I need urgent aid with ogreode and picking 3d. I have read everything what I have been able, but nonencounter answers

In my application, I have objects in ogreode, for example those of an example of demonstration of ogreode, and I have coordinates x, y, z and the radius of a control ball.
This sphere is the indicator of control of a laser system in the real world, and the objects in the world are objects of the real world.
The problem: how to find out that the sphere can take an object with ogreode? It is possible? That properties must have the sphere so that does not bother to the objects of the scene?
If I puts values to him of density, mass.... to the sphere, when it happens over an object modifies it, moves it, and I do not look for that, all the opposite: the sphere must cross the objects without modifying them.

But if I do not put characteristics of ogreode to the sphere, masses or similar, I cannot detect collisions. And if I detect them, the contact object moves, or changes its position, or the control ball moves, things that I do not look for.
At the moment, I am implementing the algorithm of distances between center of the sphere and the center of the object, but I think that ogreode would have of being able to solve this, but I do not know how to do it.
Possibly this already has been solved, but I have looked for in the forum (including ogreode thread), and I have not found it

Any aid will be welcome

Thanks in advance