This R&D focuses on experimenting with the shader, lighting, and interactive rendering improvements in RenderMan 22, particularly within Houdini.

The main interest in this version was the interactive rendering and lighting workflow, rather than the introduction of a completely new primary surface shader.

For shading, PxrSurface remained the main full-featured production shader. It supported a wide range of material responses, including diffuse, specular, refraction/glass, subsurface scattering, and layered material behaviour. RenderMan 22 continued to improve the workflow around this shader rather than replacing it with a new flagship material.

For simpler physically based materials, PxrDisney was also useful, while PxrSurface remained the more flexible option for complex production look development.

One of the most important changes was the interactive architecture that allowed lights, materials, cameras, and geometry to be adjusted while the render was running. This significantly improved iteration speed for look development and lighting.

Light filters were also an important production feature, providing more control over the shape, falloff, colour, and contribution of lights without requiring additional geometry or complex lighting rigs.

The main goal of this R&D was to understand how RenderMan 22 could support a more responsive lookdev and lighting workflow, with faster feedback and more flexible control during live rendering.