- PxrMeshLight - The mesh light uses a piece of geometry and turns it into a light source. This is much more efficient than using glow or emission from a bxdf. It's great for things like neon lights.
Lights also have some special parameters regarding shadows and bidirectional path tracing made possible by the PxrVCM and PxrUPBP integrators. You can refer to the technical memo:
- Christophe Hery, Ryusuke Villemin, Florian Hecht. Towards Bidirectional Pathtracing at Pixar