I cannot reproduce a crash. List the steps exactly. I selected Pocket006 Face5, created a sketch, added a rectangle, pocketed the sketch. By the way, attaching to a face is a bad idea due to TNP , but this is an unrelated bug. TNP will not generally cause a crash, just a broken model if changes are ...

You could try surface modeling. Connect the sketch edges, and then use the surface tools in Surface workbench to get the faces. Once you have all the faces use the Solid (green cube icon) tool in Curves to create the solid.

The blue checkmark is the indicator an object needs to be recomputed.

Give the Macro_Parametric_Defeaturing macro a go, too. Defeaturing works by selecting the faces, not the edges or vertices, so make sure that's what you are selecting. It can also fail where the original object has defects that prevent boolean operations from working, so use Part workbench Check Geo...

Just be aware as far as I know you cannot open a file saved with LinkStage version in standard FreeCAD.

That's just how I did it. I could have converted existing bsplines to construction mode and added the new ones in that same sketch. All the constraints make it kind of messy, so I opted for this approach instead. You're correct that external geometry can lead to TNP . It's better to use elements fro...

I created a new sketch, then created links to external geometry for the 5 edges in the other sketch. I used the bspline by knots tool to add the 2 new bsplines, just picking random points along the external edges. It's not super precise to the original, but by the looks of it, probably good enough. ...

I remade the sketch. I didn't check validate sketch.

Works fine here. I used Through All for the type and symmetric to plane. Snip macro screenshot-e04e96.png OS: Windows 10 build 19045 Word size of FreeCAD: 64-bit Version: 0.22.0dev.35249 (Git) Build type: Release Branch: main Hash: 94ca51b7799b2ac60a2a56d7e6e753bb97a73671 Python 3.10.13, Qt 5.15.8, ...

Thanks, Ed. I had caught that typo and fixed it in my local copy, but forgot to update the code in the post.