I would say this is impossible with photoshop, save compositing two shots (tracks and snow scene). If you have illustrator, then you can google brushes for tire tracks / tread and make a nice path and stroke it with the tread brush. Then bring it into PS and use the distort free transform to make fit the scene perspective. Then you can make that layer a channel so that its black tracks on white. Then duplicate your background layer scene and run lighting effects with your new channel as the bump map. Mask out everything but the new tracks and a bit of the surrounding snow. Looks great for a flat scene:
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http://www.pixentral.com/show.php?picture=1UsNt2yrzL7DyqduPD DOEmoaCz4mOh>
But if you have hills, then you need to use something to distort the tracks. I used a displacement map (you can google that) and basically painted white in valleys and black on the hills (on a 50% gray bg). But gets annoying and fiddly quick, and I can’t say for a scene like this it wouldn’t have looked better with flat tracks…
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The [only] problem with the method described above is the bump of the tread in snow does not get smaller with the perspective of the scene. Ideally you would have a flat gray, pop the treaded path on top of that, and apply lighting effects to it before running transform perspective, so that the perceived height of the tire marks got smaller.
J
