Hi @NFinET,
Thanks for your well written query, appreciate the effort.
Erase functionality currently does not support erasure of any collision data. Erasure was added in a recent release in response to a user request for simple paint erase functionality.
However, this functionality should be reasonably easy to build out with some minor code additions. I’m not sure when the next engine release is, but if possible I’d like to wait until that point to add this functionality.
If you need it sooner and are comfortable with coding you may be able to inspect the logic in UDonMeshPainterComponent::SetupPaintingPrerequisites and simply add some logic which checks whether Stroke.bEraseMode is true and if so, remove the stroke instead of registering it.
If you need help with implementing that on your own for now, do let me know!