Rhythm & Hues Makes Skies Soar
November 27, 2012

Rhythm & Hues Makes Skies Soar

SANTA CLARA, CALIFORNIA — Global visual effects giant Rhythm & Hues (R&H) recently completed the lion’s share of visual effects shots on the acclaimed new film “Life of Pi,” leveraging NVIDIA GPUs to maximize throughput and accelerate creative workflows.

“Life of Pi,” from Academy Award-winning director Ang Lee, tapped legions of R&H artists at offices in Los Angeles, India, Kuala Lumpur, Vancouver and Taiwan to create several hundred visual effects shots in stereo 3D that included the Bengal tiger, digitally recreated water and skies, Meerkat Island and myriad additional creatures and effects. (For an in-depth look at the creation of the effects, see the December issue of CGW.)

R&H is known for its custom development of proprietary visual effects tools, many of which are written specifically for the GPU. One of those tools, dubbed Rampage, was particularly instrumental in achieving the remarkable skies that set the tone in this tale of an Indian zookeeper’s son named Pi, shipwrecked with a Bengal tiger and adrift in the Pacific Ocean.

Rampage is a 3D projection-mapping program that allowed R&H artists to quickly replace the skies in each shot with custom-made matte paintings. “We wouldn’t have been able to do this show without Rampage and NVIDIA GPUs. We were generating full HDRI [High Dynamic Range Imaging] skies with an average file size upwards of 3GB, which are the largest matte paintings we’ve ever done on this scale, not to mention the added complexity of creating them in stereo 3D. That high-resolution level of detail was required because the skies take up much of the frame in many scenes, and were used to light and influence reflections in the CG water,” explained Heather Abels, Matte Painting Lead.

From vibrant blue to sun-drenched, magic hour, tumultuous and stormy, over 110 different skies literally set the stage in this movie. With Rampage running on NVIDIA GPUs, artists were able to quickly project custom 2D matte paintings onto simple 3D geometry and review in real-time how each sky would look, aligning with the vision of the director and VFX supervisor, and creating immediate lighting reference images to hand off to other teams of artists.

Nathan Cournia, Lead Software Engineer at R&H, took an interest in writing code for the GPU to meet the project’s workflow and productivity demands. “The mandate in my department is to make things more efficient so that we can work faster and more cost effectively without compromising image quality. With each new show we create a priority list to guide our development. Oftentimes, as with ‘Life of Pi’, those demands drive us toward custom GPU development. For R&H working on the GPU means working with NVIDIA; their driver stability is simply better than the competition.”

In addition to Rampage, R&H has several other customized GPU tools that were used on “Life of Pi” including its in-house compositing package, Icy, with several nodes written using CUDA, NVIDIA’s parallel computing architecture, to enable real time color correction operations, retiming and optical flow. CUDA has proven to be popular with R&H engineers due to the abundance of easily accessible documentation available online. The CUDA based optical flow implementation garnered a ten-fold increase in performance over R&H’s legacy CPU implementation, enabling artist to converge quicker on the desired look. Likewise, R&H’s GPU-enabled proprietary animation and tracking software, Voodoo, continues to enjoy performance increases with each new generation of NVIDIA GPUs.

“It is an honor to have NVIDIA technology associated with such an incredible film; one that so seamlessly marries masterful cinematography with incredible visual effects,” said Greg Estes, Media and Entertainment Industry Executive, NVIDIA. “The effects in this film, from skies to water to a living breathing tiger are entirely photo-real and deeply complex from a computing standpoint and we’re pleased that the NVIDIA GPU contributed to the success of this feat of digital artistry.”

Cournia is continuing to write new GPU tools at R&H and is currently working on a large-scale development effort called Crom. Crom makes heavy use of the GPU and is a platform on which R&H is developing new pre-lighting, lighting and compositing tools. R&H is integrating its current CUDA toolset into the Crom platform, which is being deployed on the studio’s current projects: “300: Rise of an Empire,” “The Seventh Sun,” “R.I.P.D.,” “Percy Jackson: Sea of Monsters.” “Django Unchained,” “Black Sky,” “Grown Ups 2” and “Winter’s Tale.”