diff --git a/CMakeLists.txt b/CMakeLists.txt
index 0d84e9b5..6a4c4a50 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -200,6 +200,7 @@ set(STA_SOURCE
   util/Debug.cc
   util/Error.cc
   util/Fuzzy.cc
+  util/Hash.cc
   util/Machine.cc
   util/MinMax.cc
   util/PatternMatch.cc
diff --git a/doc/OpenSTA.odt b/doc/OpenSTA.odt
index cb48d45f..80786bdd 100644
Binary files a/doc/OpenSTA.odt and b/doc/OpenSTA.odt differ
diff --git a/liberty/EquivCells.cc b/liberty/EquivCells.cc
index 43f9730c..f0ef2726 100644
--- a/liberty/EquivCells.cc
+++ b/liberty/EquivCells.cc
@@ -15,6 +15,7 @@
 // along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 #include "Machine.hh"
+#include "Hash.hh"
 #include "PortDirection.hh"
 #include "Transition.hh"
 #include "MinMax.hh"
@@ -40,8 +41,6 @@ static unsigned
 hashFuncExpr(const FuncExpr *expr);
 static unsigned
 hashPort(const LibertyPort *port);
-static unsigned
-hashString(const char *str);
 
 static float
 cellDriveResistance(const LibertyCell *cell)
@@ -228,17 +227,6 @@ hashFuncExpr(const FuncExpr *expr)
   }
 }
 
-static unsigned
-hashString(const char *str)
-{
-  unsigned hash = 0;
-  size_t length = strlen(str);
-  for (size_t i = 0; i < length; i++) {
-    hash = str[i] + (hash << 2);
-  }
-  return hash;
-}
-
 bool
 equivCells(const LibertyCell *cell1,
 	   const LibertyCell *cell2)
diff --git a/liberty/LibertyReader.cc b/liberty/LibertyReader.cc
index 7ae3c6ae..289dd39e 100644
--- a/liberty/LibertyReader.cc
+++ b/liberty/LibertyReader.cc
@@ -172,6 +172,7 @@ LibertyReader::defineVisitors()
   defineAttrVisitor("voltage_unit", &LibertyReader::visitVoltageUnit);
   defineAttrVisitor("current_unit", &LibertyReader::visitCurrentUnit);
   defineAttrVisitor("leakage_power_unit", &LibertyReader::visitPowerUnit);
+  defineAttrVisitor("distance_unit", &LibertyReader::visitDistanceUnit);
   defineAttrVisitor("delay_model", &LibertyReader::visitDelayModel);
   defineAttrVisitor("bus_naming_style", &LibertyReader::visitBusStyle);
   defineAttrVisitor("voltage_map", &LibertyReader::visitVoltageMap);
@@ -547,17 +548,20 @@ LibertyReader::beginLibrary(LibertyGroup *group)
     // 1v default
     volt_scale_ = 1;
     // Default is 1mA.
-    curr_scale_ = 1E-3F;
+    current_scale_ = 1E-3F;
     // Default is 1;
     power_scale_ = 1;
     // Default is fJ.
     setEnergyScale();
+    // Default is 1 micron.
+    distance_scale_ = 1e-6;
 
     library_->units()->timeUnit()->setScale(time_scale_);
     library_->units()->capacitanceUnit()->setScale(cap_scale_);
     library_->units()->resistanceUnit()->setScale(res_scale_);
     library_->units()->voltageUnit()->setScale(volt_scale_);
-    library_->units()->currentUnit()->setScale(curr_scale_);
+    library_->units()->currentUnit()->setScale(current_scale_);
+    library_->units()->distanceUnit()->setScale(distance_scale_);
 
 
     library_->setDelayModelType(DelayModelType::cmos_linear);
@@ -667,7 +671,7 @@ void
 LibertyReader::visitCurrentUnit(LibertyAttr *attr)
 {
   if (library_)
-    parseUnits(attr, "A", curr_scale_, library_->units()->currentUnit());
+    parseUnits(attr, "A", current_scale_, library_->units()->currentUnit());
 }
 
 void
@@ -685,6 +689,13 @@ LibertyReader::visitPowerUnit(LibertyAttr *attr)
     parseUnits(attr, "W", power_scale_, library_->units()->powerUnit());
 }
 
+void
+LibertyReader::visitDistanceUnit(LibertyAttr *attr)
+{
+  if (library_)
+    parseUnits(attr, "m", distance_scale_, library_->units()->distanceUnit());
+}
+
 void
 LibertyReader::parseUnits(LibertyAttr *attr,
 			  const char *unit_suffix,
diff --git a/liberty/LibertyReaderPvt.hh b/liberty/LibertyReaderPvt.hh
index ecdc42ac..cb273492 100644
--- a/liberty/LibertyReaderPvt.hh
+++ b/liberty/LibertyReaderPvt.hh
@@ -81,6 +81,7 @@ public:
   virtual void visitVoltageUnit(LibertyAttr *attr);
   virtual void visitCurrentUnit(LibertyAttr *attr);
   virtual void visitPowerUnit(LibertyAttr *attr);
+  virtual void visitDistanceUnit(LibertyAttr *attr);
   virtual void parseUnits(LibertyAttr *attr,
 			  const char *suffix,
 			  float &scale_var,
@@ -562,9 +563,10 @@ protected:
   float cap_scale_;
   float res_scale_;
   float volt_scale_;
-  float curr_scale_;
+  float current_scale_;
   float power_scale_;
   float energy_scale_;
+  float distance_scale_;
   bool have_resistance_unit_;
 
 private:
diff --git a/tcl/Sdc.tcl b/tcl/Sdc.tcl
index c9ac24c0..ad0312f6 100644
--- a/tcl/Sdc.tcl
+++ b/tcl/Sdc.tcl
@@ -191,22 +191,23 @@ proc check_path_divider { divider } {
 
 define_cmd_args "set_units" \
   {[-capacitance cap_unit] [-resistance res_unit] [-time time_unit]\
-     [-voltage voltage_unit] [-current current_unit] [-power power_unit]}
+     [-voltage voltage_unit] [-current current_unit] [-power power_unit]\
+     [-distance distance_unit]}
 
-# Note that this does NOT actually set the units.
-# It merely checks that the library units are the same as the
-# units in the set_units command.
+# Note that the set_units command does NOT actually set the units.
+# It merely checks that the current units are the same as the
+# units in the set_units command. Blame SNPS for this brain damage.
 proc set_units { args } {
   parse_key_args "set_units" args \
-    keys {-capacitance -resistance -time -voltage -current -power} flags {}
-  if { [llength $args] != 0 } {
-    cmd_usage_error "set_units"
-  }
+    keys {-capacitance -resistance -time -voltage -current -power -distance} \
+    flags {}
+  check_argc_eq0 "set_units" $args
   check_unit "capacitance" -capacitance "f" keys
   check_unit "time" -time "s" keys
   check_unit "voltage" -voltage "v" keys
   check_unit "current" -current "A" keys
   check_unit "resistance" -resistance "ohm" keys
+  check_unit "distance" -distance "m" keys
 }
 
 proc check_unit { unit key unit_name key_var } {
@@ -219,23 +220,8 @@ proc check_unit { unit key unit_name key_var } {
       set prefix [string index $value 0]
       set suffix [string range $value 1 end]
       if { [string equal -nocase $suffix $unit_name] } {
-	if { [string equal $prefix "M"] } {
-	  check_unit_scale $unit 1E+6
-	} elseif { [string equal $prefix "k"] } {
-	  check_unit_scale $unit 1E+3
-	} elseif { [string equal $prefix "m"] } {
-	  check_unit_scale $unit 1E-3
-	} elseif { [string equal $prefix "u"] } {
-	  check_unit_scale $unit 1E-6
-	} elseif { [string equal $prefix "n"] } {
-	  check_unit_scale $unit 1E-9
-	} elseif { [string equal $prefix "p"] } {
-	  check_unit_scale $unit 1E-12
-	} elseif { [string equal $prefix "f"] } {
-	  check_unit_scale $unit 1E-15
-	} else {
-	  sta_error "unknown $unit prefix '$prefix'."
-	}
+	set scale [unit_prefix_scale $unit $prefix]
+	check_unit_scale $unit 1.0 $scale
       } else {
 	sta_error "unknown unit $unit '$suffix'."
       }
@@ -243,6 +229,26 @@ proc check_unit { unit key unit_name key_var } {
   }
 }
 
+proc unit_prefix_scale { unit prefix } {
+  if { [string equal $prefix "M"] } {
+    return 1E+6
+  } elseif { [string equal $prefix "k"] } {
+    return 1E+3
+  } elseif { [string equal $prefix "m"] } {
+    return 1E-3
+  } elseif { [string equal $prefix "u"] } {
+    return 1E-6
+  } elseif { [string equal $prefix "n"] } {
+    return 1E-9
+  } elseif { [string equal $prefix "p"] } {
+    return 1E-12
+  } elseif { [string equal $prefix "f"] } {
+    return 1E-15
+  } else {
+    sta_error "unknown $unit prefix '$prefix'."
+  }
+}
+
 proc check_unit_scale { unit scale } {
   set unit_scale [unit_scale $unit]
   if { ![fuzzy_equal $scale $unit_scale] } {
@@ -250,6 +256,53 @@ proc check_unit_scale { unit scale } {
   }
 }
 
+################################################################
+
+define_cmd_args "set_cmd_units" \
+  {[-capacitance cap_unit] [-resistance res_unit] [-time time_unit]\
+     [-voltage voltage_unit] [-current current_unit] [-power power_unit]\
+     [-distance distance_unit]}
+
+proc set_cmd_units { args } {
+  parse_key_args "set_cmd_units" args \
+    keys {-capacitance -resistance -time -voltage -current -power \
+	    -distance -digits -suffix} \
+    flags {}
+
+  check_argc_eq0 "set_cmd_units" $args
+  set_unit_values "capacitance" -capacitance "f" keys
+  set_unit_values "time" -time "s" keys
+  set_unit_values "voltage" -voltage "v" keys
+  set_unit_values "current" -current "A" keys
+  set_unit_values "resistance" -resistance "ohm" keys
+  set_unit_values "distance" -distance "m" keys
+}
+
+proc set_unit_values { unit key unit_name key_var } {
+  upvar 1 $key_var keys
+  if { [info exists keys($key)] } {
+    set value $keys($key)
+    if { [string equal -nocase $value $unit_name] } {
+      set_cmd_unit_scale $unit 1.0
+    } else {
+      set prefix [string index $value 0]
+      set suffix [string range $value 1 end]
+      if { [string equal -nocase $suffix $unit_name] } {
+	set scale [unit_prefix_scale $unit $prefix]
+	set_cmd_unit_scale $unit $scale
+      } else {
+	sta_error "unknown $unit unit '$suffix'."
+      }
+    }
+    if [info exists keys(-digits)] {
+      set_cmd_unit_digits $unit $keys(-digits)
+    }
+    if [info exists keys(-suffix)] {
+      set_cmd_unit_suffix $unit $keys(-suffix)
+    }
+  }
+}
+
 ################################################################
 #
 # Object Access Commands
diff --git a/tcl/StaTcl.i b/tcl/StaTcl.i
index 37085132..d4f9a29c 100644
--- a/tcl/StaTcl.i
+++ b/tcl/StaTcl.i
@@ -3808,6 +3808,8 @@ format_power(const char *value,
   return Sta::sta()->units()->powerUnit()->asString(value1, digits);
 }
 
+////////////////////////////////////////////////////////////////
+
 // Unit converstion from sta unit to user interface and visa versa.
 double
 time_ui_sta(double value)
@@ -3881,6 +3883,50 @@ power_sta_ui(double value)
   return value / Sta::sta()->units()->powerUnit()->scale();
 }
 
+double
+distance_ui_sta(double value)
+{
+  return value * Sta::sta()->units()->distanceUnit()->scale();
+}
+
+double
+distance_sta_ui(double value)
+{
+  return value / Sta::sta()->units()->distanceUnit()->scale();
+}
+
+////////////////////////////////////////////////////////////////
+
+void
+set_cmd_unit_scale(const char *unit_name,
+		   float scale)
+{
+  Unit *unit = Sta::sta()->units()->find(unit_name);
+  if (unit)
+    unit->setScale(scale);
+}
+
+void
+set_cmd_unit_digits(const char *unit_name,
+		    int digits)
+{
+  Unit *unit = Sta::sta()->units()->find(unit_name);
+  if (unit)
+    unit->setDigits(digits);
+}
+
+void
+set_cmd_unit_suffix(const char *unit_name,
+		    const char *suffix)
+{
+  Unit *unit = Sta::sta()->units()->find(unit_name);
+  if (unit) {
+    unit->setSuffix(suffix);
+  }
+}
+
+////////////////////////////////////////////////////////////////
+
 VertexIterator *
 vertex_iterator()
 {
diff --git a/util/Hash.cc b/util/Hash.cc
new file mode 100644
index 00000000..78b54013
--- /dev/null
+++ b/util/Hash.cc
@@ -0,0 +1,33 @@
+// OpenSTA, Static Timing Analyzer
+// Copyright (c) 2019, Parallax Software, Inc.
+// 
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+// 
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+// 
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+#include <string.h>
+#include "Machine.hh"
+#include "Hash.hh"
+
+namespace sta {
+
+Hash
+hashString(const char *str)
+{
+  unsigned hash = hash_init_value;
+  size_t length = strlen(str);
+  for (size_t i = 0; i < length; i++)
+    hash = ((hash << 5) + hash) ^ str[i];
+  return hash;
+}
+
+} // namespace
diff --git a/util/Hash.hh b/util/Hash.hh
index ffb13b7e..f1c702fd 100644
--- a/util/Hash.hh
+++ b/util/Hash.hh
@@ -48,5 +48,9 @@ nextMersenne(size_t n)
   return (n + 1) * 2 - 1;
 }
 
+// Sadly necessary until c++ std::hash works for char *.
+Hash
+hashString(const char *str);
+
 } // namespace
 #endif