void Awake()
{
myRigidbody = rigidbody;
previousPosition = myRigidbody.position;
minimumExtent = Mathf.Min(Mathf.Min(collider.bounds.extents.x, collider.bounds.extents.y), collider.bounds.extents.z);
partialExtent = minimumExtent * (1.0f - skinWidth);
sqrMinimumExtent = minimumExtent * minimumExtent;
}