B) What you are looking for is this:
why don't you just set the renderer.enabled= false;? That will make Unity forget about rendering that object and it will be invisible, un-interactive, un-responisve, etc. It'll be like it never existed until you reset the renderer.enabled to true again. So write the code, but if what I illustrated is what you are looking for then you at least have a hint of where to start.
answered Jul 20 '10 at 04:28 PM