Why do objects pass through a mesh/

I have a character with arms made from a cube object that use box colliders and low poly mountains that have a mesh collider. But when the arms run into the mountains, they go straight through instead of being deflected. The mountain has a mesh collider, not convex, and each arm has a box collider and a rigidbody, no gravity and non kinematic. Can someone please explain why the box colliders dont collide with the mesh collider?

Do you mean that the arms go through the mountain? Then it’s a clipping problem. You could fix it like this:

Make A Hands Layer and set it to the hands, then you should make another camera that only renders the “Hands” Layer and make it a child of your main camera. Make sure to set the new camera to “Depth only” and make the depth 2 and set your original camera’s depth to 1 and set it to not render the “Hands” layer.

if you have any questions or you didn’t understand my answer, just ask!
C:
@pearsonfrank001

Check physics settings to make sure mountain and box’s layers can collide with each-other.