Well, this way is good for reduce the time of render but shadows... Somewhere in this thread I see the plugin that remove unused (invisible in render) poligons/vertex etc from scene but now i cant't find it. Any suggestions?
@celtic1138 mentioned "Scene Optimizer." My understanding is that the way that plugin works is that it reduces the resolution of the textures involved in a scene, which means that they will take up less room in your GPU, possibly letting you GPU render a scene that would otherwise exceed the size of your GPU memory. The polygons that make up your scene are usually much less of a load on your system than the textures, and Iray is pretty good at figuring out what isn't visible and what is. That's not to say that "turning off" stuff that doesn't show won't help, of course, but having extra geometry in your scene is probably not the primary cause of slow renders, or of exceeding your GPU's memory.
I don't know of a plugin that will eliminate non-visible "stuff," but you can do it manually just by clicking on the little "eye" next to items in the Scene tab that aren't visible. Of course, sometimes something that isn't visible still affects a scene - a ceiling may not be visible in a shot, but it still blocks exterior sunlight, for example. That's probably why there isn't an "automated" way of doing this - hard to figure out "what doesn't affect the scene" and what does.