The last time I encountered this annoying bug was in version 2018, but now it has started to appear in version 2021 and is not easy to recover from. How can I thoroughly solve this problem?
This was usually suspected to relate to a couple of specific extensions.
If you list yours and we may be able to suggest one that could be faulty.
None of those are jumping out at me.
FAK is a bit flaky from memory, you have Upright Extruder so maybe you don’t need it.
I don’t know Fence-Maker.
Do you have autosave on and does it appear to happen when autosave kicks in?
From memory, the best it was tracked down to was a plugin conflict with autosave. Personally I don’t use autosave as it usually kicks in just at the wrong time and I prefer to manually save.
okay, thank you~!
I’ll remove FAK and try again. I haven’t noticed any issues during the auto-save period for now. The auto-save function is enabled because I’m afraid the file might crash without saving.
Also save your file manually (for instance daly) as _ filename_date.skp.
Even with autosave you’re not 100% sure you won’t lose your file.
I have seen a similar result (long spurious triangles stretching to the world origin added by SketchUp) caused by Undo after a Check Validity operation that had changed (in my opinion damaged) the model’s geometry. This has happened to me a number of times with SketchUp Pro 2018. Often if I Undo a few more steps those triangles will be removed.