tp3 wrote > Degenerate faces are usually not a problem for slicing, OpenSCAD > would have trouble re-importing those file as it currently does > not handle faces with zero area well. I have imported the STL files that had the degenerated faces issue back into scad without repairing them first (I had no idea they were broken) and unioned, differenced, etc without any problems. It turns out that the stl for the finished products turned out to be broken and needed repair too. When I went back and checked the individual stl files I found out they were all broken. tp3 wrote > FWIW, I never needed to repair the models I've created in OpenSCAD, > so "many need repair" is probably a bit exaggerated. Due to the > issue mentioned above it might occur more often for models with > very tiny details which I don't create as that would not print > anyway. I never viewed an stl file before outside of OpenSCAD since I never intended to print anything (I don't have a printer or access to one). My windows 10 upgrade came with 3D Builder so I started looked at my stl exports for the first time about a month ago using it. As I tried to play around with them many needed repairing before the software would let me do anything. I was toying with using Microsoft's service to get something I modeled printed for the first time. Thank you for helping. -- View this message in context: http://forum.openscad.org/STL-Exports-Many-need-repair-and-I-can-t-tell-why-tp16463p16490.html Sent from the OpenSCAD mailing list archive at Nabble.com.