How to prevent colliders from passing through each other?

Question

I am having trouble keeping game objects inside of a contained space. When they reach the edge, there is some momentary push back but then they will go right through the wal

Answer 1

How about set the Collision Detection of rigidbody to Continuous or Continuous Dynamic?

http://unity3d.com/support/documentation/Components/class-Rigidbody.html

Answer 2

Try setting the models to environment and static. That fix my issue.