As renderers get more powerful, more detailed work is required, as is evident in this shot rendered in Gelato. © NVIDIA.

Blame It on Blinn
“Rendering times are still high because any time renderers or hardware speed up, users just make scenes more complex,” observes David Wilton, product manager, NVIDIA professional software. “‘Blinn’s Law’ was created years ago to explain this situation — the average studio typically has an established threshold for the time it takes to render a frames. As hardware becomes more powerful, these studios use this power to make their frames look better, not faster.”

In addition, companies are always coping with scalability when it comes to keeping pace with changing technology. “With rendering, scalability is the ability to handle increasingly complex data sets,” explains Pixar’s Ford.

“It’s fairly easy to create a renderer that will handle small scenes or perform very specific functions well at the expense of doing others poorly,” adds Gritz. “It’s very hard to design a renderer that will handle huge scenes across the entire range of requirements found in a studio environment. Most frustratingly, tools that handle the most difficult cases usually are much slower than tools that only handle small cases, because they must be more general and robust. So often users are faced with a choice of fast or scalable.”

Grant of Digital Domain touts the current big push from 32-bit to 64-bit processors. “It seems companies have to upgrade every year,” he says.

“Scalability involves both managing the number of machines and the amount of data,” adds Regelous. ”We need smarter ways of representing data than what the industry has been focused on to date: writing out big files.

In Massive, we’ve addressed scalability by providing a highly efficient RenderMan-compatible rendering pipeline that is able to handle hundreds of thousands of film-quality humanoid characters in a scene. With GPU rendering, we are now also making creation of these types of large-scale scenes accessible to smaller studios, who until now have not had a way to render such things.”

As seen in Gelato, new renderers can handle tasks like hair and subsurface shattering much easier than before. © NVIDIA.

Harnessing the GPU
“We see a definite trend in using GPU hardware [video card] processors to help speed up the rendering,” notes Brazil’s Kirvin.

“Professional graphics processing units (GPUs) been around for quite some time,” echoes Gritz. “NVIDIA Quadro products have been available for almost six years. In the past, an artist would leverage the GPU when doing much of the preview and animation work before sending off their image to final render. This final render was done entirely using the CPU. In fact, many artists would pass the time waiting for a render by playing a game, which would run on the GPU.

“Gelato was engineered from the ground up to leverage both powerful processors in the computer — the CPU and GPU. By offloading tasks normally all handled by the CPU to the GPU, you can create final rendered images faster. While the results vary by the scene, we are seeing, on average, about a 2x speedup on final rendering when comparing Gelato to CPU only film renderers,” Gritz stresses.