Thanks for your answer - layer linking I have used before, but the problem is I can't send these complete drawings to clients because the linked view takes to much time to render...so I put a bitmap of my rendering (screenshot) next to the top/plan view as a 'fake' linked layer.
This doesn't help my biggest problem though- the vanishing point thing. It's only in some drawings, but I don't know what causes it. Normally you're able to render things in different layers at the same time- with shaded polygon, and a correct vanishing point...