Introduction to RIS
Introduction to RIS
The RIS technology in RenderMan is a game-changing rendering paradigm, a highly-optimized framework for rendering global illumination, specifically for ray tracing scenes with heavy geometry, hair, volumes, and irradiance with world-class efficiency in a single pass. This evolution in technology offers best-of-class in rendering for both VFX and feature film animation. Today RenderMan is the most flexible, powerful, and reliable tool for rendering cinematic imagery.
For visual effects artists, RenderMan has never been more accessible and efficient. Today there are many options for integrating RenderMan into VFX pipelines, including solutions from Pixar for both Autodesk's Maya® and The Foundry's KATANA®. For lighting and look development, RenderMan offers a state-of-the-art system for interactive rendering that is capable of dramatically increasing the throughput of production scenes while allowing artists to focus on the art of lighting. The intuitive system for physically-based rendering allows artists to create the most photorealistic imagery conceivable.
State-of-the-Art Ray Tracer
RIS was designed from the start to trace rays as fast as possible. Period. With a new framework consisting of integrators, BRDF's (written in C++), and intelligent light services, RIS is setting new standards for both speed and memory efficiency when rendering multi-bounce global illumination for complex production scenes.
Progressive Rendering & Image Check-Pointing
The progressive renderer in RIS delivers incremental feedback for an entire frame all at once, continually refining the image until it reaches final convergence. The first pass of a progressive render is fast and rough, but captures all scene elements, including hair, volumes, motion blur and bokeh. With RIS, batch renders can be check-pointed after a specified amount of time or passes, allowing the image to be reviewed. The image can be stopped if something needs fixing or left to continue. By submitting an entire sequence to the render-farm, that entire sequence can be check-pointed allowing the animation to be reviewed at an early stage.
Interactive Lighting and Look Development
For lighting and look development, the raw power of the core ray tracing engine delivers fast interactive sessions for artists. Artists can now quickly light scenes and construct shader networks with immediate feedback. In combination with single pass workflows, lighters and shaders can super-charge their productivity.
Video: Interactive Rendering
Light Transport & Integrators
Integrators allow RenderMan to support arbitrary methods of light transport and are a key feature of RIS. Integrators take camera rays and return shaded results to the renderer. By supporting multiple integrators, RenderMan is capable of rendering the broadest range of effects, and with a comprehensive API for the development of custom integrators, the possibilities of the RIS system are vast. Out-of-box, Pixar provides two production-quality integrators:
The Path Tracer
Ideal for outdoor lighting and large direct light sources, this industry standard unidirectional path tracer combines samples from materials at hit points with light samples to estimate direct lighting, then spawns additional rays to handle indirect lighting. The path tracer ships with source code for further customization.
The VCM Integrator (Bi-Directional Path Tracer)
For scenes problematic for unidirectional path tracing, the VCM integrator can save the day. In addition to tracing paths from the camera, bi-directional path tracing also sends rays from light sources and then connects them. VCM can resolve complicated indirect paths and caustic effects that may be prohibitively slow to converge with unidirectional path tracing. Ideal for rendering interiors with complex lighting setups and caustics, VCM is a valuable tool to have at your disposal.
Global Light Sampling
Global Light Sampling is a method of pooling light samples for all sources in a scene, dramatically increasing the number of lights that can be used at any given time. In fact, with Global Light Sampling 1,000s of lights can be deployed in heavy production scenes at a high level of efficiency. Lights are automatically allocated samples depending on their importance in the scene determined by their size, intensity, and placement to the camera.
Ray Traced Subsurface Scattering
The result of cutting-edge development with Disney Research Zurich, RIS delivers a fully ray traced solution for subsurface scattering with a sophisticated shader capable of producing photorealistic results, such as human skin. Fully compatible with interactive rendering, it's easy and intuitive to dial in complex looks.
Pixar has a commitment to developing and adopting standards for animation and visual effects. RenderMan's support includes the following popular open standards: Alembic, OpenColorIO, OpenEXR, OpenSubdiv, OpenVDB, OSL, RSL, SeExpr, Ptex, UDIM, USD and others.
You don't want your shaders to limit your creativity, and that's why RIS ships an advanced shader library for creating the widest range of physically accurate looks possible. Better still, the shader libraries leverage the full power of the RIS ray tracing engine, with BRDFs optimized for computationally expensive global illumination effects. The only limit is your imagination.
• Multiple Importance Sampling
• C++ BXDFs
• Geometric Area Lights
• Gobos, Blockers, etc.
• Emissive Geometry
• Camera Projections
See RenderMan in Action
Join the teapot and take a tour of RIS, in the
Walking Teapot Music Video rendered in RenderMan version 19.
"Today Pixar launches the newest in that long line of innovations, a new rendering architecture known as RIS, that supports plug-in integrators and comes complete with a new industry standard path-tracer as well as a cutting-edge bidirectional path tracer.”
"This truly brings the future of fully photorealistic ray traced rendering to RenderMan. We did tests with the production assets from one of our latest movies and were completely blown away by the speed and how interactively we could preview and render these assets. The RIS based integrator is going to change the way we work, with more scalable rendering and faster results.”
Global Head of Lighting at MPC
"The new RIS is very fast, very stable, and very simple to use. I got great results within my first 2 hours. This new version is going to be a game changer and I'm thrilled to be using it.”
Creative Director at Rockstar GFX
"Pixar has really outdone itself with RIS for Renderman 19. The speed, quality, and ease of use that the new substrates bring are mind-boggling. You can setup a character in a shot fully knowing that the nature of the shaders won't change with lighting. It speeds up the look development process significantly.”
Lead Artist at Bad Robot Productions