Bump is more expensive because we need to evaluate the input 3 times instead of 1 to compute the orientation of the normal (tip by Pixar's Philippe Leprince) The only cost is loading the texture tile, which is amortized by RenderMan's texture cache. It is best to use normal maps when possible because normal maps encode all required values in the RGB channels. The fabric is meant to be synthetic, so we've used iridescence to give it an otherworldly feel, combined with some fuzz and a normal map, we have a strange-looking, but robot friendly fabric. Suggested tutorial on Linear Workflow in RenderMan Check it out >
It's very important to keep color management (gamma correction) in mind, or we will get inaccurate lighting results. When using textures to drive data inputs, such as roughness or bump, there is no need to linearize. This will convert the color profile from sRGB to Linear, which will provide accurate representation of color and lighting. When we use typical 8-bit color textures to drive color channels in our shader, we need to make sure we set our PxrTexture to Linearize. I've chosen PxrTexture for this scene, but you might want to use the Maya file node for better viewport feedback. The diffuse maps can be hooked up to the shader with a PxrTexture node or a Maya file node, RenderMan supports both natively. We can do this by adding some roughness to PxrSurface, this gives surfaces a micro-facet diffuse response thanks to RenderMan's Oren-Nayar diffuse model, instead of a traditional Lambert model, which is designed to simulate perfect diffusion.and we all know most surfaces are not. In order to keep things realistic, I usually add a little bit of irregular diffuse response. Not everything needs to be shiny, especially since not having to calculate specular saves us rendering time. We are using simple diffuse surfaces to describe our walls and carpets.
Get started with RenderMan shading networks Learn More > Keeping shaders procedural allows us to tweak and extend them easily. The scene also uses native Pixar procedural patterns as much as possible, including paint flakes and several noise patterns. We are also using Pixar Surface Material (PxrSurface) for most of the scene, as it provides an extensive amount of controls for our surfaces. We are using textures downloaded from for most of the scene, including our wall. The technical goal of this scene, was to achieve realism in an interior setting without compromising speed, so I made objects clean and simple in order to rely on shading detail. We also touch on several crucial compositing features, such as AOVs, LPEs, Light Groups and Deep Data compositing. The scene was created to take advantage of many of the production-ready features in RenderMan for Maya and their integration with Nuke and Fusion, including various Pixar Surface materials, Maya Paint Effects, Daylight simulation, IES profiles and Volumes. Robot Room started as an interior study for indirect illumination and progressed into a scene with a robot couple taking a break while building their first robot son.what can I say, I like robots.
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