Here is a shot I comped on our Short film, Small Sacrifices.
The stop motion footage was shot on a motion control rig using the kuper system. Phil Created the Matte Paints in Photoshop. I then camera mapped them onto 3d geometry in Maya. The snow particles, I made in Maya. Their individual shapes are textures I scanned from little clumps of baking soda, which are randomly assigned to each particle. The rest of the compositing was done in After Effects. The fog was shot practically, in HD, the blue channel had to be removed, because it was noisy garbage. I then used the fog as a matte on a greyish blue solid so the fog could have a more even hue. We dropped a piece of black clay into the fog to have it react.
Here's a labeled version in case any of that was confusing.
In other news, Neil's posted some trailers of Small Sacrifices that can be see here.
And the Film's website will be up soon!