If you`ve looked at various rendering engines (very important to create a 3D configurator) on the market or been informed about stand-alone rendering solutions, you`ll probably have come across terms like biased vs. unbiased, GPU acceleration, REYES or Monte Carlo.
The latest wave of next-generation renderers has generated a lot of attention, but it can sometimes be difficult to tell the difference between a marketing buzzword and a real feature.
We`ll take a closer look at the terminology used in the following article so you can see things from a clearer perspective.
What is the difference between biased and unbiased rendering?
Discussing what biased or unbiased rendering is can quickly become technical. In this article, we want to avoid complexity and keep the topic as simple as possible.
Unbiased renderers like Maxwell are usually called “physically accurate” render engines. Although the term “physically accurate” is something of an error, it is intended to imply that an unbiased renderer calculates the path of light as accurately as statistically possible within the limits of current rendering algorithms. In other words, no systematic error is deliberately introduced. Any variance will manifest itself as noise, but with sufficient time, an unbiased renderer will eventually move towards a mathematically correct result.
Biased renderers, on the other hand, make certain concessions in favor of efficiency. Instead of letting the time pass before a solid result is achieved, Unbiased renderers introduce an example bias and use subtle interpolation or blurring to shorten the render time. Biased renderers can be fine-tuned compared to Unbiased renderers, and in professional hands, an Unbiased renderer can possibly produce an absolutely accurate result with significantly less CPU time.
Ultimately, you have the choice between an Unbiased renderer, which requires more CPU time, but relieves the 3D artists, and a Biased renderer, which gives the artist a little more control, but in return requires more time from the renderer.
Although there may be some minor problems. Unbiased renderers work quite well for still images, especially in the area of architectural visualization. For motion graphics, movies and animations, however, the efficiency of a biased renderer is usually prefereable.
What about GPU acceleration.
GPU acceleration is a relatively new development in rendering technology. Game engines have relied on GPU-based graphics for years, but only recently has CPU integration been explored for use in non-real-time rendering applications where the CPU has always been the focus.
However, the widespread use of Nvidia`s CUDA platform made it possible to use the graphics processor together with the CPU for offline rendering tasks, leading to a new exciting wave of rendering applications.
GPU-accelerated renderers can be unbiased like Indigo or Octane, or biased like Redshift.
What about RenderMan?
In a way, RenderMan is a little off the beaten track. It is a biased rendering architecture based on the REYES algorithm developed more than 20 years ago at Pixar Animations Studios.
The following video shows the basics of using RenderMan:
RenderMan is deeply rooted in the computer graphics industry and, despite growing competition like Arnold, will most likely remain one of the best rendering solutions in high-end animation and effects studios for many years to come.
RenderMan is so popular, but why do you hear so little about it?
Because it just wasn`t designed for the independent consumer. Take a look around the online community. You`ll see thousands of images of unbiased raytracers like V-Ray and Mental Ray or unbiased packages like Indigo, but it`s rare to find anything built into RenderMan.
When designing RenderMan, it was never intended that the render engine would be used by independent 3D artists. While V-Ray or Indigo can be used very competently by a single artist, it takes a team to use RenderMan as intended. RenderMan was developed for large pipelines in production.
What does all this mean for end users.
First of all, it means there are more options than ever before. Not long ago, rendering was a bit like black magic in the world of computer graphics, and only the technical artists had access to the key. A lot has happened over the last decade, so that photorealistic results can be realized by just one person.
Newer solution like Octane or Redshift are so different from old ones like RenderMan that ir makes almost no sense to compare them.
Thanks for reading.