@fredo6

I reinstalled Fredo6_Tools to get a spin. Took it back out and relaunched without spin. This is the trace log from the previous session

LibFredo6Trace_26_1760445486517.txt

Another strange effect of note: in the log viewer window, when I export TXT, that worked and a popup opened asking if I want to open the file. I clicked YES, and SketchUp went into a spin! This seems the same as how the Plugin Store window hangs...

A skp file contains a human-readable (ASCII) header at the very beginning of the file, identifying the specific version of SketchUp used. However, the bulk of the file is a proprietary binary format. File recovery programs have a poor track record reconstructing binary files.

Try various offsets on the attached skp that contains a non-convex polygon. A couple of examples:

• edit the leading sign on the offset to get -20cm. A weird shape will be created.
• try just entering -1 (the model is in fractional inches). A self-intersecting set of edges will be created.

A general offset algorithm needs traps for special cases such as these, which add to the complexity. In the past, the built-in Offset Tool would also glitch on shapes such as this. I don't remember exactly which version fixed it (maybe SU 2019 or 2020?).

difficult_offset.skp