Ray Tracing vs. Rasterization

Overview

In the thin lens equation, we have a model for how light strikes an image plane. The projection models cover how light propagates through a scene to reach our camera. Ray tracing is the next logical step: constructing an entire image by modeling light propagation through a 3D scene. We first cover ray tracing very briefly, as it is perhaps the most intuitive rendering technique and widely used in the film, animation, and 3D design industries. Then, we take a closer look at rasterization, a more efficient technique that PyTorch3D relies on.

The ray tracing algorithm

Ray tracing is a class of algorithms with many commonly known variations, such as path tracing and photon mapping. These techniques all have one thing in common: they form images by modeling the physics of light transport from various light sources to a given camera. Ray tracing can model all sorts of real-world light transport effects, including reflection, refraction, scattering, ambient occlusion, subsurface scattering, and more.