I have a vehicle where the wheels fall through the floor. The wheel static meshes are in the robot collision group and the floor surface is in the obstacle group. The floor is set to block robot, and the wheel is set to block obstacle. However, when I start the game the wheels immediately fall through the floor.
As you can see the wheels are part way though the ground, and the body is resting on the floor. The body is set to the component collision group and will ignore all collision groups, BUT IT DOES NOT FALL THROUGH THE FLOOR. The body and wheels are set to query only (with no physics) and the floor is set to collision enabled (query and physics).
Why are the wheels displaying this behavior?