The harsh lighting on this AAT battle tank does not yet match the lighting in the background plate.
The CG tank model must be lit in the same way that our real set was lit in order for it to blend into the scene. David Dozoretz examines the fall of shadow on the actor to determine where the sun is in the sky. He adjusts the placement of his CG light source accordingly, until the tank model is lit just as if by the same sun.
CG lights do not act like real lights. They do not automatically provide for auxiliary effects, and the animatics artist must step in to model physics such as light bounce, color modification, haze, and so on. Generally, a minimum of three different CG lights are needed to create an acceptable effect for the animatics.
Sophisticated lighting consists of a complex of different lights, including the principal ("key") light, fill lights that make shadows less harsh, scattered ambient light, and so on. For outdoor shots the key light is normally the sun. However, scattered light plays a large role in lighting as well. Enough of this must be matched in the CG world to blend the animatic and real elements.
