Collision issues with blueprints but not Static meshes

Im having problems with my static meshes,
I am using one with cube collison set from the static mesh editor.
The other is using complex as simple.

If i use them both as static meshes they collide proper (in this case, one is static and one is simulating physics)

If the static one is a blueprint with the root at the static mesh, even on block all my dynamic (simulated physics) static mesh set to block all will fall through it.

My player capsule sits happily on my blueprint static mesh collision. My FPS Projectiles bounce off them fine.
They do not collide with each other when set to block all however.

Any ideas? Is this clear or shall i provide pictures? Thank you! Very noobie question im new to level design!

For discussion purposes, I’m going to refer to your mesh with the cube collision as “Cube” and your complex mesh as “Ball.”

So here’s what might be the problem; in blueprint, the default collision settings are not always what you want. The two things you need to focus on are “what body channel do I want this mesh to be seen as (e.g. PhysicsBody, StaticBody, Vehicle)” and “what bodies should it block, overlap, or ignore.” You probably have the body of “Cube” set to something that “Ball” ignores or overlaps with, and/or you may have the body of “Ball” set to something that isn’t on the block list for BlockAllDynamic.

For testing purposes, look in the “Default” tab in the blueprint editor for your static meshes; then, set both meshes to block all. If that works fine, then at that point you can selectively change the collison set using custom to block/overlap what you want and or just change the body type accordingly.

If that doesn’t work, try setting the root to “scene component” (basically just empty air that’s commonly used as a root dummy) and then add your mesh under it (think player capsule and mesh heirarchy). Then repeat the above.

Hope this helps,

Thanks ,
I ended up experimenting and found that when i used complex collision as simple, then had my mesh set to movable it caused problems. Setting it to static seemed to fix my problems, but i don’t fully understand what’s going on there in the backend and why.