I was mainly responding to: > The biggest limitation is no fillets or bevels, but it sounds like FreeCAD can't do that either. which is simply untrue: FreeCAD

I was mainly responding to: > The biggest limitation is no fillets or bevels, but it sounds like FreeCAD can't do that either. which is simply untrue: FreeCAD can do fillets and chamfers. It has a built-in tool for them. It almost always works flawlessly. You're right that FreeCAD will occasionally segfault on a complicated chamfer, but generally this is foreshadowed by a gut feeling that the geometry is so complicated that you yourself actually don't know what a correct chamfer would even look like. But OK, FWIW, I just attempted the same Model Mania 2001 challenge in FreeCAD, and I got this: https://img.incoherency.co.uk/4072 https://img.incoherency.co.uk/4072 - it took me about 20 minutes. I had to guess the thickness of the central web as it doesn't appear to be shown on the drawing: https://blogs.solidworks.com/tech/wp-content/uploads/sites/4/Model-Mania-2001-Phase-1.jpg https://blogs.solidworks.com/tech/wp-content/uploads/sites/4... I didn't run into any issues or crashes with the fillets, the only thing that is arguably an issue is that FreeCAD makes the fillet that intersects with the front edge differently to how other tools do it. The one at the corner of the bottom of the large arc, where it touches the base plate. Arguably this is a FreeCAD bug, but it's hardly the end of the world. To say that FreeCAD "can't do" fillets is just wrong.