In your case pre-rendering the basic shape should solve your problem. In some cases for speed reasons you may have to save some rendered modules as .stl's and then import them to continue the work. If the saved stl's are well formed you may still execute boolean operarations with them, however sometimes is not possible. jpmendes -- View this message in context: http://forum.openscad.org/reusing-unions-objects-tp16464p16470.html Sent from the OpenSCAD mailing list archive at Nabble.com.