I’ve created this below in blender, and opened it in Unity. When I add a mesh collider, it is closed at the top. It only happens when I click convex. My “skater” is also a mesh collider so my understanding is that they both need to be convex.

Is there anyway to remove the top of the mesh collider?

The Convex option creates a convex hull out of the given geometry. The half pipe should be either non-convex, or you should split it into convex meshes in Blender. You can preview the effect of the Convex option in Blender by selecting your geometry, then hit Space and selecting “Convex Hull”.

I’d recommend you to use non-convex colliders for the scenery and static parts, then build your characters, avatars, etc using several convex colliders combined.

A similar example: I develop vehicle demos. The sceneries are built using non-convex colliders. Each vehicle has two or more convex colliders combined for resembling the vehicle’s non-convex shape.