Imported rigidbody falls thrugh plane?

Hi, im testing scales between Cheetah 3D and Unity, so I can make a character, and so I made a simple cube, imported it in unity, made it have colliers, and put it in the scene. the colliders work, because if the FPS controller walks into the cube, it dosent go thrugh. But if I add a rigidbody component to it, it simply falls thrugh the plane. Why? And what should I do?

Are you using mesh colliders or primitive colliders?

Mesh colliders, as default. Should I change that to a box collider? Because the whole point of C3D is to make characters and animations, I dont want the characters to fall off the map, you know?

I believe that you can either check the “is kinematic” or the “use gravity” option to prevent your rigidbody from falling through. You can also use primitive colliders on each of the components of your object if you don’t want to use a single box collider.

When you attach the rigidbody, the object starts to be affected by gravity. A MeshCollider can’t collide with another MeshCollider unless one of them is marked as convex. Otherwise, they pass through each other. In this case, you could use a BoxCollider on your cube, and everything should work OK.

You might also get the effect you want if you use a kinematic rigidbody or switch gravity off, as Brad suggested. However, kinematic rigidbodies aren’t affected by normal forces and collisions, and you can imagine what might happen if gravity is switched off - proceed with caution!