Awesome! I had been working on a similar project couldn't figure out the snow on the trees for the life of me! It's great to see how you approached it. The work look great! Thanks for sharing your process.
I believe author would be surprised that it's not american, but soviet bunker :)
SLiB Match 1.0 is a Maya plugin that mathematically calculates the camera viewpoint of a given background image and creates an oriented Maya camera that’s position and field of view perfectly match the perspective of the background image. This allows to place 3D objects inside your maya scene as if they were part of the background image.
Other features of SLiB Match:
- intuitive gui
- save / load vanishing line positions for later use
- create camera projection shader with a single click
- one-click texture baking [Redshift only]
Focal Length estimation will be incorrect if the center of the image is not on the camera’s viewing axis or if the image was cropped non-symmetric. In this case you have to adjusting the Focal Length by hand.
You can find more info on the tool and get it for $30 here.