,physics inside geometry with inward-pointing normals

I’m trying to make something that allows a player to control a physics-based object inside a “hollow” geometry object. I created my geometry object (basically a cylindrical room–but could be more complex), and flipped the normals so they all point inward. Then I place my player object inside the “room” object and fly it around. The player object is a mesh collider (marked convex) with a rigidbody which is moved by applying forces and torques. The room geometry is another mesh collider object (marked convex, I think), but with no rigidbody.

What happens is that the player object sometimes collides with the room geom, but sometimes passes right through. It seems this is due to the well-known problem with fast moving objects as it seems to depend on speed–but I’m not certain. I’ve tried fixing this by setting the collisions to be dynamic, continuous, etc, but nothing seems to make a difference.

What I’d like to know is: am I on the right track? Is this method doomed to failure? I’ve heard of non-collision problems being solved by making the geometry “thick”, but that wouldn’t work with my inverted geometry scheme.

Making the “room” mesh collider convex doesn’t make much sense. Do you know what convex means? It will create a solid collider that can’t have holes or surface-angles smaller then 180°. Leave the room MeshCollider as normal collider and you’d better use primitive colliders for your player object if possible.

Here’s a description of the convex hull.