How V-Ray for Nuke elevated a stylized animation pipeline

Frank Rueter reveals how adding V-Ray for Nuke to OHU Domes’ pipeline helped the small team produce a new level of quality across three short planetarium films.

Frank Rueter worked for several years at large VFX companies including Weta Digital and Digital Domain before starting OHUfx. (“Ohu” is Māori for “cooperative.”) Now, his role shifts according to what is needed for any given project. “Sometimes I act as the VFX supervisor — post side or on the client side — and at other times I help out with Nuke-/Hiero-based pipeline development,” Frank says. “More often than not we are asked to simply help out with shot compositing, and sometimes it’s all of the above.”

Designing a short film for a planetarium

When the team did the first show — a version of "The Māori Creation Story” — it served as a technical exercise to see if they could do this sort of project efficiently. They had to figure out how best to produce and compose a hemispherical canvas, and most importantly they wanted to bring strong storytelling to the world of planetariums. The team’s experience using Nuke as an environment tool on feature films came in particularly handy for the task.

Since the OHU Domes collaborative was in complete control over the creative aspects, they shot for a stylized concept, to allow them to concentrate on the technical specs, as well as provide some restrictions while finding their feet. 

“The idea was to create an environment that resembles a theater stage with the audience located in its center,” Frank explains. “This approach avoided the need for complex CG environments and camera moves and, by contrast, was inspired by designs for puppet shows and pop-up books — and a little bit of Victorian stage craft.” 

The storytelling was of utmost importance to the team, and the art director, Matt Pitt, came up with several beautiful concepts for the characters of Tāne Mahuta, Tāwhirimātea and Tūmatauenga, the Māori gods that would take center stage.

The basic Nuke setup — pre-V-Ray

Character animation was handled by Matt in After Effects, using the Puppet Tool system, while Frank focused on creating environments inside of Nuke — which essentially consisted of concentrical multi-plane setups. 

“The various ‘stage levels,’ as well as the pre-rendered character animation, were constructed and combined via opacity-mapped cylinders, with custom AOVs to fake soft shadows in 2D,” Frank recounts. “Since there were very limited resources in terms of render capacity, budget and time, this had to suffice for the first film, and the simplistic style was somewhat forgiving of this old-school approach.”

And with four different views to deal with — front, back, left, right — Nuke’s multi-view pipeline, designed for stereo workflows, came in handy to keep the complexity of the comp scripts in check: 

How V-Ray made things a lot prettier — and easier

In the second film, “Rona and the Moon,” while staying true to the simplistic design style, the team wanted to take the visual quality further. It was time to deploy V-Ray for Nuke.

“[With V-Ray, we were] able to actually light the environment properly and get a more realistic feel to the stage, thus making the experience for the audience more engaging,” Frank explains. “This worked very nicely, although rendering was somewhat intense due to us still using opacity-mapped geometry — which is obviously not a good match for ray tracing.”

Generally, the lighting and shading setups were extremely basic, since the team was mostly seeking soft shadows and some GI. “But when Marama, the moon, had to disappear behind a stylized, cut-out cloud, I couldn’t resist playing up the translucency to make the cloud look more like wax paper as the moon light transmits and scatters through it,” Frank adds. “[This is] something that we could not have done with Nuke’s default renderer.”

“The additional benefit of using V-Ray was that I could render the entire stage directly to angular map format — our final delivery format — which greatly simplified the entire Nuke setup,” Frank continues. “[This way,] we could discard the multi-view, cubic-map workflow that we utilized on the first film, and saved ourselves the required conversion steps at the end.”

Experimenting with V-Ray for Modo

With the first two shows under their belt, it was time for the OHU Domes team to use their confidence with V-Ray — and get a little more adventurous. The result is their third short film, “The Great Waka of Tamarēreti.” 

“We wanted to feature V-Ray a bit more in our production this time, so instead of relying on opacity maps again, we decided to model the basic stage geometries in Modo,” Frank details. “We then imported all models and animation via Alembic and FBX into Nuke to render via the V-Ray plugin. This meant a longer lead up in the set-up phase, but much more control and flexibility for shading, lighting and rendering — not to mention more efficient render iterations and higher quality. We also started using V-Ray’s Cryptomatte features at this stage, which further sped up look development — and naturally grew into the final production setups.”

For The Great Waka movie, the team kept to the concept of a concentrical theater stage for the main storytelling parts, but started exploring a more complex setup for the opening and end shots. They used Modo to create a simple cloth simulation to mimic stage water. Matt additionally provided some models of various Wakas (canoes) to glide across the “water” surface.

“We generally tried to take our design cues from practical theater design, for example a camp fire was realized by having several pieces of cloth with a strong up wind — mimicking a fan — and a strong flickering uplight,” Frank confirms. “Using proper geometry and a seasoned raytracer, like V-Ray, inside of Nuke enabled us to do these things quickly — and always in the full context of the final frame.”

Rendering proxy quality was still important for the team to have a quick turnaround as well as more creative iterations early in the production. “For this, I hooked up proxy render settings in the V-Ray Render Node to Nuke’s Proxy mode via simple expressions, so that I could use the default proxy hotkey to toggle between draft and final render quality on the fly,” Frank explains. “It took a minute to set up — and saved me hours of time.”

You can view a trailer for the three films at www.ohudomes.com