diff --git a/scad/Makefile b/scad/Makefile
index 90dfe7c..b57ae61 100644
--- a/scad/Makefile
+++ b/scad/Makefile
@@ -2,7 +2,8 @@
 PREFIX=intval2
 
 OPENSCAD=openscad
-OPENSCAD_OPTIONS=-D VERBOSE=false
+OPENSCAD_OPTIONS_STL=--enable sort-stl -D VERBOSE=false
+OPENSCAD_OPTIONS_DXF=-D VERBOSE=false
 
 STL=../stl
 DXF=../dxf
@@ -25,7 +26,7 @@ cleanall:
 # Dependencies for models
 
 $(MODELS) : $(STL)/$(PREFIX)_%.stl : $(PREFIX).scad
-	$(OPENSCAD) $(OPENSCAD_OPTIONS) -o $@ -D PART=\"$(subst $(PREFIX)_,,$(subst .stl,,$(@F)))\" $<
+	$(OPENSCAD) $(OPENSCAD_OPTIONS_STL) -o $@ -D PART=\"$(subst $(PREFIX)_,,$(subst .stl,,$(@F)))\" $<
 
 $(LASER) : $(DXF)/$(PREFIX)_%.dxf : $(PREFIX).scad
-	$(OPENSCAD) $(OPENSCAD_OPTIONS) -o $@ -D PART=\"$(subst $(PREFIX)_,,$(subst .dxf,,$(@F)))\" $<
\ No newline at end of file
+	$(OPENSCAD) $(OPENSCAD_OPTIONS_DXF) -o $@ -D PART=\"$(subst $(PREFIX)_,,$(subst .dxf,,$(@F)))\" $<
\ No newline at end of file