rotating/moving colliders with or without rigidbodies?

Hi

Im making a Cog that has to rotate.

Empty GameObject with these children: - 1 spehere+collider - 3 boxes with colliders

Im losing 10 fps on iPhone when I have 2 of these rotation in update. I also tried adding rigidbodies but performance didn't come back to max.

Any suggestions or how can I rotate objects with colliders?

//// Code ////

private var thisTransform : Transform; var zRotate : float = 1;

function Awake () { thisTransform = transform; }

function Update () {

thisTransform.Rotate(0,0,zRotate);

}

As a general rule, If you have GameObjects with colliders, and you intend to move them, always add a kinematic Rigidbody. Colliders without Rigidbodies will go into an accelerated AABB Tree in PhysX for fast collision lookups, but this tree has to be rebuilt every time a collider is moved, which will kill your frame rate.

but should I add a Rigidbody to each child object (with colliders) or only to the mother (Empty gameobject) ? Or both?