Gelato can be a compellingly powerful renderer and rippingly fast when it works. All images © NVIDIA Corp.

In the relatively slow-evolving field of 3D graphics software, it’s remarkable to see the recent surge in stand-alone 3D renderers: Turtle, Vray, Brazil and new versions of RenderMan from Pixar. Each has its advantages and proponents, and each has a common thread. All of them depend on a computer’s CPU for processing power. With these renderers, every processor you add to a 100 CPU render farm will increase your rendering power approximately 1%, notwithstanding the overhead of increased network traffic, and the additional cost of a rack-mount server, large quantity of memory and so on.

NVIDIA’s Gelato, which is designed to compete squarely with Pixar’s PRman, is a horse of a different color. (PRman is a highly-evolved renderer based on the general RenderMan specification, and sets the standard against which all RenderMan renderers are measured.) Gelato is written specifically to harness the dedicated 3D processing power of NVIDIA’s graphics processors, or GPUs — more specifically, the high-end graphics horsepower of its top-end Quadro FX graphics cards.

Since Pixar’s PRman is so well established in the industry, and widely regarded as so supremely powerful, the chief arguments for using an alternative is cost. PRman starts at $3,500 per license and escalates from there for the full RenderMan Artist Tools toolset, which costs $2,000. Add to this $4,000 for a typical dual-processor server or workstation with 2GB or more of RAM, and a typical 200 CPU renderfarm, configured with rendering software, will set you back more than $1 million, plus substantial annual licensing fees for upgrades and service.

Creating scenes to use Gelato is transparent if you let the included plug-in, Mango, automatically translate your Maya shaders, but it’s real speed advantage appears when using custom Gelato shaders.

The cost per workstation for Gelato is very closely pegged to that of RenderMan: the software itself is $2,750 per client, while a high-end Gelato workstation runs between $4,000 to $8,000. So the real question is, can Gelato hardware/software really replace the render farm?

One key to the question of Gelato’s economy of scale is whether Gelato really works as a complete replacement for software renderers and large distributed render farms. If you can replace a 200 CPU renderfarm outright with a few copies of Gelato on a bookshelf worth of workstations, it’s a winner. But if your project involves elements, say rendering software-based effects that won’t render with Gelato, or if you also distribute network rendering tasks such as compositing, then you’ll be stuck buying a $1 million farm and adding as many licenses of Maya or some other software renderer, anyway. That’s not to say you can’t supplement a traditional renderfarm with Gelato servers that can render Gelato jobs when needed, but that’s not nearly as enticing as being able to choose one or the other.