SolidWorks vs Inventor vs FreeCAD Fillet Failures — Why Blends Fail and How Each Kernel Handles It
You click “Fillet,” pick an edge, type a radius, and hit the green check. The edge rounds off. Done. Until it isn’t. Until you get “Fillet operation failed” on a perfectly reasonable-looking edge. Or until the same 2mm radius works on one edge but blows up on the adjacent one. Or until your model rebuilds fine in SolidWorks but the same STEP file fillets differently in Inventor. These aren’t random bugs. They’re the predictable result of three completely different geometric kernels making three completely different decisions about how to roll a ball along an edge. We decompiled the DLLs, read the exported symbols, and walked through the open-source code to see what’s actually happening. ...