How to: Set collision for ray sensor, but not for chassis

edit

Hi,

I would like to define models, which can be sensed by the ray sensor, but can not collide with each other.

A simple example is attached. Here I want to sense permanently the corner of the red Object, while I am driving through the object. Now the problem appears, if I set the collision parameter of the red object. If they are <pose>0 0 0 0 0 0</pose>, the robot can drive through the object, but the ray sensor can not sense it. On the other hand, if I set the collision to the same values as the visual parameters, the ray sensor can sense to corners, but the robot can not drive through.

How can I set the right parameters, to sense the corners and dirve through an object?

Kind regards, tik0