When I measure up a van I use the "put a known length object" in the picture and scale off that. I havea one metre metal rule I use and put it between the wheels on the ground and when scaling into corel I scale it up that way. When working around wheels (ive only done two vans) if youve scaled correctly when you cut etc it should be right if yu took pic dead on side on, hope that makes sense, makes sense in my head. But thats a scary place too
Does that help?
Steve, the point I'm alluding to is that he has a question, and is not clear, to me anyway what his problem is. If explained better, more people might be able to help him more readily instead of maybe avoiding the thread because they either can't or don't want to be able to be bothered.
Spury if you want to know how to chop selections from a selection, there are books & tutorials, or just use the alt key (in P'shop) to subtract a second selection from a former one. You don't say whether you just bought photoshop cs, or whether it's Illy (Illustrator CS) that's your stumbling block, or whether you've ever used either one in former versions before...
There might even be tutorials, videos or pfd help files with your software.