diff --git a/testdata/scad/misc/empty-union.scad b/testdata/scad/misc/empty-union.scad
new file mode 100644
index 00000000..f16a9d46
--- /dev/null
+++ b/testdata/scad/misc/empty-union.scad
@@ -0,0 +1,4 @@
+union() {
+  polyhedron();
+  polyhedron();
+}
diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index 4e455db5..cdec9751 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -951,6 +951,52 @@ function(add_cmdline_test TESTCMD_BASENAME)
   endforeach()
 endfunction()
 
+#
+# Usage add_failing_test(testbasename RETVAL <expected return value>
+#                        [EXE <executable>] [SCRIPT <script>] [ARGS <args to exe>]
+#                        FILES <test files>)
+#
+function(add_failing_test TESTCMD_BASENAME)
+  cmake_parse_arguments(TESTCMD "" "RETVAL;EXE;SCRIPT;" "FILES;ARGS" ${ARGN})
+
+  if (TESTCMD_EXE)
+    set(TESTNAME_OPTION -t ${TESTCMD_BASENAME})
+  else()
+    # If no executable was specified, assume it was built by us and resides here
+    set(TESTCMD_EXE ${CMAKE_BINARY_DIR}/${TESTCMD_BASENAME})
+  endif()
+
+  # Add tests from args
+  foreach (SCADFILE ${TESTCMD_FILES})
+    get_filename_component(FILE_BASENAME ${SCADFILE} NAME_WE)
+    string(REPLACE " " "_" FILE_BASENAME ${FILE_BASENAME}) # Test names cannot include spaces
+    set(TEST_FULLNAME "${TESTCMD_BASENAME}_${FILE_BASENAME}")
+    list(FIND DISABLED_TESTS ${TEST_FULLNAME} DISABLED)
+
+    if (${DISABLED} EQUAL -1)
+      # Handle configurations
+      unset(FOUNDCONFIGS)
+      get_test_config(${TEST_FULLNAME} FOUNDCONFIGS)
+      if (NOT FOUNDCONFIGS)
+        set_test_config(Default ${TEST_FULLNAME})
+      endif()
+      set_test_config(All ${TEST_FULLNAME})
+      unset(FOUNDCONFIGS)
+      get_test_config(${TEST_FULLNAME} FOUNDCONFIGS)
+      set(CONFARG CONFIGURATIONS)
+      set(CONFVAL ${FOUNDCONFIGS})
+
+      # The python script cannot extract the testname when given extra parameters
+      if (TESTCMD_ARGS)
+        set(FILENAME_OPTION -f ${FILE_BASENAME})
+      endif()
+
+      add_test(NAME ${TEST_FULLNAME} ${CONFARG} ${CONFVAL} COMMAND ${TESTCMD_EXE} ${TESTCMD_SCRIPT} "${SCADFILE}" ${TESTCMD_ARGS})
+      set_property(TEST ${TEST_FULLNAME} PROPERTY ENVIRONMENT "${CTEST_ENVIRONMENT}")
+    endif()
+  endforeach()
+endfunction()
+
 enable_testing()
 
 
@@ -973,7 +1019,12 @@ file(GLOB FEATURES_2D_FILES ${CMAKE_SOURCE_DIR}/../testdata/scad/2D/features/*.s
 file(GLOB DEPRECATED_3D_FILES ${CMAKE_SOURCE_DIR}/../testdata/scad/3D/deprecated/*.scad)
 file(GLOB SCAD_DXF_FILES ${CMAKE_SOURCE_DIR}/../testdata/scad/dxf/*.scad)
 file(GLOB FUNCTION_FILES ${CMAKE_SOURCE_DIR}/../testdata/scad/functions/*.scad)
-file(GLOB EXAMPLE_FILES ${CMAKE_SOURCE_DIR}/../examples/*/*.scad)
+file(GLOB_RECURSE EXAMPLE_3D_FILES ${CMAKE_SOURCE_DIR}/../examples/*.scad)
+
+list(REMOVE_ITEM EXAMPLE_3D_FILES ${CMAKE_SOURCE_DIR}/../examples/Shapes/flat_body.scad)
+list(APPEND EXAMPLE_2D_FILES ${CMAKE_SOURCE_DIR}/../examples/Shapes/flat_body.scad)
+
+list(APPEND EXAMPLE_FILES ${EXAMPLE_3D_FILES} ${EXAMPLE_2D_FILES})
 
 list(APPEND ECHO_FILES ${FUNCTION_FILES}
             ${CMAKE_SOURCE_DIR}/../testdata/scad/3D/features/for-tests.scad
@@ -1016,8 +1067,8 @@ list(APPEND DUMPTEST_FILES ${CMAKE_SOURCE_DIR}/../testdata/scad/misc/escape-test
                            ${CMAKE_SOURCE_DIR}/../testdata/scad/misc/allfunctions.scad
                            ${CMAKE_SOURCE_DIR}/../testdata/scad/misc/allmodules.scad)
 
-list(APPEND CGALPNGTEST_2D_FILES ${FEATURES_2D_FILES} ${SCAD_DXF_FILES})
-list(APPEND CGALPNGTEST_3D_FILES ${FEATURES_3D_FILES} ${DEPRECATED_3D_FILES} ${EXAMPLE_FILES})
+list(APPEND CGALPNGTEST_2D_FILES ${FEATURES_2D_FILES} ${SCAD_DXF_FILES} ${EXAMPLE_2D_FILES})
+list(APPEND CGALPNGTEST_3D_FILES ${FEATURES_3D_FILES} ${DEPRECATED_3D_FILES} ${EXAMPLE_3D_FILES})
 list(APPEND CGALPNGTEST_3D_FILES ${CMAKE_SOURCE_DIR}/../testdata/scad/misc/include-tests.scad
                            ${CMAKE_SOURCE_DIR}/../testdata/scad/misc/use-tests.scad
                            ${CMAKE_SOURCE_DIR}/../testdata/scad/bugs/transform-nan-inf-tests.scad
@@ -1025,7 +1076,8 @@ list(APPEND CGALPNGTEST_3D_FILES ${CMAKE_SOURCE_DIR}/../testdata/scad/misc/inclu
                            ${CMAKE_SOURCE_DIR}/../testdata/scad/misc/localfiles_dir/localfiles-compatibility-test.scad
                            ${CMAKE_SOURCE_DIR}/../testdata/scad/misc/rotate-empty-bbox.scad
                            ${CMAKE_SOURCE_DIR}/../testdata/scad/misc/empty-shape-tests.scad
-                           ${CMAKE_SOURCE_DIR}/../testdata/scad/misc/null-polygons.scad)
+                           ${CMAKE_SOURCE_DIR}/../testdata/scad/misc/null-polygons.scad
+                           ${CMAKE_SOURCE_DIR}/../testdata/scad/misc/empty-union.scad)
 
 list(APPEND CGALPNGTEST_FILES ${CGALPNGTEST_2D_FILES} ${CGALPNGTEST_3D_FILES})
 list(APPEND OPENCSGTEST_FILES ${CGALPNGTEST_FILES})
@@ -1036,16 +1088,17 @@ list(APPEND CGALSTLSANITYTEST_FILES ${CMAKE_SOURCE_DIR}/../testdata/scad/misc/no
 
 file(GLOB EXPERIMENTAL_TEXT_FILES ${CMAKE_SOURCE_DIR}/../testdata/scad/experimental/text-*.scad)
 
-list(APPEND EXPORT3D_TEST_FILES ${EXAMPLE_FILES})
-list(APPEND EXPORT3D_TEST_FILES ${CMAKE_SOURCE_DIR}/../testdata/scad/3D/features/polyhedron-nonplanar-tests.scad)
+list(APPEND EXPORT3D_TEST_FILES ${EXAMPLE_3D_FILES})
+list(APPEND EXPORT3D_TEST_FILES ${CMAKE_SOURCE_DIR}/../testdata/scad/3D/features/polyhedron-nonplanar-tests.scad
+                                ${CMAKE_SOURCE_DIR}/../testdata/scad/3D/features/polyhedron-tests.scad
+                                ${CMAKE_SOURCE_DIR}/../testdata/scad/3D/features/rotate_extrude-tests.scad
+                                ${CMAKE_SOURCE_DIR}/../testdata/scad/3D/features/union-coincident-test.scad
+                                ${CMAKE_SOURCE_DIR}/../testdata/scad/misc/null-polygons.scad)
+
 disable_tests(
   # This doesn't output anything
   dxfpngtest_nothing-decimal-comma-separated
 
-  # the flat_body is not 3d so dont do 3d-tests on it
-  stlpngtest_flat_body
-  offpngtest_flat_body
-
   # these take too long, for little relative gain in testing
   stlpngtest_iteration
   offpngtest_iteration
@@ -1056,7 +1109,7 @@ disable_tests(
 )
 
 # 2D tests
-list(APPEND ALL_2D_FILES ${FEATURES_2D_FILES} ${SCAD_DXF_FILES} ${EXPERIMENTAL_TEXT_FILES})
+list(APPEND ALL_2D_FILES ${FEATURES_2D_FILES} ${SCAD_DXF_FILES} ${EXAMPLE_2D_FILES} ${EXPERIMENTAL_TEXT_FILES})
 
 # FIXME: This test illustrates a weakness in child() combined with modifiers.
 # Reenable it when this is improved
@@ -1161,6 +1214,8 @@ foreach(FILE ${EXAMPLE_FILES})
   set_test_config(Examples ${TEST_FULLNAME})
   get_test_fullname(csgpngtest ${FILE} TEST_FULLNAME)
   set_test_config(Examples ${TEST_FULLNAME})
+  get_test_fullname(monotonepngtest ${FILE} TEST_FULLNAME)
+  set_test_config(Examples ${TEST_FULLNAME})
   get_test_fullname(stlpngtest ${FILE} TEST_FULLNAME)
   set_test_config(Examples ${TEST_FULLNAME})
   get_test_fullname(offpngtest ${FILE} TEST_FULLNAME)
@@ -1235,13 +1290,30 @@ add_cmdline_test(throwntogethertest EXE ${OPENSCAD_BINPATH} ARGS --preview=throw
 # with anything. It's self-contained and returns != 0 on error
 add_cmdline_test(cgalstlsanitytest EXE ${CMAKE_SOURCE_DIR}/cgalstlsanitytest SUFFIX txt ARGS ${OPENSCAD_BINPATH} FILES ${CGALSTLSANITYTEST_FILES})
 
+#
 # Export/Import tests
-add_cmdline_test(stlpngtest EXE ${PYTHON_EXECUTABLE} SCRIPT ${CMAKE_SOURCE_DIR}/export_import_pngtest.py ARGS --openscad=${OPENSCAD_BINPATH} --format=STL SUFFIX png FILES ${EXPORT3D_TEST_FILES})
-add_cmdline_test(offpngtest EXE ${PYTHON_EXECUTABLE} SCRIPT ${CMAKE_SOURCE_DIR}/export_import_pngtest.py ARGS --openscad=${OPENSCAD_BINPATH} --format=OFF EXPECTEDDIR stlpngtest SUFFIX png FILES ${EXPORT3D_TEST_FILES})
+#
+
+# Issue #337
+set_test_config(Bugs stlpngtest_polyhedron-tests)
+# Issue #910
+set_test_config(Bugs offpngtest_polyhedron-tests)
+
+add_cmdline_test(monotonepngtest EXE ${OPENSCAD_BINPATH} ARGS --colorscheme=Monotone --enable=text --render -o SUFFIX png FILES ${EXPORT3D_TEST_FILES})
+add_cmdline_test(stlpngtest EXE ${PYTHON_EXECUTABLE} SCRIPT ${CMAKE_SOURCE_DIR}/export_import_pngtest.py ARGS --openscad=${OPENSCAD_BINPATH} --format=STL EXPECTEDDIR monotonepngtest SUFFIX png FILES ${EXPORT3D_TEST_FILES})
+add_cmdline_test(offpngtest EXE ${PYTHON_EXECUTABLE} SCRIPT ${CMAKE_SOURCE_DIR}/export_import_pngtest.py ARGS --openscad=${OPENSCAD_BINPATH} --format=OFF EXPECTEDDIR monotonepngtest SUFFIX png FILES ${EXPORT3D_TEST_FILES})
 add_cmdline_test(dxfpngtest EXE ${PYTHON_EXECUTABLE} SCRIPT ${CMAKE_SOURCE_DIR}/export_import_pngtest.py ARGS --openscad=${OPENSCAD_BINPATH} --format=DXF EXPECTEDDIR cgalpngtest SUFFIX png FILES ${ALL_2D_FILES})
 
-# Add experimental tests
 
+#
+# Failing tests
+#
+add_failing_test(stlfailedtest EXE ${PYTHON_EXECUTABLE} SCRIPT ${CMAKE_SOURCE_DIR}/shouldfail.py ARGS --openscad=${OPENSCAD_BINPATH} --retval=1 -o SUFFIX stl FILES ${CMAKE_SOURCE_DIR}/../testdata/scad/misc/empty-union.scad)
+add_failing_test(offfailedtest EXE ${PYTHON_EXECUTABLE} SCRIPT ${CMAKE_SOURCE_DIR}/shouldfail.py ARGS --openscad=${OPENSCAD_BINPATH} --retval=1 -o SUFFIX off FILES ${CMAKE_SOURCE_DIR}/../testdata/scad/misc/empty-union.scad)
+
+#
+# Add experimental tests
+#
 add_cmdline_test(dumptest EXE ${OPENSCAD_BINPATH} ARGS --enable=text -o SUFFIX csg FILES ${EXPERIMENTAL_TEXT_FILES})
 add_cmdline_test(cgalpngtest EXE ${OPENSCAD_BINPATH} ARGS --render --enable=text -o SUFFIX png FILES ${EXPERIMENTAL_TEXT_FILES})
 add_cmdline_test(opencsgtest EXE ${OPENSCAD_BINPATH} ARGS --enable=text -o SUFFIX png FILES ${EXPERIMENTAL_TEXT_FILES})
diff --git a/tests/regression/cgalpngtest/empty-union-expected.png b/tests/regression/cgalpngtest/empty-union-expected.png
new file mode 100644
index 00000000..08ee92b2
Binary files /dev/null and b/tests/regression/cgalpngtest/empty-union-expected.png differ
diff --git a/tests/regression/stlpngtest/advance_intersection-expected.png b/tests/regression/monotonepngtest/advance_intersection-expected.png
similarity index 100%
rename from tests/regression/stlpngtest/advance_intersection-expected.png
rename to tests/regression/monotonepngtest/advance_intersection-expected.png
diff --git a/tests/regression/stlpngtest/chopped_blocks-expected.png b/tests/regression/monotonepngtest/chopped_blocks-expected.png
similarity index 100%
rename from tests/regression/stlpngtest/chopped_blocks-expected.png
rename to tests/regression/monotonepngtest/chopped_blocks-expected.png
diff --git a/tests/regression/stlpngtest/cut_view-expected.png b/tests/regression/monotonepngtest/cut_view-expected.png
similarity index 100%
rename from tests/regression/stlpngtest/cut_view-expected.png
rename to tests/regression/monotonepngtest/cut_view-expected.png
diff --git a/tests/regression/stlpngtest/demo_cut-expected.png b/tests/regression/monotonepngtest/demo_cut-expected.png
similarity index 100%
rename from tests/regression/stlpngtest/demo_cut-expected.png
rename to tests/regression/monotonepngtest/demo_cut-expected.png
diff --git a/tests/regression/stlpngtest/difference-expected.png b/tests/regression/monotonepngtest/difference-expected.png
similarity index 100%
rename from tests/regression/stlpngtest/difference-expected.png
rename to tests/regression/monotonepngtest/difference-expected.png
diff --git a/tests/regression/stlpngtest/difference_cube-expected.png b/tests/regression/monotonepngtest/difference_cube-expected.png
similarity index 100%
rename from tests/regression/stlpngtest/difference_cube-expected.png
rename to tests/regression/monotonepngtest/difference_cube-expected.png
diff --git a/tests/regression/stlpngtest/difference_sphere-expected.png b/tests/regression/monotonepngtest/difference_sphere-expected.png
similarity index 100%
rename from tests/regression/stlpngtest/difference_sphere-expected.png
rename to tests/regression/monotonepngtest/difference_sphere-expected.png
diff --git a/tests/regression/monotonepngtest/empty-union-expected.png b/tests/regression/monotonepngtest/empty-union-expected.png
new file mode 100644
index 00000000..08ee92b2
Binary files /dev/null and b/tests/regression/monotonepngtest/empty-union-expected.png differ
diff --git a/tests/regression/stlpngtest/fan_view-expected.png b/tests/regression/monotonepngtest/fan_view-expected.png
similarity index 100%
rename from tests/regression/stlpngtest/fan_view-expected.png
rename to tests/regression/monotonepngtest/fan_view-expected.png
diff --git a/tests/regression/stlpngtest/fence-expected.png b/tests/regression/monotonepngtest/fence-expected.png
similarity index 100%
rename from tests/regression/stlpngtest/fence-expected.png
rename to tests/regression/monotonepngtest/fence-expected.png
diff --git a/tests/regression/monotonepngtest/fractal-expected.png b/tests/regression/monotonepngtest/fractal-expected.png
new file mode 100644
index 00000000..f9d0246a
Binary files /dev/null and b/tests/regression/monotonepngtest/fractal-expected.png differ
diff --git a/tests/regression/stlpngtest/intersecting-expected.png b/tests/regression/monotonepngtest/intersecting-expected.png
similarity index 100%
rename from tests/regression/stlpngtest/intersecting-expected.png
rename to tests/regression/monotonepngtest/intersecting-expected.png
diff --git a/tests/regression/stlpngtest/intersection-expected.png b/tests/regression/monotonepngtest/intersection-expected.png
similarity index 100%
rename from tests/regression/stlpngtest/intersection-expected.png
rename to tests/regression/monotonepngtest/intersection-expected.png
diff --git a/tests/regression/stlpngtest/iteration-expected.png b/tests/regression/monotonepngtest/iteration-expected.png
similarity index 100%
rename from tests/regression/stlpngtest/iteration-expected.png
rename to tests/regression/monotonepngtest/iteration-expected.png
diff --git a/tests/regression/stlpngtest/logo_and_text-expected.png b/tests/regression/monotonepngtest/logo_and_text-expected.png
similarity index 100%
rename from tests/regression/stlpngtest/logo_and_text-expected.png
rename to tests/regression/monotonepngtest/logo_and_text-expected.png
diff --git a/tests/regression/monotonepngtest/null-polygons-expected.png b/tests/regression/monotonepngtest/null-polygons-expected.png
new file mode 100644
index 00000000..2621c673
Binary files /dev/null and b/tests/regression/monotonepngtest/null-polygons-expected.png differ
diff --git a/tests/regression/stlpngtest/offset-expected.png b/tests/regression/monotonepngtest/offset-expected.png
similarity index 100%
rename from tests/regression/stlpngtest/offset-expected.png
rename to tests/regression/monotonepngtest/offset-expected.png
diff --git a/tests/regression/stlpngtest/polyhedron-expected.png b/tests/regression/monotonepngtest/polyhedron-expected.png
similarity index 100%
rename from tests/regression/stlpngtest/polyhedron-expected.png
rename to tests/regression/monotonepngtest/polyhedron-expected.png
diff --git a/tests/regression/stlpngtest/polyhedron-nonplanar-tests-expected.png b/tests/regression/monotonepngtest/polyhedron-nonplanar-tests-expected.png
similarity index 100%
rename from tests/regression/stlpngtest/polyhedron-nonplanar-tests-expected.png
rename to tests/regression/monotonepngtest/polyhedron-nonplanar-tests-expected.png
diff --git a/tests/regression/monotonepngtest/polyhedron-tests-expected.png b/tests/regression/monotonepngtest/polyhedron-tests-expected.png
new file mode 100644
index 00000000..78f524c0
Binary files /dev/null and b/tests/regression/monotonepngtest/polyhedron-tests-expected.png differ
diff --git a/tests/regression/monotonepngtest/rotate_extrude-tests-expected.png b/tests/regression/monotonepngtest/rotate_extrude-tests-expected.png
new file mode 100644
index 00000000..5718bdac
Binary files /dev/null and b/tests/regression/monotonepngtest/rotate_extrude-tests-expected.png differ
diff --git a/tests/regression/stlpngtest/rounded_box-expected.png b/tests/regression/monotonepngtest/rounded_box-expected.png
similarity index 100%
rename from tests/regression/stlpngtest/rounded_box-expected.png
rename to tests/regression/monotonepngtest/rounded_box-expected.png
diff --git a/tests/regression/stlpngtest/search-expected.png b/tests/regression/monotonepngtest/search-expected.png
similarity index 100%
rename from tests/regression/stlpngtest/search-expected.png
rename to tests/regression/monotonepngtest/search-expected.png
diff --git a/tests/regression/stlpngtest/sphere-expected.png b/tests/regression/monotonepngtest/sphere-expected.png
similarity index 100%
rename from tests/regression/stlpngtest/sphere-expected.png
rename to tests/regression/monotonepngtest/sphere-expected.png
diff --git a/tests/regression/stlpngtest/surface-expected.png b/tests/regression/monotonepngtest/surface-expected.png
similarity index 100%
rename from tests/regression/stlpngtest/surface-expected.png
rename to tests/regression/monotonepngtest/surface-expected.png
diff --git a/tests/regression/stlpngtest/text-expected.png b/tests/regression/monotonepngtest/text-expected.png
similarity index 100%
rename from tests/regression/stlpngtest/text-expected.png
rename to tests/regression/monotonepngtest/text-expected.png
diff --git a/tests/regression/stlpngtest/text_on_cube-expected.png b/tests/regression/monotonepngtest/text_on_cube-expected.png
similarity index 100%
rename from tests/regression/stlpngtest/text_on_cube-expected.png
rename to tests/regression/monotonepngtest/text_on_cube-expected.png
diff --git a/tests/regression/stlpngtest/translate-expected.png b/tests/regression/monotonepngtest/translate-expected.png
similarity index 100%
rename from tests/regression/stlpngtest/translate-expected.png
rename to tests/regression/monotonepngtest/translate-expected.png
diff --git a/tests/regression/stlpngtest/translation-expected.png b/tests/regression/monotonepngtest/translation-expected.png
similarity index 100%
rename from tests/regression/stlpngtest/translation-expected.png
rename to tests/regression/monotonepngtest/translation-expected.png
diff --git a/tests/regression/stlpngtest/tripod-expected.png b/tests/regression/monotonepngtest/tripod-expected.png
similarity index 100%
rename from tests/regression/stlpngtest/tripod-expected.png
rename to tests/regression/monotonepngtest/tripod-expected.png
diff --git a/tests/regression/monotonepngtest/union-coincident-test-expected.png b/tests/regression/monotonepngtest/union-coincident-test-expected.png
new file mode 100644
index 00000000..00d8cb34
Binary files /dev/null and b/tests/regression/monotonepngtest/union-coincident-test-expected.png differ
diff --git a/tests/regression/stlpngtest/union-expected.png b/tests/regression/monotonepngtest/union-expected.png
similarity index 100%
rename from tests/regression/stlpngtest/union-expected.png
rename to tests/regression/monotonepngtest/union-expected.png
diff --git a/tests/regression/opencsgtest/empty-union-expected.png b/tests/regression/opencsgtest/empty-union-expected.png
new file mode 100644
index 00000000..08ee92b2
Binary files /dev/null and b/tests/regression/opencsgtest/empty-union-expected.png differ
diff --git a/tests/regression/stlpngtest/fractal-expected.png b/tests/regression/stlpngtest/fractal-expected.png
deleted file mode 100644
index e69de29b..00000000
diff --git a/tests/regression/throwntogethertest/empty-union-expected.png b/tests/regression/throwntogethertest/empty-union-expected.png
new file mode 100644
index 00000000..08ee92b2
Binary files /dev/null and b/tests/regression/throwntogethertest/empty-union-expected.png differ
diff --git a/tests/shouldfail.py b/tests/shouldfail.py
new file mode 100644
index 00000000..08ab8981
--- /dev/null
+++ b/tests/shouldfail.py
@@ -0,0 +1,56 @@
+#!/usr/bin/env python
+
+# Test expected failure
+#
+#
+# Usage: <script> <inputfile> --openscad=<executable-path> --retval=<retval> [openscad args]
+#
+#
+# This script should return 0 on success, not-0 on error.
+#
+
+import sys, os, re, subprocess, argparse
+
+def failquit(*args):
+	if len(args)!=0: print(args)
+	print('export_import_pngtest args:',str(sys.argv))
+	print('exiting export_import_pngtest.py with failure')
+	sys.exit(1)
+
+def createImport(inputfile, scadfile):
+        print ('createImport: ' + inputfile + " " + scadfile)
+        outputdir = os.path.dirname(scadfile)
+        try:
+                if outputdir and not os.path.exists(outputdir): os.mkdir(outputdir)
+                f = open(scadfile,'w')
+                f.write('import("'+inputfile+'");'+os.linesep)
+                f.close()
+        except:
+                failquit('failure while opening/writing ' + scadfile + ': ' + str(sys.exc_info()))
+        
+
+#
+# Parse arguments
+#
+parser = argparse.ArgumentParser()
+parser.add_argument('--openscad', required=True, help='Specify OpenSCAD executable')
+parser.add_argument('--retval', required=True, help='Expected return value')
+args,remaining_args = parser.parse_known_args()
+
+inputfile = remaining_args[0]         # Can be .scad file or a file to be imported
+remaining_args = remaining_args[1:]    # Passed on to the OpenSCAD executable
+
+if not os.path.exists(inputfile):
+	failquit('cant find input file named: ' + inputfile)
+if not os.path.exists(args.openscad):
+	failquit('cant find openscad executable named: ' + args.openscad)
+
+inputpath, inputfilename = os.path.split(inputfile)
+inputbasename,inputsuffix = os.path.splitext(inputfilename)
+
+export_cmd = [args.openscad, inputfile] + remaining_args
+print('Running OpenSCAD:')
+print(' '.join(export_cmd))
+result = subprocess.call(export_cmd)
+if str(result) != str(args.retval):
+	failquit('OpenSCAD failed with unexpected return value ' + str(result) + ' (should be ' + str(args.retval) + ')')