Rigidbodies Ignored

Unity Engine
1

I have two different prefab objects that I use to populate the scene on launch. They are background objects, and they never move. Both have a rigidbody and mesh collider attached, and both settings are the same. The only difference between the two is that one is a sweep object and one is an extrude object.

Until a couple of hours ago, both worked as expected – other rigidbodies would collide with them and stop. Now all of a sudden, other rigidbodies go right through one type, while the other type continues to work. Nothing has changed with these prefabs. Both have Is Kinematic = true and Use Gravity = false. Both have the same physics material and are identical in every respect. Makes no difference if I place these prefabs in the scene before launch, or instantiate them in code. Occasionally, if I quit Unity and relaunch it, they will work the first run, but then fail after that. I was using Unity 3.2 until a few minutes ago when I updated to 3.3. Made no difference.

One other thing I just discovered, if I turn Use Gravity on in the inspector after an object has been instantiated, it works. But if I turn it on for the prefab before launch, it makes no difference.

What can cause a rigidbody to be ignored by other rigidbodies?

2

Rigidbodies should only be used for objects that move. Not that it should make any difference as far as interaction goes…maybe something was changed with the ignore layers? (If you’re using them.)

–Eric

3

What should be used for stationary objects? How do I make, for example, a wall that other objects cannot go through?

Everything is in one layer. The only other layer I’m using is for the GUI.

4

I think I see what you are talking about. I removed the rigidbodies and left the colliders, and it now works again. I guess I don’t really understand why this would work, as I thought both were needed for physics interactions.