Environment rendering optimization for Pixar's the good dinosaur

The vast environments for The Good Dinosaur cover miles of terrain with procedurally generated geometry and instanced vegetation assets. Early sequence profiles revealed large memory costs attributable to tracing offscreen trees. Given the variety of vegetation in a set, many assets were not repeated enough to be instanceable and some instances only appeared offscreen. Our rendering procedurals employed both stochastic and frustum pruning. However, ray traced objects were excluded from frustum pruning or a large buffer was applied to minimize shadow popping. Stochastic pruning was still applied but as if the object was onscreen.