diff --git a/doc/OpenSTA.odt b/doc/OpenSTA.odt
index 6fc4c047..c445ecd0 100644
Binary files a/doc/OpenSTA.odt and b/doc/OpenSTA.odt differ
diff --git a/doc/OpenSTA.pdf b/doc/OpenSTA.pdf
index 5750f166..f69ea92a 100644
Binary files a/doc/OpenSTA.pdf and b/doc/OpenSTA.pdf differ
diff --git a/sdc/Sdc.tcl b/sdc/Sdc.tcl
index 91f41727..18d3e6fb 100644
--- a/sdc/Sdc.tcl
+++ b/sdc/Sdc.tcl
@@ -408,25 +408,22 @@ proc current_design { {design ""} } {
 
 # Generic get_* filter.
 proc filter_objs { filter objects filter_function object_type } {
-  set filter_regexp1 {@?([a-zA-Z_]+) *(==|!=|=~|!~) *([0-9a-zA-Z_\*]+)}
+  set filter_regexp1 {@?([a-zA-Z_]+) *((==|!=|=~|!~) *([0-9a-zA-Z_\*]+))?}
   set filter_or_regexp "($filter_regexp1) *\\|\\| *($filter_regexp1)"
   set filter_and_regexp "($filter_regexp1) *&& *($filter_regexp1)"
   set filtered_objects {}
   # Ignore sub-exprs in filter_regexp1 for expr2 match var.
-  if { [regexp $filter_or_regexp $filter ignore expr1 \
-	  ignore ignore ignore expr2] } {
-    regexp $filter_regexp1 $expr1 ignore attr_name op arg
-    set filtered_objects1 [$filter_function $attr_name $op $arg $objects]
-    regexp $filter_regexp1 $expr2 ignore attr_name op arg
-    set filtered_objects2 [$filter_function $attr_name $op $arg $objects]
+  if { [regexp $filter_or_regexp $filter ignore expr1 ignore ignore ignore ignore expr2] } {
+    set filtered_objects1 [filter_objs $expr1 $objects $filter_function $object_type]
+    set filtered_objects2 [filter_objs $expr2 $objects $filter_function $object_type]
     set filtered_objects [concat $filtered_objects1 $filtered_objects2]
-  } elseif { [regexp $filter_and_regexp $filter ignore expr1 \
-		ignore ignore ignore expr2] } {
-    regexp $filter_regexp1 $expr1 ignore attr_name op arg
-    set filtered_objects [$filter_function $attr_name $op $arg $objects]
-    regexp $filter_regexp1 $expr2 ignore attr_name op arg
-    set filtered_objects [$filter_function $attr_name $op $arg $filtered_objects]
-  } elseif { [regexp $filter_regexp1 $filter ignore attr_name op arg] } {
+  } elseif { [regexp $filter_and_regexp $filter ignore expr1 ignore ignore ignore ignore expr2] } {
+    set filtered_objects [filter_objs $expr1 $objects $filter_function $object_type]
+    set filtered_objects [filter_objs $expr2 $filtered_objects $filter_function $object_type]
+  } elseif { [regexp $filter_regexp1 $filter ignore attr_name ignore op arg] } {
+    # If no op/arg, use <attr_name>==1 by default.
+    set op [expr {($op == "") ? "==" : $op}]
+    set arg [expr {($arg == "") ? "1" : $arg}]
     set filtered_objects [$filter_function $attr_name $op $arg $objects]
   } else {
     sta_error 350 "unsupported $object_type -filter expression."
diff --git a/test/get_filter.ok b/test/get_filter.ok
index 7b1ee120..8e98cdba 100644
--- a/test/get_filter.ok
+++ b/test/get_filter.ok
@@ -1,25 +1,34 @@
-get_cells
+[get_cells -filter liberty_cell==BUFx2_ASAP7_75t_R *]
 u1
-get_clocks
+[get_clocks -filter is_virtual==0 *]
 clk
-get_clocks 2
+[get_clocks -filter is_virtual==1 *]
 vclk
-get_lib_cells
+[get_clocks -filter is_virtual *]
+vclk
+[get_clocks -filter is_virtual&&is_generated *]
+[get_clocks -filter is_virtual&&is_generated==0 *]
+vclk
+[get_clocks -filter is_virtual||is_generated *]
+vclk
+[get_clocks -filter is_virtual==0||is_generated *]
+clk
+[get_lib_cells -filter is_buffer==1 *]
 asap7_small/BUFx2_ASAP7_75t_R
-get_lib_cells 2
+[get_lib_cells -filter is_inverter==0 *]
 asap7_small/AND2x2_ASAP7_75t_R
 asap7_small/BUFx2_ASAP7_75t_R
 asap7_small/DFFHQx4_ASAP7_75t_R
-get_lib_pins
+[get_lib_pins -filter direction==input BUFx2_ASAP7_75t_R/*]
 A
-get_lib_pins 2
+[get_lib_pins -filter direction==output BUFx2_ASAP7_75t_R/*]
 Y
-get_libs
+[get_libs -filter name==asap7_small *]
 asap7_small
-get_nets
+[get_nets -filter name=~*q *]
 r1q
 r2q
-get_pins
+[get_pins -filter direction==input *]
 r1/CLK
 r1/D
 r2/CLK
@@ -29,17 +38,17 @@ r3/D
 u1/A
 u2/A
 u2/B
-get_pins 2
+[get_pins -filter direction==output *]
 r1/Q
 r2/Q
 r3/Q
 u1/Y
 u2/Y
-get_ports
+[get_ports -filter direction==input *]
 clk1
 clk2
 clk3
 in1
 in2
-get_ports 2
+[get_ports -filter direction==output *]
 out
diff --git a/test/get_filter.tcl b/test/get_filter.tcl
index 23c4b400..e3269754 100644
--- a/test/get_filter.tcl
+++ b/test/get_filter.tcl
@@ -6,29 +6,39 @@ create_clock -name clk -period 500 {clk1 clk2 clk3}
 create_clock -name vclk -period 1000
 
 # Test filters for each SDC command
-puts "get_cells"
+puts {[get_cells -filter liberty_cell==BUFx2_ASAP7_75t_R *]}
 report_object_full_names [get_cells -filter liberty_cell==BUFx2_ASAP7_75t_R *]
-puts "get_clocks"
+puts {[get_clocks -filter is_virtual==0 *]}
 report_object_full_names [get_clocks -filter is_virtual==0 *]
-puts "get_clocks 2"
+puts {[get_clocks -filter is_virtual==1 *]}
 report_object_full_names [get_clocks -filter is_virtual==1 *]
-puts "get_lib_cells"
+puts {[get_clocks -filter is_virtual *]}
+report_object_full_names [get_clocks -filter is_virtual *]
+puts {[get_clocks -filter is_virtual&&is_generated *]}
+report_object_full_names [get_clocks -filter is_virtual&&is_generated *]
+puts {[get_clocks -filter is_virtual&&is_generated==0 *]}
+report_object_full_names [get_clocks -filter is_virtual&&is_generated==0 *]
+puts {[get_clocks -filter is_virtual||is_generated *]}
+report_object_full_names [get_clocks -filter is_virtual||is_generated *]
+puts {[get_clocks -filter is_virtual==0||is_generated *]}
+report_object_full_names [get_clocks -filter is_virtual==0||is_generated *]
+puts {[get_lib_cells -filter is_buffer==1 *]}
 report_object_full_names [get_lib_cells -filter is_buffer==1 *]
-puts "get_lib_cells 2"
+puts {[get_lib_cells -filter is_inverter==0 *]}
 report_object_full_names [get_lib_cells -filter is_inverter==0 *]
-puts "get_lib_pins"
+puts {[get_lib_pins -filter direction==input BUFx2_ASAP7_75t_R/*]}
 report_object_full_names [get_lib_pins -filter direction==input BUFx2_ASAP7_75t_R/*]
-puts "get_lib_pins 2"
+puts {[get_lib_pins -filter direction==output BUFx2_ASAP7_75t_R/*]}
 report_object_full_names [get_lib_pins -filter direction==output BUFx2_ASAP7_75t_R/*]
-puts "get_libs"
+puts {[get_libs -filter name==asap7_small *]}
 report_object_full_names [get_libs -filter name==asap7_small *]
-puts "get_nets"
+puts {[get_nets -filter name=~*q *]}
 report_object_full_names [get_nets -filter name=~*q *]
-puts "get_pins"
+puts {[get_pins -filter direction==input *]}
 report_object_full_names [get_pins -filter direction==input *]
-puts "get_pins 2"
+puts {[get_pins -filter direction==output *]}
 report_object_full_names [get_pins -filter direction==output *]
-puts "get_ports"
+puts {[get_ports -filter direction==input *]}
 report_object_full_names [get_ports -filter direction==input *]
-puts "get_ports 2"
+puts {[get_ports -filter direction==output *]}
 report_object_full_names [get_ports -filter direction==output *]