int layer_index, const std::string &n)
 {
   db::RecursiveShapeIterator si (m_iter);
@@ -190,7 +200,7 @@ db::Region *LayoutToNetlist::make_polygon_layer (unsigned int layer_index, const
 {
   db::RecursiveShapeIterator si (m_iter);
   si.set_layer (layer_index);
-  si.shape_flags (db::ShapeIterator::Paths | db::ShapeIterator::Polygons | db::ShapeIterator::Boxes);
+  si.shape_flags (db::ShapeIterator::Regions);
 
   std::unique_ptr <db::Region> region (new db::Region (si, dss ()));
   register_layer (*region, n);
@@ -850,10 +860,10 @@ void LayoutToNetlist::mem_stat (MemStatistics *stat, MemStatistics::purpose_t pu
   db::mem_stat (stat, purpose, cat, m_net_clusters, true, (void *) this);
   db::mem_stat (stat, purpose, cat, mp_netlist, true, (void *) this);
   db::mem_stat (stat, purpose, cat, m_dlrefs, true, (void *) this);
-  db::mem_stat (stat, purpose, cat, m_named_regions, true, (void *) this);
+  db::mem_stat (stat, purpose, cat, m_named_dls, true, (void *) this);
   db::mem_stat (stat, purpose, cat, m_name_of_layer, true, (void *) this);
-  db::mem_stat (stat, purpose, cat, m_region_by_original, true, (void *) this);
-  db::mem_stat (stat, purpose, cat, m_region_of_layer, true, (void *) this);
+  db::mem_stat (stat, purpose, cat, m_dl_by_original, true, (void *) this);
+  db::mem_stat (stat, purpose, cat, m_dl_of_layer, true, (void *) this);
   db::mem_stat (stat, purpose, cat, m_joined_net_names, true, (void *) this);
   db::mem_stat (stat, purpose, cat, m_joined_net_names_per_cell, true, (void *) this);
   db::mem_stat (stat, purpose, cat, m_joined_nets, true, (void *) this);
@@ -899,6 +909,26 @@ db::Cell *LayoutToNetlist::internal_top_cell ()
   return &dss ().initial_cell (m_layout_index);
 }
 
+const db::Layout *LayoutToNetlist::original_layout () const
+{
+  return m_iter.layout ();
+}
+
+const db::Cell *LayoutToNetlist::original_top_cell () const
+{
+  return m_iter.top_cell ();
+}
+
+db::Layout *LayoutToNetlist::original_layout ()
+{
+  return const_cast<db::Layout *> (m_iter.layout ());
+}
+
+db::Cell *LayoutToNetlist::original_top_cell ()
+{
+  return const_cast<db::Cell *> (m_iter.top_cell ());
+}
+
 void LayoutToNetlist::ensure_layout () const
 {
   if (! dss ().is_valid_layout_index (m_layout_index)) {
@@ -927,7 +957,7 @@ std::string LayoutToNetlist::make_new_name (const std::string &stem)
     name += std::string ("$");
     name += tl::to_string (n - m);
 
-    if (m_named_regions.find (name) == m_named_regions.end ()) {
+    if (m_named_dls.find (name) == m_named_dls.end ()) {
       n -= m;
     }
 
@@ -948,39 +978,69 @@ std::string LayoutToNetlist::name (unsigned int l) const
 
 db::Region *LayoutToNetlist::layer_by_name (const std::string &name)
 {
-  std::map<std::string, db::DeepLayer>::const_iterator l = m_named_regions.find (name);
-  if (l == m_named_regions.end ()) {
+  std::map<std::string, db::DeepLayer>::const_iterator l = m_named_dls.find (name);
+  if (l == m_named_dls.end ()) {
     return 0;
   } else {
     return new db::Region (new db::DeepRegion (l->second));
   }
 }
 
+db::Texts *LayoutToNetlist::texts_by_name (const std::string &name)
+{
+  std::map<std::string, db::DeepLayer>::const_iterator l = m_named_dls.find (name);
+  if (l == m_named_dls.end ()) {
+    return 0;
+  } else {
+    return new db::Texts (new db::DeepTexts (l->second));
+  }
+}
+
+tl::optional<unsigned int> LayoutToNetlist::layer_index_by_name (const std::string &name) const
+{
+  std::map<std::string, db::DeepLayer>::const_iterator l = m_named_dls.find (name);
+  if (l == m_named_dls.end ()) {
+    return tl::optional<unsigned int> ();
+  } else {
+    return tl::optional<unsigned int> (l->second.layer ());
+  }
+}
+
 db::Region *LayoutToNetlist::layer_by_index (unsigned int index)
 {
-  auto n = m_region_of_layer.find (index);
-  if (n == m_region_of_layer.end ()) {
+  auto n = m_dl_of_layer.find (index);
+  if (n == m_dl_of_layer.end ()) {
     return 0;
   } else {
     return new db::Region (new db::DeepRegion (n->second));
   }
 }
 
-db::Region *LayoutToNetlist::layer_by_original (const ShapeCollectionDelegateBase *original_delegate)
+db::Texts *LayoutToNetlist::texts_by_index (unsigned int index)
 {
-  auto n = m_region_by_original.find (tl::id_of (original_delegate));
-  if (n == m_region_by_original.end ()) {
+  auto n = m_dl_of_layer.find (index);
+  if (n == m_dl_of_layer.end ()) {
+    return 0;
+  } else {
+    return new db::Texts (new db::DeepTexts (n->second));
+  }
+}
+
+tl::optional<unsigned int> LayoutToNetlist::layer_by_original (const ShapeCollectionDelegateBase *original_delegate)
+{
+  auto n = m_dl_by_original.find (tl::id_of (original_delegate));
+  if (n == m_dl_by_original.end ()) {
 
     DeepShapeCollectionDelegateBase *dl = const_cast<ShapeCollectionDelegateBase *> (original_delegate)->deep ();
     if (dl && dl->deep_layer ().store () == mp_dss.get ()) {
       //  implicitly original because the collection is inside our DSS
-      return new db::Region (new db::DeepRegion (dl->deep_layer ()));
+      return tl::optional<unsigned int> (dl->deep_layer ().layer ());
     } else {
-      return 0;
+      return tl::optional<unsigned int> ();
     }
 
   } else {
-    return new db::Region (new db::DeepRegion (n->second));
+    return tl::optional<unsigned int> (n->second.layer ());
   }
 }
 
@@ -1009,11 +1069,11 @@ std::string LayoutToNetlist::name (const ShapeCollection &coll) const
 
 unsigned int LayoutToNetlist::register_layer (const ShapeCollection &collection, const std::string &n_in)
 {
-  if (m_region_by_original.find (tl::id_of (collection.get_delegate ())) != m_region_by_original.end ()) {
+  if (m_dl_by_original.find (tl::id_of (collection.get_delegate ())) != m_dl_by_original.end ()) {
     throw tl::Exception (tl::to_string (tr ("The layer is already registered")));
   }
 
-  if (! n_in.empty () && m_named_regions.find (n_in) != m_named_regions.end ()) {
+  if (! n_in.empty () && m_named_dls.find (n_in) != m_named_dls.end ()) {
     throw tl::Exception (tl::to_string (tr ("Layer name is already used: ")) + n_in);
   }
 
@@ -1043,9 +1103,9 @@ unsigned int LayoutToNetlist::register_layer (const ShapeCollection &collection,
 
   unsigned int layer = dl.layer ();
 
-  m_region_by_original [tl::id_of (collection.get_delegate ())] = dl;
-  m_region_of_layer [layer] = dl;
-  m_named_regions [n] = dl;
+  m_dl_by_original [tl::id_of (collection.get_delegate ())] = dl;
+  m_dl_of_layer [layer] = dl;
+  m_named_dls [n] = dl;
   m_name_of_layer [layer] = n;
 
   return layer;
@@ -1075,7 +1135,7 @@ bool LayoutToNetlist::is_persisted_impl (const db::ShapeCollection &coll) const
     return true;
   } else {
     //  explicitly persisted through "register"
-    return m_region_by_original.find (tl::id_of (coll.get_delegate ())) != m_region_by_original.end ();
+    return m_dl_by_original.find (tl::id_of (coll.get_delegate ())) != m_dl_by_original.end ();
   }
 }
 
@@ -1126,10 +1186,10 @@ db::CellMapping LayoutToNetlist::const_cell_mapping_into (const db::Layout &layo
   return cm;
 }
 
-std::map<unsigned int, const db::Region *>
+std::map<unsigned int, unsigned int>
 LayoutToNetlist::create_layermap (db::Layout &target_layout, int ln) const
 {
-  std::map<unsigned int, const db::Region *> lm;
+  std::map<unsigned int, unsigned int> lm;
   if (! internal_layout ()) {
     return lm;
   }
@@ -1144,13 +1204,13 @@ LayoutToNetlist::create_layermap (db::Layout &target_layout, int ln) const
 
   for (std::set<unsigned int>::const_iterator l = layers_to_copy.begin (); l != layers_to_copy.end (); ++l) {
     const db::LayerProperties &lp = source_layout.get_properties (*l);
-    unsigned int tl;
     if (! lp.is_null ()) {
-      tl = target_layout.insert_layer (lp);
-    } else {
-      tl = target_layout.insert_layer (db::LayerProperties (ln++, 0, name (*l)));
+      unsigned int tl = target_layout.insert_layer (lp);
+      lm.insert (std::make_pair (tl, *l));
+    } else if (ln >= 0) {
+      unsigned int tl = target_layout.insert_layer (db::LayerProperties (ln++, 0, name (*l)));
+      lm.insert (std::make_pair (tl, *l));
     }
-    lm.insert (std::make_pair (tl, const_cast<LayoutToNetlist *> (this)->layer_by_index (*l)));
   }
 
   return lm;
@@ -1179,16 +1239,43 @@ static bool deliver_shape (const db::NetShape &, StopOnFirst, const Tr &, db::pr
 }
 
 template <class Tr>
-static bool deliver_shape (const db::NetShape &s, db::Region &region, const Tr &tr, db::properties_id_type /*propid*/)
+static bool deliver_shape (const db::NetShape &s, db::Region &region, const Tr &tr, db::properties_id_type propid)
 {
   if (s.type () == db::NetShape::Polygon) {
 
     db::PolygonRef pr = s.polygon_ref ();
 
     if (pr.obj ().is_box ()) {
-      region.insert (pr.obj ().box ().transformed (pr.trans ()).transformed (tr));
+      if (propid) {
+        region.insert (db::BoxWithProperties (pr.obj ().box ().transformed (pr.trans ()).transformed (tr), propid));
+      } else {
+        region.insert (pr.obj ().box ().transformed (pr.trans ()).transformed (tr));
+      }
     } else {
-      region.insert (pr.obj ().transformed (pr.trans ()).transformed (tr));
+      if (propid) {
+        region.insert (db::PolygonWithProperties (pr.obj ().transformed (pr.trans ()).transformed (tr), propid));
+      } else {
+        region.insert (pr.obj ().transformed (pr.trans ()).transformed (tr));
+      }
+    }
+
+  }
+
+  return true;
+}
+
+template <class Tr>
+static bool deliver_shape (const db::NetShape &s, db::Texts &texts, const Tr &tr, db::properties_id_type propid)
+{
+  if (s.type () == db::NetShape::Text) {
+
+    db::TextRef pr = s.text_ref ();
+
+    db::Text text (pr.obj ().transformed (pr.trans ()).transformed (tr));
+    if (propid) {
+      texts.insert (db::TextWithProperties (text, propid));
+    } else {
+      texts.insert (text);
     }
 
   }
@@ -1407,9 +1494,14 @@ LayoutToNetlist::shapes_of_terminal (const db::NetTerminalRef &terminal, const d
   return result;
 }
 
-void LayoutToNetlist::shapes_of_net (const db::Net &net, const db::Region &of_layer, bool recursive, db::Shapes &to, db::properties_id_type propid, const ICplxTrans &trans) const
+void LayoutToNetlist::shapes_of_net (const db::Net &net, const db::ShapeCollection &of_layer, bool recursive, db::Shapes &to, db::properties_id_type propid, const ICplxTrans &trans) const
 {
   unsigned int lid = layer_of (of_layer);
+  shapes_of_net (net, lid, recursive, to, propid, trans);
+}
+
+void LayoutToNetlist::shapes_of_net (const db::Net &net, unsigned int lid, bool recursive, db::Shapes &to, db::properties_id_type propid, const ICplxTrans &trans) const
+{
   const db::Circuit *circuit = net.circuit ();
   tl_assert (circuit != 0);
 
@@ -1419,14 +1511,14 @@ void LayoutToNetlist::shapes_of_net (const db::Net &net, const db::Region &of_la
   deliver_shapes_of_net (recursive, mp_netlist.get (), m_net_clusters, circuit->cell_index (), net.cluster_id (), lmap, trans, propid);
 }
 
-db::Region *LayoutToNetlist::shapes_of_net (const db::Net &net, const db::Region &of_layer, bool recursive, const db::ICplxTrans &trans) const
+template<class Coll>
+Coll *LayoutToNetlist::shapes_of_net_with_layer_index (const db::Net &net, unsigned int lid, bool recursive, const db::ICplxTrans &trans) const
 {
-  unsigned int lid = layer_of (of_layer);
   const db::Circuit *circuit = net.circuit ();
   tl_assert (circuit != 0);
 
-  std::unique_ptr<db::Region> res (new db::Region ());
-  std::map<unsigned int, db::Region *> lmap;
+  std::unique_ptr<Coll> res (new Coll ());
+  std::map<unsigned int, Coll *> lmap;
   lmap [lid] = res.get ();
 
   deliver_shapes_of_net (recursive, mp_netlist.get (), m_net_clusters, circuit->cell_index (), net.cluster_id (), lmap, trans, 0);
@@ -1434,8 +1526,14 @@ db::Region *LayoutToNetlist::shapes_of_net (const db::Net &net, const db::Region
   return res.release ();
 }
 
+//  explicit instantiations
+template
+DB_PUBLIC db::Region *LayoutToNetlist::shapes_of_net_with_layer_index<db::Region> (const db::Net &net, unsigned int lid, bool recursive, const db::ICplxTrans &trans) const;
+template
+DB_PUBLIC db::Texts *LayoutToNetlist::shapes_of_net_with_layer_index<db::Texts> (const db::Net &net, unsigned int lid, bool recursive, const db::ICplxTrans &trans) const;
+
 void
-LayoutToNetlist::build_net (const db::Net &net, db::Layout &target, db::Cell &target_cell, const std::map<unsigned int, const db::Region *> &lmap, NetPropertyMode net_prop_mode, const tl::Variant &netname_prop, BuildNetHierarchyMode hier_mode, const char *cell_name_prefix, const char *device_cell_name_prefix) const
+LayoutToNetlist::build_net (const db::Net &net, db::Layout &target, db::Cell &target_cell, const std::map<unsigned int, unsigned int> &lmap, NetPropertyMode net_prop_mode, const tl::Variant &netname_prop, BuildNetHierarchyMode hier_mode, const char *cell_name_prefix, const char *device_cell_name_prefix) const
 {
   NetBuilder builder (&target, this);
   builder.set_hier_mode (hier_mode);
@@ -1446,7 +1544,7 @@ LayoutToNetlist::build_net (const db::Net &net, db::Layout &target, db::Cell &ta
 }
 
 void
-LayoutToNetlist::build_all_nets (const db::CellMapping &cmap, db::Layout &target, const std::map<unsigned int, const db::Region *> &lmap, const char *net_cell_name_prefix, NetPropertyMode net_prop_mode, const tl::Variant &netname_prop, BuildNetHierarchyMode hier_mode, const char *circuit_cell_name_prefix, const char *device_cell_name_prefix) const
+LayoutToNetlist::build_all_nets (const db::CellMapping &cmap, db::Layout &target, const std::map<unsigned int, unsigned int> &lmap, const char *net_cell_name_prefix, NetPropertyMode net_prop_mode, const tl::Variant &netname_prop, BuildNetHierarchyMode hier_mode, const char *circuit_cell_name_prefix, const char *device_cell_name_prefix) const
 {
   NetBuilder builder (&target, cmap, this);
   builder.set_hier_mode (hier_mode);
@@ -1458,7 +1556,7 @@ LayoutToNetlist::build_all_nets (const db::CellMapping &cmap, db::Layout &target
 }
 
 void
-LayoutToNetlist::build_nets (const std::vector<const db::Net *> *nets, const db::CellMapping &cmap, db::Layout &target, const std::map<unsigned int, const db::Region *> &lmap, const char *net_cell_name_prefix, NetPropertyMode net_prop_mode, const tl::Variant &netname_prop, BuildNetHierarchyMode hier_mode, const char *circuit_cell_name_prefix, const char *device_cell_name_prefix) const
+LayoutToNetlist::build_nets (const std::vector<const db::Net *> *nets, const db::CellMapping &cmap, db::Layout &target, const std::map<unsigned int, unsigned int> &lmap, const char *net_cell_name_prefix, NetPropertyMode net_prop_mode, const tl::Variant &netname_prop, BuildNetHierarchyMode hier_mode, const char *circuit_cell_name_prefix, const char *device_cell_name_prefix) const
 {
   NetBuilder builder (&target, cmap, this);
   builder.set_hier_mode (hier_mode);
@@ -2152,7 +2250,7 @@ NetBuilder::prepare_build_nets () const
 }
 
 void
-NetBuilder::build_net (db::Cell &target_cell, const db::Net &net, const std::map<unsigned int, const db::Region *> &lmap, NetPropertyMode net_prop_mode, const tl::Variant &netname_prop) const
+NetBuilder::build_net (db::Cell &target_cell, const db::Net &net, const std::map<unsigned int, unsigned int> &lmap, NetPropertyMode net_prop_mode, const tl::Variant &netname_prop) const
 {
   prepare_build_nets ();
 
@@ -2163,13 +2261,13 @@ NetBuilder::build_net (db::Cell &target_cell, const db::Net &net, const std::map
 }
 
 void
-NetBuilder::build_all_nets (const std::map<unsigned int, const db::Region *> &lmap, NetPropertyMode net_prop_mode, const tl::Variant &netname_prop) const
+NetBuilder::build_all_nets (const std::map<unsigned int, unsigned int> &lmap, NetPropertyMode net_prop_mode, const tl::Variant &netname_prop) const
 {
   build_nets (0, lmap, net_prop_mode, netname_prop);
 }
 
 void
-NetBuilder::build_nets (const std::vector<const Net *> *nets, const std::map<unsigned int, const db::Region *> &lmap, NetPropertyMode prop_mode, const tl::Variant &netname_prop) const
+NetBuilder::build_nets (const std::vector<const Net *> *nets, const std::map<unsigned int, unsigned int> &lmap, NetPropertyMode prop_mode, const tl::Variant &netname_prop) const
 {
   prepare_build_nets ();
 
@@ -2239,7 +2337,7 @@ NetBuilder::build_nets (const std::vector<const Net *> *nets, const std::map<uns
 }
 
 void
-NetBuilder::build_net_rec (const db::Net &net, db::Cell &target_cell, const std::map<unsigned int, const db::Region *> &lmap, const std::string &add_net_cell_name_prefix, db::properties_id_type netname_propid, const db::ICplxTrans &tr) const
+NetBuilder::build_net_rec (const db::Net &net, db::Cell &target_cell, const std::map<unsigned int, unsigned int> &lmap, const std::string &add_net_cell_name_prefix, db::properties_id_type netname_propid, const db::ICplxTrans &tr) const
 {
   const db::Circuit *circuit = net.circuit ();
   tl_assert (circuit != 0);
@@ -2248,7 +2346,7 @@ NetBuilder::build_net_rec (const db::Net &net, db::Cell &target_cell, const std:
 }
 
 void
-NetBuilder::build_net_rec (db::cell_index_type ci, size_t cid, db::Cell &tc, const std::map<unsigned int, const db::Region *> &lmap, const db::Net *net, const std::string &add_net_cell_name_prefix, db::properties_id_type netname_propid, const db::ICplxTrans &tr) const
+NetBuilder::build_net_rec (db::cell_index_type ci, size_t cid, db::Cell &tc, const std::map<unsigned int, unsigned int> &lmap, const db::Net *net, const std::string &add_net_cell_name_prefix, db::properties_id_type netname_propid, const db::ICplxTrans &tr) const
 {
   db::Cell *target_cell = &tc;
 
@@ -2261,9 +2359,9 @@ NetBuilder::build_net_rec (db::cell_index_type ci, size_t cid, db::Cell &tc, con
 
       StopOnFirst sof;
       std::map<unsigned int, StopOnFirst *> sof_lmap;
-      for (std::map<unsigned int, const db::Region *>::const_iterator l = lmap.begin (); l != lmap.end (); ++l) {
+      for (std::map<unsigned int, unsigned int>::const_iterator l = lmap.begin (); l != lmap.end (); ++l) {
         if (l->second) {
-          sof_lmap.insert (std::make_pair (mp_source->layer_of (*l->second), &sof));
+          sof_lmap.insert (std::make_pair (l->second, &sof));
         }
       }
 
@@ -2283,9 +2381,9 @@ NetBuilder::build_net_rec (db::cell_index_type ci, size_t cid, db::Cell &tc, con
   }
 
   std::map<unsigned int, db::Shapes *> target_lmap;
-  for (std::map<unsigned int, const db::Region *>::const_iterator l = lmap.begin (); l != lmap.end (); ++l) {
+  for (std::map<unsigned int, unsigned int>::const_iterator l = lmap.begin (); l != lmap.end (); ++l) {
     if (l->second) {
-      target_lmap.insert (std::make_pair (mp_source->layer_of (*l->second), &target_cell->shapes (l->first)));
+      target_lmap.insert (std::make_pair (l->second, &target_cell->shapes (l->first)));
     }
   }
 
@@ -2354,7 +2452,7 @@ NetBuilder::build_net_rec (db::cell_index_type ci, size_t cid, db::Cell &tc, con
 }
 
 void
-NetBuilder::build_net_rec (const db::Net &net, db::cell_index_type circuit_cell, const std::map<unsigned int, const db::Region *> &lmap, const std::string &add_net_cell_name_prefix, db::properties_id_type netname_propid, const ICplxTrans &tr) const
+NetBuilder::build_net_rec (const db::Net &net, db::cell_index_type circuit_cell, const std::map<unsigned int, unsigned int> &lmap, const std::string &add_net_cell_name_prefix, db::properties_id_type netname_propid, const ICplxTrans &tr) const
 {
   if (! m_cmap.has_mapping (circuit_cell)) {
 
diff --git a/src/db/db/dbLayoutToNetlist.h b/src/db/db/dbLayoutToNetlist.h
index a76f44784..4b35c7914 100644
--- a/src/db/db/dbLayoutToNetlist.h
+++ b/src/db/db/dbLayoutToNetlist.h
@@ -30,6 +30,7 @@
 #include "dbLayoutToNetlistEnums.h"
 #include "dbLog.h"
 #include "tlGlobPattern.h"
+#include "tlOptional.h"
 
 namespace db
 {
@@ -355,6 +356,13 @@ public:
     return is_persisted_impl (coll);
   }
 
+  /**
+   *  @brief Gets the layer index from a name
+   *
+   *  If the name is not valid, the optional value will not be set.
+   */
+  tl::optional<unsigned int> layer_index_by_name (const std::string &name) const;
+
   /**
    *  @brief Gets the region (layer) with the given name
    *  If the name is not valid, this method returns 0. Otherwise it
@@ -363,20 +371,34 @@ public:
    */
   db::Region *layer_by_name (const std::string &name);
 
+  /**
+   *  @brief Gets the texts (layer) with the given name
+   *  If the name is not valid, this method returns 0. Otherwise it
+   *  will return a new'd Texts object referencing the layer with
+   *  the given name. It must be deleted by the caller.
+   */
+  db::Texts *texts_by_name (const std::string &name);
+
   /**
    *  @brief Gets the region (layer) by index
    *  If the index is not valid, this method returns 0. Otherwise it
    *  will return a new'd Region object referencing the layer with
    *  the given name. It must be deleted by the caller.
-   *  Only named layers are managed by LayoutToNetlist and can
-   *  be retrieved with this method.
    */
   db::Region *layer_by_index (unsigned int index);
 
+  /**
+   *  @brief Gets the texts (layer) by index
+   *  If the index is not valid, this method returns 0. Otherwise it
+   *  will return a new'd Texts object referencing the layer with
+   *  the given name. It must be deleted by the caller.
+   */
+  db::Texts *texts_by_index (unsigned int index);
+
   /**
    *  @brief Gets the internal layer from the original layer
    */
-  db::Region *layer_by_original (const ShapeCollection &original_layer)
+  tl::optional<unsigned int> layer_by_original (const ShapeCollection &original_layer)
   {
     return layer_by_original (original_layer.get_delegate ());
   }
@@ -385,7 +407,7 @@ public:
    *  @brief Gets the layer from the original layer's delegate
    *  Returns 0 if the original layer was not registered as an input_layer.
    */
-  db::Region *layer_by_original (const ShapeCollectionDelegateBase *original_delegate);
+  tl::optional<unsigned int> layer_by_original (const ShapeCollectionDelegateBase *original_delegate);
 
   /**
    *  @brief Iterates over the layer indexes and names managed by this object (begin)
@@ -409,6 +431,12 @@ public:
    */
   db::Region *make_layer (const std::string &name = std::string ());
 
+  /**
+   *  @brief Creates a new empty texts collection
+   *  This method returns a new'd object which must be deleted by the caller.
+   */
+  db::Texts *make_text_layer (const std::string &name = std::string ());
+
   /**
    *  @brief Creates a new region representing an original layer
    *  "layer_index" is the layer index of the desired layer in the original layout.
@@ -746,6 +774,26 @@ public:
    */
   db::Cell *internal_top_cell ();
 
+  /**
+   *  @brief Gets the original layout
+   */
+  const db::Layout *original_layout () const;
+
+  /**
+   *  @brief Gets the original top cell
+   */
+  const db::Cell *original_top_cell () const;
+
+  /**
+   *  @brief Gets the original layout (non-const version)
+   */
+  db::Layout *original_layout ();
+
+  /**
+   *  @brief Gets the original top cell (non-const version)
+   */
+  db::Cell *original_top_cell ();
+
   /**
    *  @brief Gets the connectivity object
    */
@@ -795,8 +843,9 @@ public:
    *  original layers as kept inside the LayoutToNetlist database.
    *  It will return a layer mapping table suitable for use with build_all_nets, build_nets etc.
    *  Layers without original layer information will be given layer numbers ln, ln+1 etc.
+   *  unless ln is < 0, in which case such layers will not be produced.
    */
-  std::map<unsigned int, const db::Region *> create_layermap (db::Layout &target_layout, int ln) const;
+  std::map<unsigned int, unsigned int> create_layermap (db::Layout &target_layout, int ln = -1) const;
 
   /**
    *  @brief gets the netlist extracted (0 if no extraction happened yet)
@@ -855,7 +904,21 @@ public:
   std::map<unsigned int, db::Region> shapes_of_terminal (const db::NetTerminalRef &terminal, const db::ICplxTrans &trans = db::ICplxTrans ()) const;
 
   /**
-   *  @brief Returns all shapes of a specific net and layer.
+   *  @brief Returns all polygons or texts of a specific net and layer.
+   *
+   *  If "recursive" is true, the returned region will contain the shapes of
+   *  all subcircuits too.
+   *
+   *  This version takes a layer index.
+   *
+   *  This methods returns a new'd Coll object. It's the responsibility of the caller
+   *  to delete this object.
+   */
+  template <class Coll>
+  Coll *shapes_of_net_with_layer_index (const db::Net &net, unsigned int lid, bool recursive, const db::ICplxTrans &trans = db::ICplxTrans ()) const;
+
+  /**
+   *  @brief Returns all polygons of a specific net and layer.
    *
    *  If "recursive" is true, the returned region will contain the shapes of
    *  all subcircuits too.
@@ -863,7 +926,24 @@ public:
    *  This methods returns a new'd Region. It's the responsibility of the caller
    *  to delete this object.
    */
-  db::Region *shapes_of_net (const db::Net &net, const db::Region &of_layer, bool recursive, const db::ICplxTrans &trans = db::ICplxTrans ()) const;
+  db::Region *shapes_of_net (const db::Net &net, const db::Region &of_layer, bool recursive, const db::ICplxTrans &trans = db::ICplxTrans ()) const
+  {
+    return shapes_of_net_with_layer_index<db::Region> (net, layer_of (of_layer), recursive, trans);
+  }
+
+  /**
+   *  @brief Returns all texts of a specific net and layer.
+   *
+   *  If "recursive" is true, the returned region will contain the shapes of
+   *  all subcircuits too.
+   *
+   *  This methods returns a new'd Texts object. It's the responsibility of the caller
+   *  to delete this object.
+   */
+  db::Texts *shapes_of_net (const db::Net &net, const db::Texts &of_layer, bool recursive, const db::ICplxTrans &trans = db::ICplxTrans ()) const
+  {
+    return shapes_of_net_with_layer_index<db::Texts> (net, layer_of (of_layer), recursive, trans);
+  }
 
   /**
    *  @brief Delivers all shapes of a specific net and layer to the given Shapes container.
@@ -876,7 +956,14 @@ public:
    *
    *  propid is an optional properties ID which is attached to the shapes if not 0.
    */
-  void shapes_of_net (const db::Net &net, const db::Region &of_layer, bool recursive, db::Shapes &to, properties_id_type propid = 0, const db::ICplxTrans &trans = db::ICplxTrans ()) const;
+  void shapes_of_net (const db::Net &net, const db::ShapeCollection &of_layer, bool recursive, db::Shapes &to, properties_id_type propid = 0, const db::ICplxTrans &trans = db::ICplxTrans ()) const;
+
+  /**
+   *  @brief Delivers all shapes of a specific net and layer to the given Shapes container.
+   *
+   *  This version takes a layer index for the layer
+   */
+  void shapes_of_net (const db::Net &net, unsigned int lid, bool recursive, db::Shapes &to, properties_id_type propid = 0, const db::ICplxTrans &trans = db::ICplxTrans ()) const;
 
   /**
    *  @brief Builds a net representation in the given layout and cell
@@ -909,7 +996,7 @@ public:
    *  @param cell_name_prefix Chooses recursive mode if non-null
    *  @param device_cell_name_prefix See above
    */
-  void build_net (const db::Net &net, db::Layout &target, db::Cell &target_cell, const std::map<unsigned int, const db::Region *> &lmap, NetPropertyMode prop_mode, const tl::Variant &netname_prop, BuildNetHierarchyMode hier_mode, const char *cell_name_prefix, const char *device_cell_name_prefix) const;
+  void build_net (const db::Net &net, db::Layout &target, db::Cell &target_cell, const std::map<unsigned int, unsigned int> &lmap, NetPropertyMode prop_mode, const tl::Variant &netname_prop, BuildNetHierarchyMode hier_mode, const char *cell_name_prefix, const char *device_cell_name_prefix) const;
 
   /**
    *  @brief Builds a full hierarchical representation of the nets
@@ -949,12 +1036,12 @@ public:
    *  @param circuit_cell_name_prefix See method description
    *  @param device_cell_name_prefix See above
    */
-  void build_all_nets (const db::CellMapping &cmap, db::Layout &target, const std::map<unsigned int, const db::Region *> &lmap, const char *net_cell_name_prefix, NetPropertyMode prop_mode, const tl::Variant &netname_prop, BuildNetHierarchyMode hier_mode, const char *circuit_cell_name_prefix, const char *device_cell_name_prefix) const;
+  void build_all_nets (const db::CellMapping &cmap, db::Layout &target, const std::map<unsigned int, unsigned int> &lmap, const char *net_cell_name_prefix, NetPropertyMode prop_mode, const tl::Variant &netname_prop, BuildNetHierarchyMode hier_mode, const char *circuit_cell_name_prefix, const char *device_cell_name_prefix) const;
 
   /**
    *  @brief Like build_all_nets, but with the ability to select some nets
    */
-  void build_nets (const std::vector<const Net *> *nets, const db::CellMapping &cmap, db::Layout &target, const std::map<unsigned int, const db::Region *> &lmap, const char *net_cell_name_prefix, NetPropertyMode prop_mode, const tl::Variant &netname_prop, BuildNetHierarchyMode hier_mode, const char *circuit_cell_name_prefix, const char *device_cell_name_prefix) const;
+  void build_nets (const std::vector<const Net *> *nets, const db::CellMapping &cmap, db::Layout &target, const std::map<unsigned int, unsigned int> &lmap, const char *net_cell_name_prefix, NetPropertyMode prop_mode, const tl::Variant &netname_prop, BuildNetHierarchyMode hier_mode, const char *circuit_cell_name_prefix, const char *device_cell_name_prefix) const;
 
   /**
    *  @brief Finds the net by probing a specific location on the given layer
@@ -1101,10 +1188,10 @@ private:
   db::hier_clusters<db::NetShape> m_net_clusters;
   std::unique_ptr<db::Netlist> mp_netlist;
   std::set<db::DeepLayer> m_dlrefs;
-  std::map<std::string, db::DeepLayer> m_named_regions;
+  std::map<std::string, db::DeepLayer> m_named_dls;
   std::map<unsigned int, std::string> m_name_of_layer;
-  std::map<tl::id_type, db::DeepLayer> m_region_by_original;
-  std::map<unsigned int, db::DeepLayer> m_region_of_layer;
+  std::map<tl::id_type, db::DeepLayer> m_dl_by_original;
+  std::map<unsigned int, db::DeepLayer> m_dl_of_layer;
   bool m_netlist_extracted;
   bool m_is_flat;
   double m_device_scaling;
@@ -1234,17 +1321,17 @@ public:
   /**
    *  @brief See \LayoutToNetlist for details of this function
    */
-  void build_net (db::Cell &target_cell, const db::Net &net, const std::map<unsigned int, const db::Region *> &lmap, NetPropertyMode prop_mode, const tl::Variant &netname_prop) const;
+  void build_net (db::Cell &target_cell, const db::Net &net, const std::map<unsigned int, unsigned int> &lmap, NetPropertyMode prop_mode, const tl::Variant &netname_prop) const;
 
   /**
    *  @brief See \LayoutToNetlist for details of this function
    */
-  void build_all_nets (const std::map<unsigned int, const db::Region *> &lmap, NetPropertyMode prop_mode, const tl::Variant &netname_prop) const;
+  void build_all_nets (const std::map<unsigned int, unsigned int> &lmap, NetPropertyMode prop_mode, const tl::Variant &netname_prop) const;
 
   /**
    *  @brief See \LayoutToNetlist for details of this function
    */
-  void build_nets (const std::vector<const Net *> *nets, const std::map<unsigned int, const db::Region *> &lmap, NetPropertyMode prop_mode, const tl::Variant &netname_prop) const;
+  void build_nets (const std::vector<const Net *> *nets, const std::map<unsigned int, unsigned int> &lmap, NetPropertyMode prop_mode, const tl::Variant &netname_prop) const;
 
   /**
    *  @brief A helper function to create a property ID for a given net, net property name and net property mode
@@ -1293,9 +1380,9 @@ private:
   bool m_has_device_cell_name_prefix;
   std::string m_device_cell_name_prefix;
 
-  void build_net_rec (const db::Net &net, cell_index_type circuit_cell, const std::map<unsigned int, const db::Region *> &lmap, const std::string &add_net_cell_name_prefix, db::properties_id_type netname_propid, const ICplxTrans &tr) const;
-  void build_net_rec (const db::Net &net, db::Cell &target_cell, const std::map<unsigned int, const db::Region *> &lmap, const std::string &add_net_cell_name_prefix, db::properties_id_type netname_propid, const ICplxTrans &tr) const;
-  void build_net_rec (db::cell_index_type ci, size_t cid, db::Cell &target_cell, const std::map<unsigned int, const db::Region *> &lmap, const Net *net, const std::string &add_net_cell_name_prefix, db::properties_id_type netname_propid, const ICplxTrans &tr) const;
+  void build_net_rec (const db::Net &net, cell_index_type circuit_cell, const std::map<unsigned int, unsigned int> &lmap, const std::string &add_net_cell_name_prefix, db::properties_id_type netname_propid, const ICplxTrans &tr) const;
+  void build_net_rec (const db::Net &net, db::Cell &target_cell, const std::map<unsigned int, unsigned int> &lmap, const std::string &add_net_cell_name_prefix, db::properties_id_type netname_propid, const ICplxTrans &tr) const;
+  void build_net_rec (db::cell_index_type ci, size_t cid, db::Cell &target_cell, const std::map<unsigned int, unsigned int> &lmap, const Net *net, const std::string &add_net_cell_name_prefix, db::properties_id_type netname_propid, const ICplxTrans &tr) const;
   void prepare_build_nets () const;
 
   db::Layout &target () const
diff --git a/src/db/db/gsiDeclDbLayoutToNetlist.cc b/src/db/db/gsiDeclDbLayoutToNetlist.cc
index ef9425d5b..facc04627 100644
--- a/src/db/db/gsiDeclDbLayoutToNetlist.cc
+++ b/src/db/db/gsiDeclDbLayoutToNetlist.cc
@@ -51,37 +51,93 @@ static db::LayoutToNetlist *make_l2n_flat (const std::string &topcell_name, doub
 
 static db::Layout *l2n_internal_layout (db::LayoutToNetlist *l2n)
 {
-  //  although this isn't very clean, we dare to do so as const references are pretty useless in script languages.
-  return const_cast<db::Layout *> (l2n->internal_layout ());
+  return l2n->internal_layout ();
 }
 
 static db::Cell *l2n_internal_top_cell (db::LayoutToNetlist *l2n)
 {
-  //  although this isn't very clean, we dare to do so as const references are pretty useless in script languages.
-  return const_cast<db::Cell *> (l2n->internal_top_cell ());
+  return l2n->internal_top_cell ();
 }
 
-static void build_net (const db::LayoutToNetlist *l2n, const db::Net &net, db::Layout &target, db::Cell &target_cell, const std::map<unsigned int, const db::Region *> &lmap, const tl::Variant &netname_prop, db::BuildNetHierarchyMode hier_mode, const tl::Variant &circuit_cell_name_prefix, const tl::Variant &device_cell_name_prefix)
+static db::Layout *l2n_original_layout (db::LayoutToNetlist *l2n)
+{
+  return l2n->original_layout ();
+}
+
+static db::Cell *l2n_original_top_cell (db::LayoutToNetlist *l2n)
+{
+  return l2n->original_top_cell ();
+}
+
+static tl::Variant l2n_layer_index_by_name (const db::LayoutToNetlist *l2n, const std::string &name)
+{
+  tl::optional<unsigned int> index = l2n->layer_index_by_name (name);
+  if (index.has_value ()) {
+    return tl::Variant (index.value ());
+  } else {
+    return tl::Variant ();
+  }
+}
+
+static std::map<unsigned int, unsigned int> layer_map_from_var (const db::LayoutToNetlist *l2n, db::Layout &target, const tl::Variant &lmap)
+{
+  if (lmap.is_nil ()) {
+
+    return l2n->create_layermap (target);
+
+  } else if (! lmap.is_array ()) {
+
+    throw tl::Exception (tl::to_string (tr ("'lmap' argument needs to be nil or a hash")));
+
+  } else {
+
+    std::map<unsigned int, unsigned int> res;
+
+    for (auto kv = lmap.begin_array (); kv != lmap.end_array (); ++kv) {
+      const tl::Variant &k = kv->first;
+      const tl::Variant &v = kv->second;
+      unsigned int ki = k.to_uint ();
+      unsigned int vi = 0;
+      if (v.is_user ()) {
+        if (dynamic_cast<const tl::VariantUserClass<db::Region> *> (v.user_cls ()) != 0) {
+          vi = l2n->layer_of<db::ShapeCollection> (v.to_user<db::Region> ());
+        } else if (dynamic_cast<const tl::VariantUserClass<db::Texts> *> (v.user_cls ()) != 0) {
+          vi = l2n->layer_of<db::ShapeCollection> (v.to_user<db::Texts> ());
+        } else {
+          throw tl::Exception (tl::to_string (tr ("'lmap' argument hash values need to be ints, Region or Texts objects")));
+        }
+      } else {
+        vi = v.to_uint ();
+      }
+      res.insert (std::make_pair (ki, vi));
+    }
+
+    return res;
+
+  }
+}
+
+static void build_net (const db::LayoutToNetlist *l2n, const db::Net &net, db::Layout &target, db::Cell &target_cell, const tl::Variant &lmap, const tl::Variant &netname_prop, db::BuildNetHierarchyMode hier_mode, const tl::Variant &circuit_cell_name_prefix, const tl::Variant &device_cell_name_prefix)
 {
   std::string p = circuit_cell_name_prefix.to_string ();
   std::string dp = device_cell_name_prefix.to_string ();
-  l2n->build_net (net, target, target_cell, lmap, db::NPM_AllProperties, netname_prop, hier_mode, circuit_cell_name_prefix.is_nil () ? 0 : p.c_str (), device_cell_name_prefix.is_nil () ? 0 : dp.c_str ());
+  l2n->build_net (net, target, target_cell, layer_map_from_var (l2n, target, lmap), db::NPM_AllProperties, netname_prop, hier_mode, circuit_cell_name_prefix.is_nil () ? 0 : p.c_str (), device_cell_name_prefix.is_nil () ? 0 : dp.c_str ());
 }
 
-static void build_all_nets (const db::LayoutToNetlist *l2n, const db::CellMapping &cmap, db::Layout &target, const std::map<unsigned int, const db::Region *> &lmap, const tl::Variant &net_cell_name_prefix, const tl::Variant &netname_prop, db::BuildNetHierarchyMode hier_mode, const tl::Variant &circuit_cell_name_prefix, const tl::Variant &device_cell_name_prefix)
+static void build_all_nets (const db::LayoutToNetlist *l2n, const db::CellMapping &cmap, db::Layout &target, const tl::Variant &lmap, const tl::Variant &net_cell_name_prefix, const tl::Variant &netname_prop, db::BuildNetHierarchyMode hier_mode, const tl::Variant &circuit_cell_name_prefix, const tl::Variant &device_cell_name_prefix)
 {
   std::string cp = circuit_cell_name_prefix.to_string ();
   std::string np = net_cell_name_prefix.to_string ();
   std::string dp = device_cell_name_prefix.to_string ();
-  l2n->build_all_nets (cmap, target, lmap, net_cell_name_prefix.is_nil () ? 0 : np.c_str (), db::NPM_AllProperties, netname_prop, hier_mode, circuit_cell_name_prefix.is_nil () ? 0 : cp.c_str (), device_cell_name_prefix.is_nil () ? 0 : dp.c_str ());
+  l2n->build_all_nets (cmap, target, layer_map_from_var (l2n, target, lmap), net_cell_name_prefix.is_nil () ? 0 : np.c_str (), db::NPM_AllProperties, netname_prop, hier_mode, circuit_cell_name_prefix.is_nil () ? 0 : cp.c_str (), device_cell_name_prefix.is_nil () ? 0 : dp.c_str ());
 }
 
-static void build_nets (const db::LayoutToNetlist *l2n, const std::vector<const db::Net *> &nets, const db::CellMapping &cmap, db::Layout &target, const std::map<unsigned int, const db::Region *> &lmap, const tl::Variant &net_cell_name_prefix, const tl::Variant &netname_prop, db::BuildNetHierarchyMode hier_mode, const tl::Variant &circuit_cell_name_prefix, const tl::Variant &device_cell_name_prefix)
+static void build_nets (const db::LayoutToNetlist *l2n, const std::vector<const db::Net *> &nets, const db::CellMapping &cmap, db::Layout &target, const tl::Variant &lmap, const tl::Variant &net_cell_name_prefix, const tl::Variant &netname_prop, db::BuildNetHierarchyMode hier_mode, const tl::Variant &circuit_cell_name_prefix, const tl::Variant &device_cell_name_prefix)
 {
   std::string cp = circuit_cell_name_prefix.to_string ();
   std::string np = net_cell_name_prefix.to_string ();
   std::string dp = device_cell_name_prefix.to_string ();
-  l2n->build_nets (&nets, cmap, target, lmap, net_cell_name_prefix.is_nil () ? 0 : np.c_str (), db::NPM_AllProperties, netname_prop, hier_mode, circuit_cell_name_prefix.is_nil () ? 0 : cp.c_str (), device_cell_name_prefix.is_nil () ? 0 : dp.c_str ());
+  l2n->build_nets (&nets, cmap, target, layer_map_from_var (l2n, target, lmap), net_cell_name_prefix.is_nil () ? 0 : np.c_str (), db::NPM_AllProperties, netname_prop, hier_mode, circuit_cell_name_prefix.is_nil () ? 0 : cp.c_str (), device_cell_name_prefix.is_nil () ? 0 : dp.c_str ());
 }
 
 static std::vector<std::string> l2n_layer_names (const db::LayoutToNetlist *l2n)
@@ -370,11 +426,16 @@ Class<db::LayoutToNetlist> decl_dbLayoutToNetlist ("db", "LayoutToNetlist",
     "\n"
     "This method has been introduced in version 0.29.3.\n"
   ) +
+  gsi::method_ext ("layer_index", &l2n_layer_index_by_name,
+    "@brief Gets the layer index for a given name or nil if the name is not valid.\n"
+    "\n"
+    "This method has been introduced in version 0.30."
+  ) +
   gsi::method ("layer_name", (std::string (db::LayoutToNetlist::*) (unsigned int) const) &db::LayoutToNetlist::name, gsi::arg ("l"),
     "@brief Gets the name of the given layer (by index)\n"
     "See \\layer_index for a description of the layer index.\n"
   ) +
-  gsi::method ("register", (unsigned int (db::LayoutToNetlist::*) (const db::ShapeCollection &collection, const std::string &)) &db::LayoutToNetlist::register_layer, gsi::arg ("l"), gsi::arg ("n", std::string ()),
+  gsi::method ("register", (unsigned int (db::LayoutToNetlist::*) (const db::ShapeCollection &collection, const std::string &)) &db::LayoutToNetlist::register_layer, gsi::arg ("l"), gsi::arg ("n", std::string (), "\"\""),
     "@brief Names the given layer\n"
     "@return The index of the layer registered\n"
     "'l' must be a \\Region or \\Texts object.\n"
@@ -417,18 +478,53 @@ Class<db::LayoutToNetlist> decl_dbLayoutToNetlist ("db", "LayoutToNetlist",
     "\n"
     "This method has been introduced in version 0.29.2.\n"
   ) +
-  gsi::factory ("layer_by_name", &db::LayoutToNetlist::layer_by_name, gsi::arg ("name"),
+  gsi::factory ("polygons_by_name|#layer_by_name", &db::LayoutToNetlist::layer_by_name, gsi::arg ("name"),
     "@brief Gets a layer object for the given name.\n"
     "The returned object is a new Region object representing the named layer. It will refer to a layer inside the "
     "internal layout, or more specifically inside the \\DeepShapeStorage object (see \\dss and \\internal_layout).\n"
     "The method returns 'nil' if the name is not a valid layer name.\n"
     "See \\register and the make_... methods for a description of layer naming.\n"
+    "\n"
+    "It is in the responsibility of the user to use \\texts_by_index or \\polygons_by_index on the right layers. "
+    "A layer created for text purpose should not be used with \\polygons_by_index or vice versa.\n"
+    "\n"
+    "Starting with version 0.30, the preferred name for this method is \\polygons_by_index to "
+    "differentiate from \\texts_by_index."
   ) +
-  gsi::factory ("layer_by_index", &db::LayoutToNetlist::layer_by_index, gsi::arg ("index"),
-    "@brief Gets a layer object for the given index.\n"
+  gsi::factory ("texts_by_name", &db::LayoutToNetlist::texts_by_name, gsi::arg ("name"),
+    "@brief Gets a layer object for the given name.\n"
+    "The returned object is a new Texts object representing the named layer. It will refer to a layer inside the "
+    "internal layout, or more specifically inside the \\DeepShapeStorage object (see \\dss and \\internal_layout).\n"
+    "The method returns 'nil' if the name is not a valid layer name.\n"
+    "See \\register and the make_... methods for a description of layer naming.\n"
+    "\n"
+    "It is in the responsibility of the user to use \\texts_by_name or \\polygons_by_name on the right layers. "
+    "A layer created for text purpose should not be used with \\polygons_by_name or vice versa.\n"
+    "\n"
+    "This method has been introduced in version 0.30."
+  ) +
+  gsi::factory ("polygons_by_index|#layer_by_index", &db::LayoutToNetlist::layer_by_index, gsi::arg ("index"),
+    "@brief Gets a \\Region object for the given index.\n"
     "The returned object is a new Region object representing the layer with the given index. It will refer to a layer inside the "
     "internal layout, or more specifically inside the \\DeepShapeStorage object (see \\dss and \\internal_layout).\n"
-    "The method returns 'nil' if the index is not a valid layer index."
+    "The method returns 'nil' if the index is not a valid layer index.\n"
+    "\n"
+    "It is in the responsibility of the user to use \\texts_by_index or \\polygons_by_index on the right layers. "
+    "A layer created for text purpose should not be used with \\polygons_by_index or vice versa.\n"
+    "\n"
+    "Starting with version 0.30, the preferred name for this method is \\polygons_by_index to "
+    "differentiate from \\texts_by_index."
+  ) +
+  gsi::factory ("texts_by_index", &db::LayoutToNetlist::texts_by_index, gsi::arg ("index"),
+    "@brief Gets a \\Texts object for the given index.\n"
+    "The returned object is a new Texts object representing the layer with the given index. It will refer to a layer inside the "
+    "internal layout, or more specifically inside the \\DeepShapeStorage object (see \\dss and \\internal_layout).\n"
+    "The method returns 'nil' if the index is not a valid layer index.\n"
+    "\n"
+    "It is in the responsibility of the user to use \\texts_by_index or \\polygons_by_index on the right layers. "
+    "A layer created for text purpose should not be used with \\polygons_by_index or vice versa.\n"
+    "\n"
+    "This method has been introduced in version 0.30."
   ) +
   gsi::method ("is_persisted?", &db::LayoutToNetlist::is_persisted<db::Region>, gsi::arg ("layer"),
     "@brief Returns true, if the given layer is a persisted region.\n"
@@ -446,14 +542,14 @@ Class<db::LayoutToNetlist> decl_dbLayoutToNetlist ("db", "LayoutToNetlist",
     "\n"
     "The variant for Texts collections has been added in version 0.27."
   ) +
-  gsi::factory ("make_layer", (db::Region *(db::LayoutToNetlist::*) (const std::string &)) &db::LayoutToNetlist::make_layer, gsi::arg ("name", std::string ()),
+  gsi::factory ("make_layer", (db::Region *(db::LayoutToNetlist::*) (const std::string &)) &db::LayoutToNetlist::make_layer, gsi::arg ("name", std::string (), "\"\""),
     "@brief Creates a new, empty hierarchical region\n"
     "\n"
     "This method will create a new, empty layer inside the internal layout and register it.\n"
     "It returns a new Region object that represents the new layer. See the class description for more details.\n"
     "The name is optional. If given, the layer will already be named accordingly (see \\register).\n"
   ) +
-  gsi::factory ("make_layer", (db::Region *(db::LayoutToNetlist::*) (unsigned int, const std::string &)) &db::LayoutToNetlist::make_layer, gsi::arg ("layer_index"), gsi::arg ("name", std::string ()),
+  gsi::factory ("make_layer", (db::Region *(db::LayoutToNetlist::*) (unsigned int, const std::string &)) &db::LayoutToNetlist::make_layer, gsi::arg ("layer_index"), gsi::arg ("name", std::string (), "\"\""),
     "@brief Creates a new hierarchical region representing an original layer\n"
     "'layer_index' is the layer index of the desired layer in the original layout.\n"
     "This variant produces polygons and takes texts for net name annotation as special, property-annotated polygons.\n"
@@ -464,13 +560,25 @@ Class<db::LayoutToNetlist> decl_dbLayoutToNetlist ("db", "LayoutToNetlist",
     "the DSS (see \\dss and \\internal_layout). It returns a new Region object that represents this layer copy. "
     "The new layer is already registered with the given name and can be used for \\connect for example.\n"
   ) +
-  gsi::factory ("make_text_layer", &db::LayoutToNetlist::make_text_layer, gsi::arg ("layer_index"), gsi::arg ("name", std::string ()),
-    "@brief Creates a new region representing an original layer taking texts only\n"
+  gsi::factory ("make_text_layer", (db::Texts *(db::LayoutToNetlist::*) (const std::string &)) &db::LayoutToNetlist::make_text_layer, gsi::arg ("name", std::string (), "\"\""),
+    "@brief Creates a new, empty hierarchical text collection\n"
+    "See \\make_layer for details.\n"
+    "\n"
+    "Starting with version 0.30, the original layer index is optional, allowing to create empty, internal text layers."
+  ) +
+  gsi::factory ("make_text_layer", (db::Texts *(db::LayoutToNetlist::*) (unsigned int, const std::string &)) &db::LayoutToNetlist::make_text_layer, gsi::arg ("layer_index"), gsi::arg ("name", std::string (), "\"\""),
+    "@brief Creates a new text collection representing an original layer taking texts only\n"
     "See \\make_layer for details.\n"
     "\n"
     "Starting with version 0.27, this method returns a \\Texts object."
   ) +
-  gsi::factory ("make_polygon_layer", &db::LayoutToNetlist::make_polygon_layer, gsi::arg ("layer_index"), gsi::arg ("name", std::string ()),
+  gsi::factory ("make_polygon_layer", (db::Region *(db::LayoutToNetlist::*) (const std::string &)) &db::LayoutToNetlist::make_layer, gsi::arg ("name", std::string (), "\"\""),
+    "@brief Creates a new, empty hierarchical region\n"
+    "See \\make_layer for details.\n"
+    "\n"
+    "Starting with version 0.30, the original layer index is optional for consistency with \\make_layer."
+  ) +
+  gsi::factory ("make_polygon_layer", (db::Region *(db::LayoutToNetlist::*) (unsigned int, const std::string &)) &db::LayoutToNetlist::make_polygon_layer, gsi::arg ("layer_index"), gsi::arg ("name", std::string (), "\"\""),
     "@brief Creates a new region representing an original layer taking polygons only\n"
     "See \\make_layer for details.\n"
   ) +
@@ -661,7 +769,7 @@ Class<db::LayoutToNetlist> decl_dbLayoutToNetlist ("db", "LayoutToNetlist",
     "@ul\n"
     "@li \"\" no implicit connections.@/li\n"
     "@li \"*\" to make all labels candidates for implicit connections.@/li\n"
-    "@li \"VDD\" to make all 'VDD'' nets candidates for implicit connections.@/li\n"
+    "@li \"VDD\" to make all 'VDD' nets candidates for implicit connections.@/li\n"
     "@li \"VDD\" to make all 'VDD'+suffix nets candidates for implicit connections.@/li\n"
     "@li \"{VDD,VSS}\" to all VDD and VSS nets candidates for implicit connections.@/li\n"
     "@/ul\n"
@@ -713,6 +821,16 @@ Class<db::LayoutToNetlist> decl_dbLayoutToNetlist ("db", "LayoutToNetlist",
     "\n"
     "This method has been introduced in version 0.28.13."
   ) +
+  gsi::method_ext ("original_layout", &l2n_original_layout,
+    "@brief Gets the original layout or nil is the LayoutToNetlist object is not attached to one.\n"
+    "\n"
+    "This method has been introduced in version 0.30."
+  ) +
+  gsi::method_ext ("original_top_cell", &l2n_original_top_cell,
+    "@brief Gets the original top cell or nil is the LayoutToNetlist object is not attached to an original layout.\n"
+    "\n"
+    "This method has been introduced in version 0.30."
+  ) +
   gsi::method_ext ("internal_layout", &l2n_internal_layout,
     "@brief Gets the internal layout\n"
     "The internal layout is where the LayoutToNetlist database stores the shapes for the nets. "
@@ -729,17 +847,20 @@ Class<db::LayoutToNetlist> decl_dbLayoutToNetlist ("db", "LayoutToNetlist",
     "\n"
     "See the class description for details about the internal layout object."
   ) +
-  gsi::method ("layer_of", &db::LayoutToNetlist::layer_of<db::Region>, gsi::arg ("l"),
+  gsi::method ("#layer_of", &db::LayoutToNetlist::layer_of<db::Region>, gsi::arg ("l"),
     "@brief Gets the internal layer for a given extraction layer\n"
     "This method is required to derive the internal layer index - for example for\n"
     "investigating the cluster tree.\n"
+    "\n"
+    "A generalized version of this method is \\layer_index."
   ) +
-  gsi::method ("layer_of", &db::LayoutToNetlist::layer_of<db::Texts>, gsi::arg ("l"),
+  gsi::method ("#layer_of", &db::LayoutToNetlist::layer_of<db::Texts>, gsi::arg ("l"),
     "@brief Gets the internal layer for a given text collection\n"
     "This method is required to derive the internal layer index - for example for\n"
     "investigating the cluster tree.\n"
     "\n"
     "The variant for Texts collections has been added in version 0.27.\n"
+    "A generalized version of this method is \\layer_index."
   ) +
   gsi::method ("cell_mapping_into", (db::CellMapping (db::LayoutToNetlist::*) (db::Layout &, db::Cell &, bool)) &db::LayoutToNetlist::cell_mapping_into, gsi::arg ("layout"), gsi::arg ("cell"), gsi::arg ("with_device_cells", false),
     "@brief Creates a cell mapping for copying shapes from the internal layout to the given target layout.\n"
@@ -760,7 +881,7 @@ Class<db::LayoutToNetlist> decl_dbLayoutToNetlist ("db", "LayoutToNetlist",
   gsi::method ("const_cell_mapping_into", &db::LayoutToNetlist::const_cell_mapping_into, gsi::arg ("layout"), gsi::arg ("cell"),
     "@brief Creates a cell mapping for copying shapes from the internal layout to the given target layout.\n"
     "This version will not create new cells in the target layout.\n"
-    "If the required cells do not exist there yet, flatting will happen.\n"
+    "If some required cells do not exist there, they will be flattened into the first existing parent.\n"
   ) +
   gsi::method ("netlist", &db::LayoutToNetlist::netlist,
     "@brief gets the netlist extracted (0 if no extraction happened yet)\n"
@@ -804,19 +925,60 @@ Class<db::LayoutToNetlist> decl_dbLayoutToNetlist ("db", "LayoutToNetlist",
     "This method has been introduced in version 0.29.2."
   ) +
   gsi::factory ("shapes_of_net", (db::Region *(db::LayoutToNetlist::*) (const db::Net &, const db::Region &, bool, const db::ICplxTrans &) const) &db::LayoutToNetlist::shapes_of_net, gsi::arg ("net"), gsi::arg ("of_layer"), gsi::arg ("recursive", true), gsi::arg ("trans", db::ICplxTrans (), "unity"),
-    "@brief Returns all shapes of a specific net and layer.\n"
-    "If 'recursive'' is true, the returned region will contain the shapes of\n"
+    "@brief Returns all polygons of a specific net and layer.\n"
+    "If 'recursive' is true, the returned region will contain the shapes of\n"
     "all subcircuits too.\n"
     "\n"
     "The optional 'trans' parameter allows applying a transformation to all shapes. It has been introduced in version 0.28.4."
   ) +
-  gsi::method ("shapes_of_net", (void (db::LayoutToNetlist::*) (const db::Net &, const db::Region &, bool, db::Shapes &, db::properties_id_type, const db::ICplxTrans &) const) &db::LayoutToNetlist::shapes_of_net, gsi::arg ("net"), gsi::arg ("of_layer"), gsi::arg ("recursive"), gsi::arg ("to"), gsi::arg ("propid", db::properties_id_type (0), "0"), gsi::arg ("trans", db::ICplxTrans (), "unity"),
-    "@brief Sends all shapes of a specific net and layer to the given Shapes container.\n"
-    "If 'recursive'' is true, the returned region will contain the shapes of\n"
+  gsi::factory ("shapes_of_net", (db::Texts *(db::LayoutToNetlist::*) (const db::Net &, const db::Texts &, bool, const db::ICplxTrans &) const) &db::LayoutToNetlist::shapes_of_net, gsi::arg ("net"), gsi::arg ("of_layer"), gsi::arg ("recursive", true), gsi::arg ("trans", db::ICplxTrans (), "unity"),
+    "@brief Returns all texts of a specific net and layer.\n"
+    "If 'recursive' is true, the returned text collection will contain the shapes of\n"
     "all subcircuits too.\n"
-    "\"prop_id\" is an optional properties ID. If given, this property set will be attached to the shapes."
+    "\n"
+    "The optional 'trans' parameter allows applying a transformation to all shapes.\n"
+    "\n"
+    "This variant has been introduced in version 0.30."
+  ) +
+  gsi::factory ("polygons_of_net", (db::Region *(db::LayoutToNetlist::*) (const db::Net &, unsigned int, bool, const db::ICplxTrans &) const) &db::LayoutToNetlist::shapes_of_net_with_layer_index<db::Region>, gsi::arg ("net"), gsi::arg ("of_layer"), gsi::arg ("recursive", true), gsi::arg ("trans", db::ICplxTrans (), "unity"),
+    "@brief Returns all polygons of a specific net and layer.\n"
+    "If 'recursive' is true, the returned region will contain the shapes of\n"
+    "all subcircuits too.\n"
+    "\n"
+    "The optional 'trans' parameter allows applying a transformation to all shapes.\n"
+    "\n"
+    "This method is similar to \\shapes_of_net, but takes a layer index for the layer. It was introduced in version 0.30.\n"
+  ) +
+  gsi::factory ("texts_of_net", (db::Texts *(db::LayoutToNetlist::*) (const db::Net &, unsigned int, bool, const db::ICplxTrans &) const) &db::LayoutToNetlist::shapes_of_net_with_layer_index<db::Texts>, gsi::arg ("net"), gsi::arg ("of_layer"), gsi::arg ("recursive", true), gsi::arg ("trans", db::ICplxTrans (), "unity"),
+    "@brief Returns all texts of a specific net and layer.\n"
+    "If 'recursive' is true, the returned region will contain the shapes of\n"
+    "all subcircuits too.\n"
+    "\n"
+    "The optional 'trans' parameter allows applying a transformation to all shapes.\n"
+    "\n"
+    "This method is similar to \\shapes_of_net, but takes a layer index for the layer. It was introduced in version 0.30.\n"
+  ) +
+  gsi::method ("shapes_of_net", (void (db::LayoutToNetlist::*) (const db::Net &, const db::ShapeCollection &, bool, db::Shapes &, db::properties_id_type, const db::ICplxTrans &) const) &db::LayoutToNetlist::shapes_of_net, gsi::arg ("net"), gsi::arg ("of_layer"), gsi::arg ("recursive"), gsi::arg ("to"), gsi::arg ("propid", db::properties_id_type (0), "0"), gsi::arg ("trans", db::ICplxTrans (), "unity"),
+    "@brief Sends all shapes of a specific net and layer to the given Shapes container.\n"
+    "If 'recursive' is true, the returned region will contain the shapes of\n"
+    "all subcircuits too.\n"
+    "\n"
+    "'prop_id' is an optional properties ID. If given, this property set will be attached to the shapes."
     "\n"
     "The optional 'trans' parameter allows applying a transformation to all shapes. It has been introduced in version 0.28.4."
+    "\n"
+    "The 'of_layer' argument has been generalized in version 0.30 and can be a layer index, a \\Region layer or a \\Texts layer."
+  ) +
+  gsi::method ("shapes_of_net", (void (db::LayoutToNetlist::*) (const db::Net &, unsigned int, bool, db::Shapes &, db::properties_id_type, const db::ICplxTrans &) const) &db::LayoutToNetlist::shapes_of_net, gsi::arg ("net"), gsi::arg ("of_layer"), gsi::arg ("recursive"), gsi::arg ("to"), gsi::arg ("propid", db::properties_id_type (0), "0"), gsi::arg ("trans", db::ICplxTrans (), "unity"),
+    "@brief Sends all shapes of a specific net and layer to the given Shapes container.\n"
+    "If 'recursive' is true, the returned region will contain the shapes of\n"
+    "all subcircuits too.\n"
+    "\n"
+    "'prop_id' is an optional properties ID. If given, this property set will be attached to the shapes."
+    "\n"
+    "The optional 'trans' parameter allows applying a transformation to all shapes. It has been introduced in version 0.28.4."
+    "\n"
+    "The 'of_layer' argument has been generalized in version 0.30 and can be a layer index, a \\Region layer or a \\Texts layer."
   ) +
   gsi::method_ext ("build_net", &build_net, gsi::arg ("net"), gsi::arg ("target"), gsi::arg ("target_cell"), gsi::arg ("lmap"), gsi::arg ("netname_prop", tl::Variant (), "nil"), gsi::arg ("hier_mode", db::BNH_Flatten, "BNH_Flatten"), gsi::arg ("circuit_cell_name_prefix", tl::Variant (), "nil"), gsi::arg ("device_cell_name_prefix", tl::Variant (), "nil"),
     "@brief Builds a net representation in the given layout and cell\n"
@@ -828,9 +990,9 @@ Class<db::LayoutToNetlist> decl_dbLayoutToNetlist ("db", "LayoutToNetlist",
     "of the property is the net name.\n"
     "\n"
     "'lmap' defines which layers are to be produced. It is map, where the keys are layer indexes in the "
-    "target layout and the values are Region objects indicating the layer where shapes are to be taken from. "
-    "Use \\layer_by_name or \\layer_by_index to get the Region object corresponding to a layer stored inside "
-    "the LayoutToNetlist database. See \\build_all_nets for a code sample.\n"
+    "target layout and the values are Region or Texts objects or layer indexes, indicating the layer where shapes are to be taken from. "
+    "'lmap' can also be left nil, in which case, a layer mapping will be provided based on the layer info attributes of "
+    "the layers (see \\layer_info).\n"
     "\n"
     "Also see \\build_all_nets for a description of the 'hier_mode' argument.\n"
     "\n"
@@ -840,13 +1002,15 @@ Class<db::LayoutToNetlist> decl_dbLayoutToNetlist ("db", "LayoutToNetlist",
     "\n"
     "@param target The target layout\n"
     "@param target_cell The target cell\n"
-    "@param lmap Target layer indexes (keys) and net regions (values)\n"
+    "@param lmap The layer mapping (see description of this method)\n"
     "@param hier_mode See description of this method\n"
     "@param netname_prop An (optional) property name to which to attach the net name\n"
     "@param cell_name_prefix Chooses recursive mode if non-null\n"
     "@param device_cell_name_prefix See above\n"
+    "\n"
+    "The 'lmap' argument has been generalized in version 0.30 and became optional."
   ) +
-  gsi::method_ext ("build_all_nets", &build_all_nets, gsi::arg ("cmap"), gsi::arg ("target"), gsi::arg ("lmap"), gsi::arg ("net_cell_name_prefix", tl::Variant (), "nil"), gsi::arg ("netname_prop", tl::Variant (), "nil"), gsi::arg ("hier_mode", db::BNH_Flatten, "BNH_Flatten"), gsi::arg ("circuit_cell_name_prefix", tl::Variant (), "nil"), gsi::arg ("device_cell_name_prefix", tl::Variant (), "nil"),
+  gsi::method_ext ("build_all_nets", &build_all_nets, gsi::arg ("cmap"), gsi::arg ("target"), gsi::arg ("lmap", tl::Variant (), "auto"), gsi::arg ("net_cell_name_prefix", tl::Variant (), "nil"), gsi::arg ("netname_prop", tl::Variant (), "nil"), gsi::arg ("hier_mode", db::BNH_Flatten, "BNH_Flatten"), gsi::arg ("circuit_cell_name_prefix", tl::Variant (), "nil"), gsi::arg ("device_cell_name_prefix", tl::Variant (), "nil"),
     "@brief Builds a full hierarchical representation of the nets\n"
     "\n"
     "This method copies all nets into cells corresponding to the circuits. It uses the 'cmap'\n"
@@ -858,22 +1022,12 @@ Class<db::LayoutToNetlist> decl_dbLayoutToNetlist ("db", "LayoutToNetlist",
     "of the property is the net name.\n"
     "\n"
     "'lmap' defines which layers are to be produced. It is map, where the keys are layer indexes in the "
-    "target layout and the values are Region objects indicating the layer where shapes are to be taken from. "
-    "Use \\layer_by_name or \\layer_by_index to get the Region object corresponding to a layer stored inside "
-    "the LayoutToNetlist database.\n"
+    "target layout and the values are Region or Texts objects or layer indexes, indicating the layer where shapes are to be taken from. "
+    "'lmap' can also be left nil, in which case, a layer mapping will be provided based on the layer info attributes of "
+    "the layers (see \\layer_info).\n"
     "\n"
-    "You can use the following code to replicate the layers inside the LayoutToNetlist object into a fresh target layout "
-    "and create the layer map for the 'lmap' argument:\n"
-    "\n"
-    "@code\n"
-    "l2n = ... some LayoutToNetlist object\n"
-    "target = ... some fresh target layout\n"
-    "lmap = {}\n"
-    "l2n.layer_indexes().each do |layer_index|\n"
-    "  new_layer_index = target.layer(l2n.layer_info(li))\n"
-    "  lmap[new_layer_index] = l2n.layer_by_index(li)\n"
-    "end\n"
-    "@/code\n"
+    "'cmap' specifies the cell mapping. Use \\create_cell_mapping or \\const_create_cell_mapping to "
+    "define the target cells in the target layout and to derive a cell mapping.\n"
     "\n"
     "The method has three net annotation modes:\n"
     "@ul\n"
@@ -900,14 +1054,16 @@ Class<db::LayoutToNetlist> decl_dbLayoutToNetlist ("db", "LayoutToNetlist",
     "using a name like device_cell_name_prefix + device name. Otherwise the device shapes are\n"
     "treated as part of the net.\n"
     "\n"
-    "@param cmap The mapping of internal layout to target layout for the circuit mapping\n"
+    "@param cmap The cell mapping (see description of this method)\n"
     "@param target The target layout\n"
-    "@param lmap Target layer indexes (keys) and net regions (values)\n"
+    "@param lmap The layer mapping (see description of this method)\n"
     "@param hier_mode See description of this method\n"
     "@param netname_prop An (optional) property name to which to attach the net name\n"
     "@param circuit_cell_name_prefix See method description\n"
     "@param net_cell_name_prefix See method description\n"
     "@param device_cell_name_prefix See above\n"
+    "\n"
+    "The 'lmap' argument has been generalized in version 0.30 and became optional."
   ) +
   gsi::method_ext ("build_nets", &build_nets, gsi::arg ("nets"), gsi::arg ("cmap"), gsi::arg ("target"), gsi::arg ("lmap"), gsi::arg ("net_cell_name_prefix", tl::Variant (), "nil"), gsi::arg ("netname_prop", tl::Variant (), "nil"), gsi::arg ("hier_mode", db::BNH_Flatten, "BNH_Flatten"), gsi::arg ("circuit_cell_name_prefix", tl::Variant (), "nil"), gsi::arg ("device_cell_name_prefix", tl::Variant (), "nil"),
     "@brief Like \\build_all_nets, but with the ability to select some nets."
@@ -1074,7 +1230,7 @@ Class<db::LayoutToNetlist> decl_dbLayoutToNetlist ("db", "LayoutToNetlist",
   "a new LayoutToNetlist object, there will be no connection to any external layout, but all the "
   "essential netlist and geometry information will be available.\n"
   "\n"
-  "The LayoutToNetlist object is also the entry point for netlist-driven algorithms such as antenna checks.\n"
+  "The \\LayoutToNetlist object is also the entry point for netlist-driven algorithms such as antenna checks.\n"
   "\n"
   "The use model of the LayoutToNetlist object consists of five steps which need to be executed in this order.\n"
   "\n"
@@ -1136,8 +1292,26 @@ Class<db::LayoutToNetlist> decl_dbLayoutToNetlist ("db", "LayoutToNetlist",
   "@li Helper functions: \\cell_mapping_into, \\const_cell_mapping_into @/li\n"
   "@/ul\n"
   "\n"
-  "The \\LayoutToNetlist object is also the entry point for connectivity-aware DRC checks, "
-  "such as antenna checks.\n"
+  "Layers stored inside the LayoutToNetlist object are addressed in three ways:\n"
+  "\n"
+  "@ul\n"
+  "@li Through a layer index: this is an integer number that addresses the layer. Technically this is "
+  "    the layer index inside the internal layout (see \\internal_layout). To get a layer index from "
+  "    a shape collection or name use \\layer_index. To get all layer indexes available, use \\layer_indexes. "
+  "    Note, that \\make_layer, \\make_polygon_layer and \\make_text_layer also take a layer index, but "
+  "    this the layer index of layer in the \\original_layout. @/li\n"
+  "@li Through a name: Alternatively to the layer index, a layer can be addressed by name, provided one was "
+  "    assigned. To assign a name, specify one when creating a layer with \\register, \\make_layer, \\make_polygon_layer "
+  "    or \\make_text_layer. To get the layer index of a named layer, use \\layer_index. To get the name "
+  "    of a layer use \\layer_name. To get all names of layers, use \\layer_names. @/li\n"
+  "@li As a shape collection: a layer can also be represented by a shape collection. A shape collection is "
+  "    either a \\Region or a \\Texts object. These objects do not only represent a layer, but can be used "
+  "    to derive new layers. In order to assign names, use \\register. To create a new layer and a "
+  "    corresponding shape collection object, use \\make_layer, \\make_polygon_layer or \\make_text_layer. "
+  "    The get the shape collection for a given layer index, use \\layer_index, to get layer name from "
+  "    a shape collection, use \\layer_name. To get a shape collection from a layer index, use "
+  "    \\layer_by_index, \\polygons_by_index or \\texts_by_index. @li\n"
+  "@/ul\n"
   "\n"
   "This class has been introduced in version 0.26."
 );
diff --git a/src/db/unit_tests/dbLayoutToNetlistReaderTests.cc b/src/db/unit_tests/dbLayoutToNetlistReaderTests.cc
index 251fbe70b..91531d4de 100644
--- a/src/db/unit_tests/dbLayoutToNetlistReaderTests.cc
+++ b/src/db/unit_tests/dbLayoutToNetlistReaderTests.cc
@@ -64,15 +64,15 @@ TEST(1_ReaderBasic)
 
     db::CellMapping cm = l2n.cell_mapping_into (ly2, top2, true /*with device cells*/);
 
-    std::map<unsigned int, const db::Region *> lmap;
-    lmap [ly2.insert_layer (db::LayerProperties (10, 0))] = l2n.layer_by_name ("psd");
-    lmap [ly2.insert_layer (db::LayerProperties (11, 0))] = l2n.layer_by_name ("nsd");
-    lmap [ly2.insert_layer (db::LayerProperties (3, 0)) ] = l2n.layer_by_name ("poly");
-    lmap [ly2.insert_layer (db::LayerProperties (4, 0)) ] = l2n.layer_by_name ("diff_cont");
-    lmap [ly2.insert_layer (db::LayerProperties (5, 0)) ] = l2n.layer_by_name ("poly_cont");
-    lmap [ly2.insert_layer (db::LayerProperties (6, 0)) ] = l2n.layer_by_name ("metal1");
-    lmap [ly2.insert_layer (db::LayerProperties (7, 0)) ] = l2n.layer_by_name ("via1");
-    lmap [ly2.insert_layer (db::LayerProperties (8, 0)) ] = l2n.layer_by_name ("metal2");
+    std::map<unsigned int, unsigned int> lmap;
+    lmap [ly2.insert_layer (db::LayerProperties (10, 0))] = l2n.layer_index_by_name ("psd").value ();
+    lmap [ly2.insert_layer (db::LayerProperties (11, 0))] = l2n.layer_index_by_name ("nsd").value ();
+    lmap [ly2.insert_layer (db::LayerProperties (3, 0)) ] = l2n.layer_index_by_name ("poly").value ();
+    lmap [ly2.insert_layer (db::LayerProperties (4, 0)) ] = l2n.layer_index_by_name ("diff_cont").value ();
+    lmap [ly2.insert_layer (db::LayerProperties (5, 0)) ] = l2n.layer_index_by_name ("poly_cont").value ();
+    lmap [ly2.insert_layer (db::LayerProperties (6, 0)) ] = l2n.layer_index_by_name ("metal1").value ();
+    lmap [ly2.insert_layer (db::LayerProperties (7, 0)) ] = l2n.layer_index_by_name ("via1").value ();
+    lmap [ly2.insert_layer (db::LayerProperties (8, 0)) ] = l2n.layer_index_by_name ("metal2").value ();
 
     l2n.build_all_nets (cm, ly2, lmap, "NET_", db::NPM_NoProperties, tl::Variant (), db::BNH_Disconnected, 0, "DEVICE_");
 
@@ -88,15 +88,15 @@ TEST(1_ReaderBasic)
     ly2.dbu (l2n.internal_layout ()->dbu ());
     db::Cell &top2 = ly2.cell (ly2.add_cell ("TOP"));
 
-    std::map<unsigned int, const db::Region *> lmap;
-    lmap [ly2.insert_layer (db::LayerProperties (10, 0))] = l2n.layer_by_name ("psd");
-    lmap [ly2.insert_layer (db::LayerProperties (11, 0))] = l2n.layer_by_name ("nsd");
-    lmap [ly2.insert_layer (db::LayerProperties (3, 0)) ] = l2n.layer_by_name ("poly");
-    lmap [ly2.insert_layer (db::LayerProperties (4, 0)) ] = l2n.layer_by_name ("diff_cont");
-    lmap [ly2.insert_layer (db::LayerProperties (5, 0)) ] = l2n.layer_by_name ("poly_cont");
-    lmap [ly2.insert_layer (db::LayerProperties (6, 0)) ] = l2n.layer_by_name ("metal1");
-    lmap [ly2.insert_layer (db::LayerProperties (7, 0)) ] = l2n.layer_by_name ("via1");
-    lmap [ly2.insert_layer (db::LayerProperties (8, 0)) ] = l2n.layer_by_name ("metal2");
+    std::map<unsigned int, unsigned int> lmap;
+    lmap [ly2.insert_layer (db::LayerProperties (10, 0))] = l2n.layer_index_by_name ("psd").value ();
+    lmap [ly2.insert_layer (db::LayerProperties (11, 0))] = l2n.layer_index_by_name ("nsd").value ();
+    lmap [ly2.insert_layer (db::LayerProperties (3, 0)) ] = l2n.layer_index_by_name ("poly").value ();
+    lmap [ly2.insert_layer (db::LayerProperties (4, 0)) ] = l2n.layer_index_by_name ("diff_cont").value ();
+    lmap [ly2.insert_layer (db::LayerProperties (5, 0)) ] = l2n.layer_index_by_name ("poly_cont").value ();
+    lmap [ly2.insert_layer (db::LayerProperties (6, 0)) ] = l2n.layer_index_by_name ("metal1").value ();
+    lmap [ly2.insert_layer (db::LayerProperties (7, 0)) ] = l2n.layer_index_by_name ("via1").value ();
+    lmap [ly2.insert_layer (db::LayerProperties (8, 0)) ] = l2n.layer_index_by_name ("metal2").value ();
 
     std::vector<const db::Net *> nets;
     nets.push_back (l2n.netlist ()->circuit_by_name ("RINGO")->net_by_name ("VSS"));
@@ -118,15 +118,15 @@ TEST(1_ReaderBasic)
     ly2.dbu (l2n.internal_layout ()->dbu ());
     db::Cell &top2 = ly2.cell (ly2.add_cell ("TOP"));
 
-    std::map<unsigned int, const db::Region *> lmap;
-    lmap [ly2.insert_layer (db::LayerProperties (10, 0))] = l2n.layer_by_name ("psd");
-    lmap [ly2.insert_layer (db::LayerProperties (11, 0))] = l2n.layer_by_name ("nsd");
-    lmap [ly2.insert_layer (db::LayerProperties (3, 0)) ] = l2n.layer_by_name ("poly");
-    lmap [ly2.insert_layer (db::LayerProperties (4, 0)) ] = l2n.layer_by_name ("diff_cont");
-    lmap [ly2.insert_layer (db::LayerProperties (5, 0)) ] = l2n.layer_by_name ("poly_cont");
-    lmap [ly2.insert_layer (db::LayerProperties (6, 0)) ] = l2n.layer_by_name ("metal1");
-    lmap [ly2.insert_layer (db::LayerProperties (7, 0)) ] = l2n.layer_by_name ("via1");
-    lmap [ly2.insert_layer (db::LayerProperties (8, 0)) ] = l2n.layer_by_name ("metal2");
+    std::map<unsigned int, unsigned int> lmap;
+    lmap [ly2.insert_layer (db::LayerProperties (10, 0))] = l2n.layer_index_by_name ("psd").value ();
+    lmap [ly2.insert_layer (db::LayerProperties (11, 0))] = l2n.layer_index_by_name ("nsd").value ();
+    lmap [ly2.insert_layer (db::LayerProperties (3, 0)) ] = l2n.layer_index_by_name ("poly").value ();
+    lmap [ly2.insert_layer (db::LayerProperties (4, 0)) ] = l2n.layer_index_by_name ("diff_cont").value ();
+    lmap [ly2.insert_layer (db::LayerProperties (5, 0)) ] = l2n.layer_index_by_name ("poly_cont").value ();
+    lmap [ly2.insert_layer (db::LayerProperties (6, 0)) ] = l2n.layer_index_by_name ("metal1").value ();
+    lmap [ly2.insert_layer (db::LayerProperties (7, 0)) ] = l2n.layer_index_by_name ("via1").value ();
+    lmap [ly2.insert_layer (db::LayerProperties (8, 0)) ] = l2n.layer_index_by_name ("metal2").value ();
 
     std::vector<const db::Net *> nets;
     nets.push_back (l2n.netlist ()->circuit_by_name ("RINGO")->net_by_name ("VSS"));
@@ -148,15 +148,15 @@ TEST(1_ReaderBasic)
     ly2.dbu (l2n.internal_layout ()->dbu ());
     db::Cell &top2 = ly2.cell (ly2.add_cell ("TOP"));
 
-    std::map<unsigned int, const db::Region *> lmap;
-    lmap [ly2.insert_layer (db::LayerProperties (10, 0))] = l2n.layer_by_name ("psd");
-    lmap [ly2.insert_layer (db::LayerProperties (11, 0))] = l2n.layer_by_name ("nsd");
-    lmap [ly2.insert_layer (db::LayerProperties (3, 0)) ] = l2n.layer_by_name ("poly");
-    lmap [ly2.insert_layer (db::LayerProperties (4, 0)) ] = l2n.layer_by_name ("diff_cont");
-    lmap [ly2.insert_layer (db::LayerProperties (5, 0)) ] = l2n.layer_by_name ("poly_cont");
-    lmap [ly2.insert_layer (db::LayerProperties (6, 0)) ] = l2n.layer_by_name ("metal1");
-    lmap [ly2.insert_layer (db::LayerProperties (7, 0)) ] = l2n.layer_by_name ("via1");
-    lmap [ly2.insert_layer (db::LayerProperties (8, 0)) ] = l2n.layer_by_name ("metal2");
+    std::map<unsigned int, unsigned int> lmap;
+    lmap [ly2.insert_layer (db::LayerProperties (10, 0))] = l2n.layer_index_by_name ("psd").value ();
+    lmap [ly2.insert_layer (db::LayerProperties (11, 0))] = l2n.layer_index_by_name ("nsd").value ();
+    lmap [ly2.insert_layer (db::LayerProperties (3, 0)) ] = l2n.layer_index_by_name ("poly").value ();
+    lmap [ly2.insert_layer (db::LayerProperties (4, 0)) ] = l2n.layer_index_by_name ("diff_cont").value ();
+    lmap [ly2.insert_layer (db::LayerProperties (5, 0)) ] = l2n.layer_index_by_name ("poly_cont").value ();
+    lmap [ly2.insert_layer (db::LayerProperties (6, 0)) ] = l2n.layer_index_by_name ("metal1").value ();
+    lmap [ly2.insert_layer (db::LayerProperties (7, 0)) ] = l2n.layer_index_by_name ("via1").value ();
+    lmap [ly2.insert_layer (db::LayerProperties (8, 0)) ] = l2n.layer_index_by_name ("metal2").value ();
 
     std::vector<const db::Net *> nets;
     nets.push_back (l2n.netlist ()->circuit_by_name ("RINGO")->net_by_name ("VSS"));
@@ -178,15 +178,15 @@ TEST(1_ReaderBasic)
     ly2.dbu (l2n.internal_layout ()->dbu ());
     db::Cell &top2 = ly2.cell (ly2.add_cell ("TOP"));
 
-    std::map<unsigned int, const db::Region *> lmap;
-    lmap [ly2.insert_layer (db::LayerProperties (10, 0))] = l2n.layer_by_name ("psd");
-    lmap [ly2.insert_layer (db::LayerProperties (11, 0))] = l2n.layer_by_name ("nsd");
-    lmap [ly2.insert_layer (db::LayerProperties (3, 0)) ] = l2n.layer_by_name ("poly");
-    lmap [ly2.insert_layer (db::LayerProperties (4, 0)) ] = l2n.layer_by_name ("diff_cont");
-    lmap [ly2.insert_layer (db::LayerProperties (5, 0)) ] = l2n.layer_by_name ("poly_cont");
-    lmap [ly2.insert_layer (db::LayerProperties (6, 0)) ] = l2n.layer_by_name ("metal1");
-    lmap [ly2.insert_layer (db::LayerProperties (7, 0)) ] = l2n.layer_by_name ("via1");
-    lmap [ly2.insert_layer (db::LayerProperties (8, 0)) ] = l2n.layer_by_name ("metal2");
+    std::map<unsigned int, unsigned int> lmap;
+    lmap [ly2.insert_layer (db::LayerProperties (10, 0))] = l2n.layer_index_by_name ("psd").value ();
+    lmap [ly2.insert_layer (db::LayerProperties (11, 0))] = l2n.layer_index_by_name ("nsd").value ();
+    lmap [ly2.insert_layer (db::LayerProperties (3, 0)) ] = l2n.layer_index_by_name ("poly").value ();
+    lmap [ly2.insert_layer (db::LayerProperties (4, 0)) ] = l2n.layer_index_by_name ("diff_cont").value ();
+    lmap [ly2.insert_layer (db::LayerProperties (5, 0)) ] = l2n.layer_index_by_name ("poly_cont").value ();
+    lmap [ly2.insert_layer (db::LayerProperties (6, 0)) ] = l2n.layer_index_by_name ("metal1").value ();
+    lmap [ly2.insert_layer (db::LayerProperties (7, 0)) ] = l2n.layer_index_by_name ("via1").value ();
+    lmap [ly2.insert_layer (db::LayerProperties (8, 0)) ] = l2n.layer_index_by_name ("metal2").value ();
 
     std::vector<const db::Net *> nets;
     nets.push_back (l2n.netlist ()->circuit_by_name ("RINGO")->net_by_name ("VSS"));
@@ -209,15 +209,15 @@ TEST(1_ReaderBasic)
     ly2.dbu (l2n.internal_layout ()->dbu ());
     db::Cell &top2 = ly2.cell (ly2.add_cell ("TOP"));
 
-    std::map<unsigned int, const db::Region *> lmap;
-    lmap [ly2.insert_layer (db::LayerProperties (10, 0))] = l2n.layer_by_name ("psd");
-    lmap [ly2.insert_layer (db::LayerProperties (11, 0))] = l2n.layer_by_name ("nsd");
-    lmap [ly2.insert_layer (db::LayerProperties (3, 0)) ] = l2n.layer_by_name ("poly");
-    lmap [ly2.insert_layer (db::LayerProperties (4, 0)) ] = l2n.layer_by_name ("diff_cont");
-    lmap [ly2.insert_layer (db::LayerProperties (5, 0)) ] = l2n.layer_by_name ("poly_cont");
-    lmap [ly2.insert_layer (db::LayerProperties (6, 0)) ] = l2n.layer_by_name ("metal1");
-    lmap [ly2.insert_layer (db::LayerProperties (7, 0)) ] = l2n.layer_by_name ("via1");
-    lmap [ly2.insert_layer (db::LayerProperties (8, 0)) ] = l2n.layer_by_name ("metal2");
+    std::map<unsigned int, unsigned int> lmap;
+    lmap [ly2.insert_layer (db::LayerProperties (10, 0))] = l2n.layer_index_by_name ("psd").value ();
+    lmap [ly2.insert_layer (db::LayerProperties (11, 0))] = l2n.layer_index_by_name ("nsd").value ();
+    lmap [ly2.insert_layer (db::LayerProperties (3, 0)) ] = l2n.layer_index_by_name ("poly").value ();
+    lmap [ly2.insert_layer (db::LayerProperties (4, 0)) ] = l2n.layer_index_by_name ("diff_cont").value ();
+    lmap [ly2.insert_layer (db::LayerProperties (5, 0)) ] = l2n.layer_index_by_name ("poly_cont").value ();
+    lmap [ly2.insert_layer (db::LayerProperties (6, 0)) ] = l2n.layer_index_by_name ("metal1").value ();
+    lmap [ly2.insert_layer (db::LayerProperties (7, 0)) ] = l2n.layer_index_by_name ("via1").value ();
+    lmap [ly2.insert_layer (db::LayerProperties (8, 0)) ] = l2n.layer_index_by_name ("metal2").value ();
 
     std::vector<const db::Net *> nets;
     nets.push_back (l2n.netlist ()->circuit_by_name ("RINGO")->net_by_name ("VSS"));
@@ -290,18 +290,18 @@ TEST(1c_ReaderBasicShortWithProps)
     ly2.dbu (l2n.internal_layout ()->dbu ());
     db::Cell &top2 = ly2.cell (ly2.add_cell ("TOP"));
 
-    std::map<unsigned int, const db::Region *> lmap;
-    lmap [ly2.insert_layer (db::LayerProperties (3, 0))] = l2n.layer_by_name ("poly");
-    lmap [ly2.insert_layer (db::LayerProperties (3, 1))] = l2n.layer_by_name ("poly_lbl");
-    lmap [ly2.insert_layer (db::LayerProperties (4, 0))] = l2n.layer_by_name ("diff_cont");
-    lmap [ly2.insert_layer (db::LayerProperties (5, 0))] = l2n.layer_by_name ("poly_cont");
-    lmap [ly2.insert_layer (db::LayerProperties (6, 0))] = l2n.layer_by_name ("metal1");
-    lmap [ly2.insert_layer (db::LayerProperties (6, 1))] = l2n.layer_by_name ("metal1_lbl");
-    lmap [ly2.insert_layer (db::LayerProperties (7, 0))] = l2n.layer_by_name ("via1");
-    lmap [ly2.insert_layer (db::LayerProperties (8, 0))] = l2n.layer_by_name ("metal2");
-    lmap [ly2.insert_layer (db::LayerProperties (8, 1))] = l2n.layer_by_name ("metal2_lbl");
-    lmap [ly2.insert_layer (db::LayerProperties (10, 0))] = l2n.layer_by_name ("psd");
-    lmap [ly2.insert_layer (db::LayerProperties (11, 0))] = l2n.layer_by_name ("nsd");
+    std::map<unsigned int, unsigned int> lmap;
+    lmap [ly2.insert_layer (db::LayerProperties (3, 0))] = l2n.layer_index_by_name ("poly").value ();
+    lmap [ly2.insert_layer (db::LayerProperties (3, 1))] = l2n.layer_index_by_name ("poly_lbl").value ();
+    lmap [ly2.insert_layer (db::LayerProperties (4, 0))] = l2n.layer_index_by_name ("diff_cont").value ();
+    lmap [ly2.insert_layer (db::LayerProperties (5, 0))] = l2n.layer_index_by_name ("poly_cont").value ();
+    lmap [ly2.insert_layer (db::LayerProperties (6, 0))] = l2n.layer_index_by_name ("metal1").value ();
+    lmap [ly2.insert_layer (db::LayerProperties (6, 1))] = l2n.layer_index_by_name ("metal1_lbl").value ();
+    lmap [ly2.insert_layer (db::LayerProperties (7, 0))] = l2n.layer_index_by_name ("via1").value ();
+    lmap [ly2.insert_layer (db::LayerProperties (8, 0))] = l2n.layer_index_by_name ("metal2").value ();
+    lmap [ly2.insert_layer (db::LayerProperties (8, 1))] = l2n.layer_index_by_name ("metal2_lbl").value ();
+    lmap [ly2.insert_layer (db::LayerProperties (10, 0))] = l2n.layer_index_by_name ("psd").value ();
+    lmap [ly2.insert_layer (db::LayerProperties (11, 0))] = l2n.layer_index_by_name ("nsd").value ();
 
     db::CellMapping cm = l2n.cell_mapping_into (ly2, top2);
 
@@ -347,19 +347,19 @@ TEST(2_ReaderWithGlobalNets)
 
     db::CellMapping cm = l2n.cell_mapping_into (ly2, top2, true /*with device cells*/);
 
-    std::map<unsigned int, const db::Region *> lmap;
-    lmap [ly2.insert_layer (db::LayerProperties (10, 0))] = l2n.layer_by_name ("psd");
-    lmap [ly2.insert_layer (db::LayerProperties (11, 0))] = l2n.layer_by_name ("nsd");
-    lmap [ly2.insert_layer (db::LayerProperties (12, 0))] = l2n.layer_by_name ("rbulk");
-    lmap [ly2.insert_layer (db::LayerProperties (13, 0))] = l2n.layer_by_name ("ptie");
-    lmap [ly2.insert_layer (db::LayerProperties (14, 0))] = l2n.layer_by_name ("ntie");
-    lmap [ly2.insert_layer (db::LayerProperties (1, 0)) ] = l2n.layer_by_name ("nwell");
-    lmap [ly2.insert_layer (db::LayerProperties (3, 0)) ] = l2n.layer_by_name ("poly");
-    lmap [ly2.insert_layer (db::LayerProperties (4, 0)) ] = l2n.layer_by_name ("diff_cont");
-    lmap [ly2.insert_layer (db::LayerProperties (5, 0)) ] = l2n.layer_by_name ("poly_cont");
-    lmap [ly2.insert_layer (db::LayerProperties (6, 0)) ] = l2n.layer_by_name ("metal1");
-    lmap [ly2.insert_layer (db::LayerProperties (7, 0)) ] = l2n.layer_by_name ("via1");
-    lmap [ly2.insert_layer (db::LayerProperties (8, 0)) ] = l2n.layer_by_name ("metal2");
+    std::map<unsigned int, unsigned int> lmap;
+    lmap [ly2.insert_layer (db::LayerProperties (10, 0))] = l2n.layer_index_by_name ("psd").value ();
+    lmap [ly2.insert_layer (db::LayerProperties (11, 0))] = l2n.layer_index_by_name ("nsd").value ();
+    lmap [ly2.insert_layer (db::LayerProperties (12, 0))] = l2n.layer_index_by_name ("rbulk").value ();
+    lmap [ly2.insert_layer (db::LayerProperties (13, 0))] = l2n.layer_index_by_name ("ptie").value ();
+    lmap [ly2.insert_layer (db::LayerProperties (14, 0))] = l2n.layer_index_by_name ("ntie").value ();
+    lmap [ly2.insert_layer (db::LayerProperties (1, 0)) ] = l2n.layer_index_by_name ("nwell").value ();
+    lmap [ly2.insert_layer (db::LayerProperties (3, 0)) ] = l2n.layer_index_by_name ("poly").value ();
+    lmap [ly2.insert_layer (db::LayerProperties (4, 0)) ] = l2n.layer_index_by_name ("diff_cont").value ();
+    lmap [ly2.insert_layer (db::LayerProperties (5, 0)) ] = l2n.layer_index_by_name ("poly_cont").value ();
+    lmap [ly2.insert_layer (db::LayerProperties (6, 0)) ] = l2n.layer_index_by_name ("metal1").value ();
+    lmap [ly2.insert_layer (db::LayerProperties (7, 0)) ] = l2n.layer_index_by_name ("via1").value ();
+    lmap [ly2.insert_layer (db::LayerProperties (8, 0)) ] = l2n.layer_index_by_name ("metal2").value ();
 
     l2n.build_all_nets (cm, ly2, lmap, "NET_", db::NPM_NoProperties, tl::Variant (), db::BNH_SubcircuitCells, "CIRCUIT_", "DEVICE_");
 
@@ -403,19 +403,19 @@ TEST(3_ReaderAbsoluteCoordinates)
 
     db::CellMapping cm = l2n.cell_mapping_into (ly2, top2, true /*with device cells*/);
 
-    std::map<unsigned int, const db::Region *> lmap;
-    lmap [ly2.insert_layer (db::LayerProperties (10, 0))] = l2n.layer_by_name ("psd");
-    lmap [ly2.insert_layer (db::LayerProperties (11, 0))] = l2n.layer_by_name ("nsd");
-    lmap [ly2.insert_layer (db::LayerProperties (12, 0))] = l2n.layer_by_name ("rbulk");
-    lmap [ly2.insert_layer (db::LayerProperties (13, 0))] = l2n.layer_by_name ("ptie");
-    lmap [ly2.insert_layer (db::LayerProperties (14, 0))] = l2n.layer_by_name ("ntie");
-    lmap [ly2.insert_layer (db::LayerProperties (1, 0)) ] = l2n.layer_by_name ("nwell");
-    lmap [ly2.insert_layer (db::LayerProperties (3, 0)) ] = l2n.layer_by_name ("poly");
-    lmap [ly2.insert_layer (db::LayerProperties (4, 0)) ] = l2n.layer_by_name ("diff_cont");
-    lmap [ly2.insert_layer (db::LayerProperties (5, 0)) ] = l2n.layer_by_name ("poly_cont");
-    lmap [ly2.insert_layer (db::LayerProperties (6, 0)) ] = l2n.layer_by_name ("metal1");
-    lmap [ly2.insert_layer (db::LayerProperties (7, 0)) ] = l2n.layer_by_name ("via1");
-    lmap [ly2.insert_layer (db::LayerProperties (8, 0)) ] = l2n.layer_by_name ("metal2");
+    std::map<unsigned int, unsigned int> lmap;
+    lmap [ly2.insert_layer (db::LayerProperties (10, 0))] = l2n.layer_index_by_name ("psd").value ();
+    lmap [ly2.insert_layer (db::LayerProperties (11, 0))] = l2n.layer_index_by_name ("nsd").value ();
+    lmap [ly2.insert_layer (db::LayerProperties (12, 0))] = l2n.layer_index_by_name ("rbulk").value ();
+    lmap [ly2.insert_layer (db::LayerProperties (13, 0))] = l2n.layer_index_by_name ("ptie").value ();
+    lmap [ly2.insert_layer (db::LayerProperties (14, 0))] = l2n.layer_index_by_name ("ntie").value ();
+    lmap [ly2.insert_layer (db::LayerProperties (1, 0)) ] = l2n.layer_index_by_name ("nwell").value ();
+    lmap [ly2.insert_layer (db::LayerProperties (3, 0)) ] = l2n.layer_index_by_name ("poly").value ();
+    lmap [ly2.insert_layer (db::LayerProperties (4, 0)) ] = l2n.layer_index_by_name ("diff_cont").value ();
+    lmap [ly2.insert_layer (db::LayerProperties (5, 0)) ] = l2n.layer_index_by_name ("poly_cont").value ();
+    lmap [ly2.insert_layer (db::LayerProperties (6, 0)) ] = l2n.layer_index_by_name ("metal1").value ();
+    lmap [ly2.insert_layer (db::LayerProperties (7, 0)) ] = l2n.layer_index_by_name ("via1").value ();
+    lmap [ly2.insert_layer (db::LayerProperties (8, 0)) ] = l2n.layer_index_by_name ("metal2").value ();
 
     l2n.build_all_nets (cm, ly2, lmap, "NET_", db::NPM_NoProperties, tl::Variant (), db::BNH_SubcircuitCells, "CIRCUIT_", "DEVICE_");
 
@@ -461,7 +461,7 @@ TEST(4_ReaderCombinedDevices)
 
     db::CellMapping cm = l2n.cell_mapping_into (ly2, top2, true /*with device cells*/);
 
-    std::map<unsigned int, const db::Region *> lmap = l2n.create_layermap (ly2, 1000);
+    std::map<unsigned int, unsigned int> lmap = l2n.create_layermap (ly2, 1000);
 
     l2n.build_all_nets (cm, ly2, lmap, "NET_", db::NPM_NoProperties, tl::Variant (), db::BNH_SubcircuitCells, "CIRCUIT_", "DEVICE_");
 
diff --git a/src/db/unit_tests/dbLayoutToNetlistTests.cc b/src/db/unit_tests/dbLayoutToNetlistTests.cc
index 8a00d69fe..6012110d9 100644
--- a/src/db/unit_tests/dbLayoutToNetlistTests.cc
+++ b/src/db/unit_tests/dbLayoutToNetlistTests.cc
@@ -386,15 +386,15 @@ TEST(1_BasicExtraction)
 
     db::CellMapping cm = l2n.cell_mapping_into (ly2, top2, true /*with device cells*/);
 
-    std::map<unsigned int, const db::Region *> lmap;
-    lmap [ly2.insert_layer (db::LayerProperties (10, 0))] = &rpsd;
-    lmap [ly2.insert_layer (db::LayerProperties (11, 0))] = &rnsd;
-    lmap [ly2.insert_layer (db::LayerProperties (3, 0)) ] = rpoly.get ();
-    lmap [ly2.insert_layer (db::LayerProperties (4, 0)) ] = rdiff_cont.get ();
-    lmap [ly2.insert_layer (db::LayerProperties (5, 0)) ] = rpoly_cont.get ();
-    lmap [ly2.insert_layer (db::LayerProperties (6, 0)) ] = rmetal1.get ();
-    lmap [ly2.insert_layer (db::LayerProperties (7, 0)) ] = rvia1.get ();
-    lmap [ly2.insert_layer (db::LayerProperties (8, 0)) ] = rmetal2.get ();
+    std::map<unsigned int, unsigned int> lmap;
+    lmap [ly2.insert_layer (db::LayerProperties (10, 0))] = l2n.layer_of (rpsd);
+    lmap [ly2.insert_layer (db::LayerProperties (11, 0))] = l2n.layer_of (rnsd);
+    lmap [ly2.insert_layer (db::LayerProperties (3, 0)) ] = l2n.layer_of (*rpoly);
+    lmap [ly2.insert_layer (db::LayerProperties (4, 0)) ] = l2n.layer_of (*rdiff_cont);
+    lmap [ly2.insert_layer (db::LayerProperties (5, 0)) ] = l2n.layer_of (*rpoly_cont);
+    lmap [ly2.insert_layer (db::LayerProperties (6, 0)) ] = l2n.layer_of (*rmetal1);
+    lmap [ly2.insert_layer (db::LayerProperties (7, 0)) ] = l2n.layer_of (*rvia1);
+    lmap [ly2.insert_layer (db::LayerProperties (8, 0)) ] = l2n.layer_of (*rmetal2);
 
     l2n.build_all_nets (cm, ly2, lmap, 0, db::NPM_NoProperties, tl::Variant (), db::BNH_Disconnected, 0, 0);
 
@@ -412,15 +412,15 @@ TEST(1_BasicExtraction)
 
     db::CellMapping cm = l2n.cell_mapping_into (ly2, top2, true /*with device cells*/);
 
-    std::map<unsigned int, const db::Region *> lmap;
-    lmap [ly2.insert_layer (db::LayerProperties (10, 0))] = &rpsd;
-    lmap [ly2.insert_layer (db::LayerProperties (11, 0))] = &rnsd;
-    lmap [ly2.insert_layer (db::LayerProperties (3, 0)) ] = rpoly.get ();
-    lmap [ly2.insert_layer (db::LayerProperties (4, 0)) ] = rdiff_cont.get ();
-    lmap [ly2.insert_layer (db::LayerProperties (5, 0)) ] = rpoly_cont.get ();
-    lmap [ly2.insert_layer (db::LayerProperties (6, 0)) ] = rmetal1.get ();
-    lmap [ly2.insert_layer (db::LayerProperties (7, 0)) ] = rvia1.get ();
-    lmap [ly2.insert_layer (db::LayerProperties (8, 0)) ] = rmetal2.get ();
+    std::map<unsigned int, unsigned int> lmap;
+    lmap [ly2.insert_layer (db::LayerProperties (10, 0))] = l2n.layer_of (rpsd);
+    lmap [ly2.insert_layer (db::LayerProperties (11, 0))] = l2n.layer_of (rnsd);
+    lmap [ly2.insert_layer (db::LayerProperties (3, 0)) ] = l2n.layer_of (*rpoly);
+    lmap [ly2.insert_layer (db::LayerProperties (4, 0)) ] = l2n.layer_of (*rdiff_cont);
+    lmap [ly2.insert_layer (db::LayerProperties (5, 0)) ] = l2n.layer_of (*rpoly_cont);
+    lmap [ly2.insert_layer (db::LayerProperties (6, 0)) ] = l2n.layer_of (*rmetal1);
+    lmap [ly2.insert_layer (db::LayerProperties (7, 0)) ] = l2n.layer_of (*rvia1);
+    lmap [ly2.insert_layer (db::LayerProperties (8, 0)) ] = l2n.layer_of (*rmetal2);
 
     l2n.build_all_nets (cm, ly2, lmap, "NET_", db::NPM_NoProperties, tl::Variant (), db::BNH_Disconnected, 0, 0);
 
@@ -438,15 +438,15 @@ TEST(1_BasicExtraction)
 
     db::CellMapping cm = l2n.cell_mapping_into (ly2, top2, true /*with device cells*/);
 
-    std::map<unsigned int, const db::Region *> lmap;
-    lmap [ly2.insert_layer (db::LayerProperties (10, 0))] = &rpsd;
-    lmap [ly2.insert_layer (db::LayerProperties (11, 0))] = &rnsd;
-    lmap [ly2.insert_layer (db::LayerProperties (3, 0)) ] = rpoly.get ();
-    lmap [ly2.insert_layer (db::LayerProperties (4, 0)) ] = rdiff_cont.get ();
-    lmap [ly2.insert_layer (db::LayerProperties (5, 0)) ] = rpoly_cont.get ();
-    lmap [ly2.insert_layer (db::LayerProperties (6, 0)) ] = rmetal1.get ();
-    lmap [ly2.insert_layer (db::LayerProperties (7, 0)) ] = rvia1.get ();
-    lmap [ly2.insert_layer (db::LayerProperties (8, 0)) ] = rmetal2.get ();
+    std::map<unsigned int, unsigned int> lmap;
+    lmap [ly2.insert_layer (db::LayerProperties (10, 0))] = l2n.layer_of (rpsd);
+    lmap [ly2.insert_layer (db::LayerProperties (11, 0))] = l2n.layer_of (rnsd);
+    lmap [ly2.insert_layer (db::LayerProperties (3, 0)) ] = l2n.layer_of (*rpoly);
+    lmap [ly2.insert_layer (db::LayerProperties (4, 0)) ] = l2n.layer_of (*rdiff_cont);
+    lmap [ly2.insert_layer (db::LayerProperties (5, 0)) ] = l2n.layer_of (*rpoly_cont);
+    lmap [ly2.insert_layer (db::LayerProperties (6, 0)) ] = l2n.layer_of (*rmetal1);
+    lmap [ly2.insert_layer (db::LayerProperties (7, 0)) ] = l2n.layer_of (*rvia1);
+    lmap [ly2.insert_layer (db::LayerProperties (8, 0)) ] = l2n.layer_of (*rmetal2);
 
     l2n.build_all_nets (cm, ly2, lmap, 0, db::NPM_NoProperties, tl::Variant (), db::BNH_SubcircuitCells, "CIRCUIT_", 0);
 
@@ -464,15 +464,15 @@ TEST(1_BasicExtraction)
 
     db::CellMapping cm = l2n.cell_mapping_into (ly2, top2, true /*with device cells*/);
 
-    std::map<unsigned int, const db::Region *> lmap;
-    lmap [ly2.insert_layer (db::LayerProperties (10, 0))] = &rpsd;
-    lmap [ly2.insert_layer (db::LayerProperties (11, 0))] = &rnsd;
-    lmap [ly2.insert_layer (db::LayerProperties (3, 0)) ] = rpoly.get ();
-    lmap [ly2.insert_layer (db::LayerProperties (4, 0)) ] = rdiff_cont.get ();
-    lmap [ly2.insert_layer (db::LayerProperties (5, 0)) ] = rpoly_cont.get ();
-    lmap [ly2.insert_layer (db::LayerProperties (6, 0)) ] = rmetal1.get ();
-    lmap [ly2.insert_layer (db::LayerProperties (7, 0)) ] = rvia1.get ();
-    lmap [ly2.insert_layer (db::LayerProperties (8, 0)) ] = rmetal2.get ();
+    std::map<unsigned int, unsigned int> lmap;
+    lmap [ly2.insert_layer (db::LayerProperties (10, 0))] = l2n.layer_of (rpsd);
+    lmap [ly2.insert_layer (db::LayerProperties (11, 0))] = l2n.layer_of (rnsd);
+    lmap [ly2.insert_layer (db::LayerProperties (3, 0)) ] = l2n.layer_of (*rpoly);
+    lmap [ly2.insert_layer (db::LayerProperties (4, 0)) ] = l2n.layer_of (*rdiff_cont);
+    lmap [ly2.insert_layer (db::LayerProperties (5, 0)) ] = l2n.layer_of (*rpoly_cont);
+    lmap [ly2.insert_layer (db::LayerProperties (6, 0)) ] = l2n.layer_of (*rmetal1);
+    lmap [ly2.insert_layer (db::LayerProperties (7, 0)) ] = l2n.layer_of (*rvia1);
+    lmap [ly2.insert_layer (db::LayerProperties (8, 0)) ] = l2n.layer_of (*rmetal2);
 
     l2n.build_all_nets (cm, ly2, lmap, 0, db::NPM_AllProperties, tl::Variant (42), db::BNH_Flatten, 0, 0);
 
@@ -490,15 +490,15 @@ TEST(1_BasicExtraction)
 
     db::CellMapping cm = l2n.cell_mapping_into (ly2, top2, true /*with device cells*/);
 
-    std::map<unsigned int, const db::Region *> lmap;
-    lmap [ly2.insert_layer (db::LayerProperties (10, 0))] = &rpsd;
-    lmap [ly2.insert_layer (db::LayerProperties (11, 0))] = &rnsd;
-    lmap [ly2.insert_layer (db::LayerProperties (3, 0)) ] = rpoly.get ();
-    lmap [ly2.insert_layer (db::LayerProperties (4, 0)) ] = rdiff_cont.get ();
-    lmap [ly2.insert_layer (db::LayerProperties (5, 0)) ] = rpoly_cont.get ();
-    lmap [ly2.insert_layer (db::LayerProperties (6, 0)) ] = rmetal1.get ();
-    lmap [ly2.insert_layer (db::LayerProperties (7, 0)) ] = rvia1.get ();
-    lmap [ly2.insert_layer (db::LayerProperties (8, 0)) ] = rmetal2.get ();
+    std::map<unsigned int, unsigned int> lmap;
+    lmap [ly2.insert_layer (db::LayerProperties (10, 0))] = l2n.layer_of (rpsd);
+    lmap [ly2.insert_layer (db::LayerProperties (11, 0))] = l2n.layer_of (rnsd);
+    lmap [ly2.insert_layer (db::LayerProperties (3, 0)) ] = l2n.layer_of (*rpoly);
+    lmap [ly2.insert_layer (db::LayerProperties (4, 0)) ] = l2n.layer_of (*rdiff_cont);
+    lmap [ly2.insert_layer (db::LayerProperties (5, 0)) ] = l2n.layer_of (*rpoly_cont);
+    lmap [ly2.insert_layer (db::LayerProperties (6, 0)) ] = l2n.layer_of (*rmetal1);
+    lmap [ly2.insert_layer (db::LayerProperties (7, 0)) ] = l2n.layer_of (*rvia1);
+    lmap [ly2.insert_layer (db::LayerProperties (8, 0)) ] = l2n.layer_of (*rmetal2);
 
     l2n.build_all_nets (cm, ly2, lmap, 0, db::NPM_AllProperties, tl::Variant (42), db::BNH_SubcircuitCells, "CIRCUIT_", 0);
 
@@ -516,15 +516,15 @@ TEST(1_BasicExtraction)
 
     db::CellMapping cm = l2n.cell_mapping_into (ly2, top2, true /*with device cells*/);
 
-    std::map<unsigned int, const db::Region *> lmap;
-    lmap [ly2.insert_layer (db::LayerProperties (10, 0))] = &rpsd;
-    lmap [ly2.insert_layer (db::LayerProperties (11, 0))] = &rnsd;
-    lmap [ly2.insert_layer (db::LayerProperties (3, 0)) ] = rpoly.get ();
-    lmap [ly2.insert_layer (db::LayerProperties (4, 0)) ] = rdiff_cont.get ();
-    lmap [ly2.insert_layer (db::LayerProperties (5, 0)) ] = rpoly_cont.get ();
-    lmap [ly2.insert_layer (db::LayerProperties (6, 0)) ] = rmetal1.get ();
-    lmap [ly2.insert_layer (db::LayerProperties (7, 0)) ] = rvia1.get ();
-    lmap [ly2.insert_layer (db::LayerProperties (8, 0)) ] = rmetal2.get ();
+    std::map<unsigned int, unsigned int> lmap;
+    lmap [ly2.insert_layer (db::LayerProperties (10, 0))] = l2n.layer_of (rpsd);
+    lmap [ly2.insert_layer (db::LayerProperties (11, 0))] = l2n.layer_of (rnsd);
+    lmap [ly2.insert_layer (db::LayerProperties (3, 0)) ] = l2n.layer_of (*rpoly);
+    lmap [ly2.insert_layer (db::LayerProperties (4, 0)) ] = l2n.layer_of (*rdiff_cont);
+    lmap [ly2.insert_layer (db::LayerProperties (5, 0)) ] = l2n.layer_of (*rpoly_cont);
+    lmap [ly2.insert_layer (db::LayerProperties (6, 0)) ] = l2n.layer_of (*rmetal1);
+    lmap [ly2.insert_layer (db::LayerProperties (7, 0)) ] = l2n.layer_of (*rvia1);
+    lmap [ly2.insert_layer (db::LayerProperties (8, 0)) ] = l2n.layer_of (*rmetal2);
 
     l2n.build_all_nets (cm, ly2, lmap, "NET_", db::NPM_NoProperties, tl::Variant (), db::BNH_SubcircuitCells, "CIRCUIT_", "DEVICE_");
 
@@ -627,15 +627,15 @@ TEST(1_BasicExtraction)
 
     db::CellMapping cm = l2n.cell_mapping_into (ly2, top2, true /*with device cells*/);
 
-    std::map<unsigned int, const db::Region *> lmap;
-    lmap [ly2.insert_layer (db::LayerProperties (10, 0))] = &rpsd;
-    lmap [ly2.insert_layer (db::LayerProperties (11, 0))] = &rnsd;
-    lmap [ly2.insert_layer (db::LayerProperties (3, 0)) ] = rpoly.get ();
-    lmap [ly2.insert_layer (db::LayerProperties (4, 0)) ] = rdiff_cont.get ();
-    lmap [ly2.insert_layer (db::LayerProperties (5, 0)) ] = rpoly_cont.get ();
-    lmap [ly2.insert_layer (db::LayerProperties (6, 0)) ] = rmetal1.get ();
-    lmap [ly2.insert_layer (db::LayerProperties (7, 0)) ] = rvia1.get ();
-    lmap [ly2.insert_layer (db::LayerProperties (8, 0)) ] = rmetal2.get ();
+    std::map<unsigned int, unsigned int> lmap;
+    lmap [ly2.insert_layer (db::LayerProperties (10, 0))] = l2n.layer_of (rpsd);
+    lmap [ly2.insert_layer (db::LayerProperties (11, 0))] = l2n.layer_of (rnsd);
+    lmap [ly2.insert_layer (db::LayerProperties (3, 0)) ] = l2n.layer_of (*rpoly);
+    lmap [ly2.insert_layer (db::LayerProperties (4, 0)) ] = l2n.layer_of (*rdiff_cont);
+    lmap [ly2.insert_layer (db::LayerProperties (5, 0)) ] = l2n.layer_of (*rpoly_cont);
+    lmap [ly2.insert_layer (db::LayerProperties (6, 0)) ] = l2n.layer_of (*rmetal1);
+    lmap [ly2.insert_layer (db::LayerProperties (7, 0)) ] = l2n.layer_of (*rvia1);
+    lmap [ly2.insert_layer (db::LayerProperties (8, 0)) ] = l2n.layer_of (*rmetal2);
 
     l2n.build_all_nets (cm, ly2, lmap, "NET_", db::NPM_NoProperties, tl::Variant (), db::BNH_SubcircuitCells, "CIRCUIT_", "DEVICE_");
 
diff --git a/src/db/unit_tests/dbLayoutToNetlistWriterTests.cc b/src/db/unit_tests/dbLayoutToNetlistWriterTests.cc
index 70325f6ef..fa9d305a8 100644
--- a/src/db/unit_tests/dbLayoutToNetlistWriterTests.cc
+++ b/src/db/unit_tests/dbLayoutToNetlistWriterTests.cc
@@ -197,15 +197,15 @@ TEST(1_WriterBasic)
 
     db::CellMapping cm = l2n.cell_mapping_into (ly2, top2, true /*with device cells*/);
 
-    std::map<unsigned int, const db::Region *> lmap;
-    lmap [ly2.insert_layer (db::LayerProperties (10, 0))] = &rpsd;
-    lmap [ly2.insert_layer (db::LayerProperties (11, 0))] = &rnsd;
-    lmap [ly2.insert_layer (db::LayerProperties (3, 0)) ] = rpoly.get ();
-    lmap [ly2.insert_layer (db::LayerProperties (4, 0)) ] = rdiff_cont.get ();
-    lmap [ly2.insert_layer (db::LayerProperties (5, 0)) ] = rpoly_cont.get ();
-    lmap [ly2.insert_layer (db::LayerProperties (6, 0)) ] = rmetal1.get ();
-    lmap [ly2.insert_layer (db::LayerProperties (7, 0)) ] = rvia1.get ();
-    lmap [ly2.insert_layer (db::LayerProperties (8, 0)) ] = rmetal2.get ();
+    std::map<unsigned int, unsigned int> lmap;
+    lmap [ly2.insert_layer (db::LayerProperties (10, 0))] = l2n.layer_of (rpsd);
+    lmap [ly2.insert_layer (db::LayerProperties (11, 0))] = l2n.layer_of (rnsd);
+    lmap [ly2.insert_layer (db::LayerProperties (3, 0)) ] = l2n.layer_of (*rpoly);
+    lmap [ly2.insert_layer (db::LayerProperties (4, 0)) ] = l2n.layer_of (*rdiff_cont);
+    lmap [ly2.insert_layer (db::LayerProperties (5, 0)) ] = l2n.layer_of (*rpoly_cont);
+    lmap [ly2.insert_layer (db::LayerProperties (6, 0)) ] = l2n.layer_of (*rmetal1);
+    lmap [ly2.insert_layer (db::LayerProperties (7, 0)) ] = l2n.layer_of (*rvia1);
+    lmap [ly2.insert_layer (db::LayerProperties (8, 0)) ] = l2n.layer_of (*rmetal2);
 
     l2n.build_all_nets (cm, ly2, lmap, "NET_", db::NPM_NoProperties, tl::Variant (), db::BNH_Disconnected, 0, "DEVICE_");
 
@@ -426,19 +426,19 @@ TEST(2_WriterWithGlobalNets)
 
     db::CellMapping cm = l2n.cell_mapping_into (ly2, top2, true /*with device cells*/);
 
-    std::map<unsigned int, const db::Region *> lmap;
-    lmap [ly2.insert_layer (db::LayerProperties (10, 0))] = &rpsd;
-    lmap [ly2.insert_layer (db::LayerProperties (11, 0))] = &rnsd;
-    lmap [ly2.insert_layer (db::LayerProperties (12, 0))] = rbulk.get ();
-    lmap [ly2.insert_layer (db::LayerProperties (13, 0))] = &rptie;
-    lmap [ly2.insert_layer (db::LayerProperties (14, 0))] = &rntie;
-    lmap [ly2.insert_layer (db::LayerProperties (1, 0)) ] = rnwell.get ();
-    lmap [ly2.insert_layer (db::LayerProperties (3, 0)) ] = rpoly.get ();
-    lmap [ly2.insert_layer (db::LayerProperties (4, 0)) ] = rdiff_cont.get ();
-    lmap [ly2.insert_layer (db::LayerProperties (5, 0)) ] = rpoly_cont.get ();
-    lmap [ly2.insert_layer (db::LayerProperties (6, 0)) ] = rmetal1.get ();
-    lmap [ly2.insert_layer (db::LayerProperties (7, 0)) ] = rvia1.get ();
-    lmap [ly2.insert_layer (db::LayerProperties (8, 0)) ] = rmetal2.get ();
+    std::map<unsigned int, unsigned int> lmap;
+    lmap [ly2.insert_layer (db::LayerProperties (10, 0))] = l2n.layer_of (rpsd);
+    lmap [ly2.insert_layer (db::LayerProperties (11, 0))] = l2n.layer_of (rnsd);
+    lmap [ly2.insert_layer (db::LayerProperties (12, 0))] = l2n.layer_of (*rbulk);
+    lmap [ly2.insert_layer (db::LayerProperties (13, 0))] = l2n.layer_of (rptie);
+    lmap [ly2.insert_layer (db::LayerProperties (14, 0))] = l2n.layer_of (rntie);
+    lmap [ly2.insert_layer (db::LayerProperties (1, 0)) ] = l2n.layer_of (*rnwell);
+    lmap [ly2.insert_layer (db::LayerProperties (3, 0)) ] = l2n.layer_of (*rpoly);
+    lmap [ly2.insert_layer (db::LayerProperties (4, 0)) ] = l2n.layer_of (*rdiff_cont);
+    lmap [ly2.insert_layer (db::LayerProperties (5, 0)) ] = l2n.layer_of (*rpoly_cont);
+    lmap [ly2.insert_layer (db::LayerProperties (6, 0)) ] = l2n.layer_of (*rmetal1);
+    lmap [ly2.insert_layer (db::LayerProperties (7, 0)) ] = l2n.layer_of (*rvia1);
+    lmap [ly2.insert_layer (db::LayerProperties (8, 0)) ] = l2n.layer_of (*rmetal2);
 
     l2n.build_all_nets (cm, ly2, lmap, "NET_", db::NPM_NoProperties, tl::Variant (), db::BNH_SubcircuitCells, "CIRCUIT_", "DEVICE_");
 
diff --git a/src/layui/layui/layNetlistBrowserPage.cc b/src/layui/layui/layNetlistBrowserPage.cc
index fd3f4d938..ce725e086 100644
--- a/src/layui/layui/layNetlistBrowserPage.cc
+++ b/src/layui/layui/layNetlistBrowserPage.cc
@@ -1858,7 +1858,7 @@ NetlistBrowserPage::export_nets (const std::vector<const db::Net *> *nets)
       cm = database->cell_mapping_into (target_layout, target_layout.cell (target_top_index), *nets);
     }
 
-    std::map<unsigned int, const db::Region *> lm = database->create_layermap (target_layout, dialog->start_layer_number ());
+    std::map<unsigned int, unsigned int> lm = database->create_layermap (target_layout, dialog->start_layer_number ());
 
     database->build_nets (nets, cm, target_layout, lm,
                           dialog->net_prefix ().empty () ? 0 : dialog->net_prefix ().c_str (),