Hello, I am unable to use the vellum grains in anny useful way since 90% of my grains just dont selfcolide.

Vellumbrush seems to work in some cases but also not after merging and unpacking setup
.

I cant figure out what the problem is. I'm quite sure the setup should work.

your Timescale is 1000
so you'd need much more substeps than 12 if that's on purpose

otherwise just set it to 1 and go from there

actually one more thing, since I was just testing with your merge bypassed as that was not colliding either with such high timescale

but

if you are merging with shapematched pieces, they by default don't collide within piece
and merging with the pile that doesn't have i@piece attribute would initialize them to 0 so the pile also wouldn't self collide nor collide with merged piece 0

to avoid this, set i@piece = -1; on your pile particles before packing and merging with pierces

Thank you for your time.
It is greatly appreciated.