Collision Question - RigidBody a must?

Unity Engine
1

I know this question can be answered in two seconds if I had unity in front of me.
But I’m going through some code, which apparently assumes that all colliders must be attached to a rigidbody if they are to be detected in a collision.

I don’t believe so, but just wanted verify this real quick.

2

At least one of the two needs a rigidbody for collisions to register at all and if both need to be able to exert collision forces on eachother (like for instance 2 balls in a game of pool), both will need a rigidbody.

The table at the bottom of this page shows some more information on what can collide with eachother: Unity - Manual: Box collider component reference

3

thanks