:-) Select all the objects in your scene. Then click on the small down arrow next to the 5 render buttons. Clcik on Render Options and you'll see that the default is "no Mask". Change that to "Object Mask" then render the scene. You'll get a black and white scene. The objects in white and the background in black (it'll make sense when you do it. If you put both this picture and the normal one into photoshop, each on a different layer, you can then use the magic wand on the mask picture to get an outline marquee around your objects, which you can then cut and paste like normal. Hope that helps. if not, I'll explain in more detail.

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Phillip Drawbridge
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