I have been trying to do Rigid body physics tutorials, and I keep running into the same issue. To show my problem, I did a basic cube with a basic sphere.I delete the top face of the cube. I add Active Rigid Body on the sphere, and Passive Rigid Body on the empty box. However, when I hit play to run the animation, the sphere interacts with an invisible wall, stopping the sphere from hitting the bottom of the box, and I have tried this on other shapes, and I'm still getting this problem. I encounter this same problem if I try to extrude the edges of a plane, acting as if a barrier is still there.