Answers to questions about RenderMan!
What’s new in RenderMan?
First, RenderMan itself is new! Over the past few years, RenderMan has been reengineered into a totally new renderer, and is today the most modern and advanced film quality renderer available. The foundation of the new RenderMan is based on a highly-optimized method of rendering global illumination which can ray trace scenes consisting of heavy geometry, hair, and volumes with both world-class efficiency. Photo-realistically accurate, RenderMan’s latest technology offers the very best-of-class in rendering for both VFX and feature film animation.
In combination with RenderMan’s intuitive system for physically based rendering, artists can quickly create photorealistic imagery and dramatically accelerate the process of lighting and look development.
What are the latest features in RenderMan 21?
RenderMan 21 is a major release that advances the totally new renderer introduced in RenderMan 19. A major feature of the release is the introduction of the same shaders and lights used at Pixar, providing artists with access to the tools for look development and lighting used in “Finding Dory” and its accompanying short film “Piper”. Also new to the release is the Pixar Surface Collection, an expansive catalogue of physically based materials and lights, allowing artists to quickly create images at the highest levels of quality. In addition, a streamlined GUI and GPU accelerated denoising are among many powerful new features. Much more information on RenderMan 21 can be found here.
Is RenderMan hard to use?
A; Not at all! the latest RenderMan has been specifically developed to provide artists with simplified and easy to use controls for shading and lighting through the most advanced global illumination methods available. With full support for single pass workflows, RenderMan simplifies the process of managing and rendering complex shots. RenderMan’s catalogues of standard lights and materials and simplified interface to popular authoring applications such as Maya, elevates traditional VFX workflows to even greater levels of efficiency, allowing artists to freely express their creativity.
Does RenderMan support IPR or interactive rendering?
Absolutely. For lighting and look development, RenderMan offers a state-of-the-art system for interactive rendering that dramatically increases the throughput of production scenes while allowing artists to focus on the art of lighting. RenderMan’s progressive rendering engine scales up to extremely large scenes and supports the editing and manipulation of lights, shaders, and the scene camera.
How new is RenderMan really?
RenderMan’s has been completely re-designed from the ground up to be easy to use while generating production-quality renders fast and efficiently. In particular, RenderMan provides an elegant framework for advanced light transport through two highly optimized methods: a unidirectional or forward path tracer, and an innovative VCM unified rendering algorithm which is able to integrate bidirectional path tracing with photon techniques to produce results of higher quality than either might do alone. RenderMan provides a framework for swapping between the most appropriate types of light transport for any particular scene, an area where RenderMan is unmatched in the industry. Additionally, new methods of light transport can be elegantly added to enable RenderMan to quickly take advantage of future research and development.
What is the difference between unidirectional path tracing and VCM?
With unidirectional or forward path tracing commonly used for creating global illumination, the ray follows a path from the camera to the objects in the shot. VCM is different as it integrates bidirectional path tracing and photon techniques so that the rays follow two paths, one from the camera and one from the light source. The result is a deeper understanding of where the light is relative to everything else in the shot, making it easier to sample difficult lighting effects efficiently in a noise free fashion. RenderMan’s new VCM method of light transport is particularly suited for solving these notoriously difficult shots fast, efficiently, and with high fidelity.
Why would I use unidirectional path tracing if I can use VCM?
For many types of shots, the benefits of VCM may not always offer significant advantages and unidirectional path tracing will be sufficient. An analogy is to imagine a ray-traced shot as a maze. One way to solve a maze is to start at the entrance and keep trying different paths until you reach the exit. If the maze is simple enough this is an efficient way of finding the right path. Unidirectional path tracing is like this with the camera at the entrance and the light at the exit. For really complex mazes however, a better approach is to find the right path by working from both the entrance and the exit, and find a way to join in the middle, and this is essentially what VCM does. Both approaches will eventually find the right solution, but working from one end only may take much longer in a complex maze, while in a simpler maze working from both ends will not find the path any more quickly.
What kind of ray tracing performance does RIS deliver?
RenderMan has been redesigned from the ground up to provide a framework for casting rays as efficiently as possible and the support for BXDF's written in C++ is one example of this highly tuned system. However, every shot is different and it is often true that the performance of two highly tuned renderers will produce a similar picture in a similar amount of time. In general, outdoor shots with extensive direct illumination are easier to solve efficiently than indoor shots with large amounts of indirect illumination. If the rendering time for a representative group of both indoor and outdoor shots is added up, then RenderMan can be expected to process the total sum of these shots more efficiently and within less time, even if individual shots may vary.
So how fast can I really render a frame?
Of course there is no easy answer to this question as it depends on the complexity of your data and a host of other factors. However a key tool in RenderMan is the denoiser post process, integrated into the software, and now GPU accelerated in RenderMan 21. It allows final quality ray-traced images to be resolved, often up to 10X faster than waiting for the renderer alone to converge upon final resolution. RenderMan’s forward and bidirectional path tracers are world class, and in combination with denoising provide the best of all worlds, and is comparable or superior in output performance to any other solution.
How is RenderMan going to develop in future?
Ongoing development of RenderMan continues to target very substantial performance improvements over what has been possible to date. Just as importantly, RenderMan will enable deployment into the production industry of future rendering technologies in development from the research efforts of Pixar and the broader Disney Studio organization. It is the coming together of different approaches to the problem of general global illumination embodied in the latest RenderMan, that establishes a foundation capable of addressing a whole series of future challenges in lighting and rendering.
What about the RenderMan REYES renderer?
The REYES renderer is no longer included in current and future versions of RenderMan. If you are still using REYES, don’t worry! We will continue to support REYES in separate builds of RenderMan 20 until at least 2019.
Is RenderMan still customizable?
Yes. RenderMan offers a full suite of production quality rendering Integrators that embodies not only RenderMan’s traditional flexibility and strengths, but takes them to new levels. In fact Pixar provides source code to the forward path tracer as standard. Other plug-ins with source access includes Bxdf, Pattern, Projection, displacements and more. Anyone can write their own rendering tools for the RenderMan platform.
Does RenderMan support GPU rendering?
The current version of RenderMan is a multi-threaded software application that generally does not rely on GPU's due to their additional expense and the current fluidity of graphics hardware and supporting software standards. However GPU's are an important aspect of the future direction of rendering that Pixar is currently researching, some of which has already demonstrated in public. For the first time, RenderMan 21 introduces GPU accelerated denoising, and as GPU's mature for comprehensive production usage, we will reveal more in future.
Is RenderMan implementing new open source standards such as USD, OSL, VDB and Alembic?
Yes. RenderMan includes open support for OSL and VDB. Pixar is also committed to supporting formats such as Alembic, ptex, OpenEXR, SeExpr, OpenSubdiv, as well as other industry formats. RenderMan is designed to allow easy integration of new standards as they come along.
What is the technology relationship between Pixar and Walt Disney Animation Studios?
Key technologies seen in recent Disney feature films such as advanced de-noising technology are also a part of RenderMan. Cross pollination of technical development and production know-how is ongoing as part of Disney / Pixar's commitment to the advancement of RenderMan as the long-term film rendering standard.
What CG authoring solutions are supported by RenderMan 21 right now?
RenderMan is currently compatible with versions 2015, 2016, and 2016.5 of Autodesk’s Maya and with versions 2.0, 2.1, and 2.2 of The Foundry’s Katana. Compatibility with Side Effects Houdini version 15.5 and versions 2.77+ of the Blender Foundations Blender software will be announced shortly. Maxon's Cinema4D connectivity will be available later in 2016.
Is Maya LT compatible with Non-Commercial RenderMan?
No, due to plugin restrictions within Maya LT. RenderMan is supported by standard Maya or with free 30 day trial licenses of Maya available from Autodesk.
What other authoring solutions are on the RenderMan roadmap?
The following table summarizes authoring application connectivity as of summer 2016:
RenderMan Bridge Compatibility
Supported Support Underway
Blender. . . . . . . . X
Houdini. . . . . . . . X
KATANA . . . . . . . . X
Maya . . . . . . . . . X
Cinema4D . . . . . . . . . . . . . . . . . . . X
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