Thanks! I didn't know about the mask render in kerky but I will give that a try.
(what do you think of the modeling by the way? Bridge concepts always seem to be white now)
Updated: I tried the mask render in kerky and it gave a pretty good mask that I could use in photoshop to "cutout" my bridge and place it into a background photo. I will try the match photo in sketchup and then rendering in kerky. If that makes sense.
I would still be interested in web tutorials that show examples of adding models to real images. I am very new at making models and photos mix.(for shading help, making it look real, etc)
Update 2: Just a quick render and photomatch for the bridge shown above. I need shading, scale, etc and the angle might not be correct but I think I am on the right track..
Thanks for the help!
s
crossbow1.jpg