Es que yo no he dicho que sea ni con softimage ni con mental ray. Por ejemplo si mirais octane o fryrender es a lo que me refiero. Esto es de la pagina de Octane:
Octane Render is the worlds first GPU based, un-biased, physically based renderer. As opposed to the handfull of processor cores available in CPU's, the GPU typically has hundreds of cores for parallel processing making it the best resource for rendering in your computer. Yet, to date no other software makes use of it in the way that Octane does. With even a single mid-range GPU you can typically expect to see a 1000%-1500% (10X to 15X) speed increase over a typical un-biased, CPU based renderer.