I edited the scorpion model and I think it needs a new collision, because it always says in sapien it does not match the collision and won't be collidable.

How would I go by creating a new one, and what would I need to do?

Before exporting, fix all open edges, then export.

Use "tool collision-geometry folder\folder

It should work now.

You could make it by optomizing the gbxmodel, but keep the corners and edges. You want the collision model to be simple, but accurate. Texturing is ignored, but it must follow the sealed world rules. Meaning the different parts of the tank shouldn't overlap.

It can overlap, it just can not have faces in the same exact position and location.

Thanks!