UE doesn't wants to use imported custom collision on static mesh


I made a portal 3D model and imported 21 custom collision objects (UCX_MeshName_XX). The imported collision looks good in the preview window:

However, the hole does not work. If I shoot projectiles at the object, they simply collide with the hole and bounce off.
Did I made anything wrong? Why are my objects not flying through the hole although there is no collision object in it? It works with complex collision.

Thank you,


Found it. I had to uncheck “One Convex Hull per UCX”. However, I dont know why. What is the difference between “one convex hull per UCX_…” and “multiple (convex) hulls”?