I have an ISceneNode and I want to modify some of the Z values of the points of this ISceneNode (after the load of the mesh). I found set Position, but it is for all the IScene and I want to interact only with some point and give different value.
An ISceneNode doesn't have any points [vertices]. IMeshBuffers have vertices. If you have a derived scene node that has vertices or exposes it mesh buffers, you can modify the vertices there or you can use a vertex shader to do it.