Detecting collisions without rigidbody

Questions & Answers
1

I have a car with the following aspect:

...

As you can see, colliders are locally static, because they are separated from the original rigidbody component.

Well, as you can suppose, I have a problem, because MonoBehaviours with an OnTrigger(…) or an OnCollision(…) method won’t work. (It needs an rigidbody and a collider on the same object)

I thought about Raycasting:

But I have another problem, I have to specify a direction, so, using this: http://answers.unity.com/answers/539155/view.html isn’t an option because this is too slow?

What can you suggest me?

2

as long as those colliders are children if the rigidbody, it will receive the collision calls because they combine to a compound collider: