Chocolate Tribe was responsible for over 90% of all the 140 VFX shots on Robot & Scarecrow, the latest short film from acclaimed UK director Kibwe Tavares. The film was co-produced by London based production houses, DMC Film (owned by Michael Fassbender and Conor McCaughan) and Nexus Studio. Starring Holliday Grainger and Jack O’Connell as the titular Robot and Scarecrow, this beautiful film tells the tale of a robot pop performer who meets a lonely scarecrow at a festival where they then embark on a whirlwind of experiences.

The production team approached Chocolate Tribe, a VFX studio based in Johannesburg, South Africa, to produce the cutting-edge visuals needed for Robot & Scarecrow. While this may seem like a radical geographical departure, Chocolate Tribe was uniquely suited to handle the work required for the film. The principle team from Chocolate Tribe for Robot & Scarecrow, Rob Van den Bragt and Tiaan Franken, have decades of experience working in both the South African and London visual effects industries, where Rob was a VFX supervisor with The Mill for close to 10 years. They could bring the best of both these communities together for the eight-month production schedule.

CRAFTING THE ART


Chocolate Tribe showed its versatility from the inception of the process, as the original plate photography had been shot three years before, at the Secret Garden Party festival in the UK. Working with pre-existing plates meant that Chocolate Tribe needed a proven and robust render solution.

The combination of Redshift’s GPU-powered speed and biased workflow made the decision to go with Redshift an easy one, as Tiaan explains: “Because of Redshift’s turnaround time on rendering and testing, that made a dramatic difference in crafting your art, rather than waiting on the renderer.”

Rob continues: “The capability of the renderer was of utmost importance. Yes, Redshift reduced our rendering overhead, but more importantly the render output was amazing. We ran various render tests with various rendering solutions. Together with the HDRIs from the set, the lighting model of Redshift with its physically correct shaders matched the non-biased renders in the majority of cases. Truth is, that biased renderers have been overshadowed a little over time by non-biased renderers, but in 95% of all cases, the difference is so marginal, that it often isn’t worth the substantial extra render time. What matters more is the physical correctness of the shaders and lights.”

Although Chocolate Tribe had eight months to deliver the project, due to the sheer volume of shots required, Rob was aware of the challenge that they had ahead. “It seems like a lot of time, but it’s not like you have two weeks to craft every shot. So we obviously needed something that worked fast, without sacrificing quality. Redshift delivered frames in two minutes; sometimes in less than a minute.”

These quick frames times were not because Chocolate Tribe was making any compromises when using Redshift. “These were with all the bells and whistles, we had depth of field, motion blur, GI, ray-tracing, SSS and high sampling even in our test renders,” Rob explains.

MAKING A SAVING


Chocolate Tribe found Redshift added economies of scale to workstations as well. Running dual NVIDIA 980tis would yield double the render speed of the significantly more expensive NVIDIA Titans running in single-card configurations.

Quite early on in production, when more GPUs were needed, NVIDIA had released new Pascal-based graphics cards. Chocolate Tribe found that they only needed the ‘mid-range’ NVIDIA GTX 1070 when adding more cards, which were half the price of the original GTX 980tis.

“The 1070s actually had a bit more memory, so we could push the envelope even further….and you saved a few grand,” notes Tiaan.

Having worked with the GPU-based renderer on previous productions, the team decided that the Redshift would suit Chocolate Tribe’s production methodology and requirements well at this level of production. Integration was seamless. When compared with alternative render solutions, the biased renderer output held its own comfortably.

“We were using Maya and immediately [Redshift] felt right at home. It is all about workflow for us. We program our pipeline using Python and MEL; and it was easy to accommodate Redshift,” explains Tiaan.

While Chocolate Tribe has used the Redshift plugin with Houdini, the team didn’t need it for Robot & Scarecrow. Tiaan singled out an easy way artists can switch between applications that use Redshift without the need to buy additional, application-specific plugins:

“That’s the amazing thing we love about [Redshift]; I could use my same license and jump to another platform. I didn’t have any licensing issues. It gives you the ability to explore other platforms without costing you double.”

TIGHT INTEGRATION

Redshift’s ability to integrate into a visual effects pipeline was also critical when it came to the final look of Robot & Scarecrow. Allegorithmic’s Substance Painter was used to create the textures. “The workflow between Substance Painter and Redshift was mind-blowing! After you had tested your shaders with the preview in Substance Painter, you would get exactly the same result [in Redshift] by just hooking up the textures properly,” says Tiaan.

Chocolate Tribe was able to utilise every part of its creativity when designing shaders for Robot & Scarecrow as Tiaan explains: “We had 4K textures on multiple outputs, normal maps, displacement maps - whatever you needed. On the Robot alone, she had 800+ pieces of geometry. We were concerned at render time that Redshift may fall over with all the textures, and it never happened.”

Rob agrees: “We never down-resolved our textures. We had 8K and 4K textures, we were throwing 1000s of textures at Redshift…I actually still don’t understand what Redshift was doing. It just handled it, I couldn’t believe it!”

Even when the shots were close-ups of Robot’s face, which consisted of a dynamic facial screen driven by a sub-surface scattering shader, render times were only slightly affected. “Normally if you go extremely close with sub-surface scattering on the face, you would expect to jump into greater render times. But it never really went beyond ten minutes a frame,” says Tiaan.

Although Scarecrow’s render times were much quicker than Robot’s, there was a large amount of texture-based displacement in the model. According to Tiaan, Redshift’s displacement tools were up to the task, especially the global parameter for displacement settings: “The simple thing of just selecting your geometry and controlling all of your displacement within one node. It’s such a timesaver.”

REAL-TIME ADJUSTMENTS

When it came to final render, Tiaan programmed a solution within Maya and Redshift to adapt the render samples needed per shot.

“We programmed our default preset to a base level. On a close-up shot, if we needed more samples we would turn it up. Off the bat, 80% of the time, our default preset held up,” he says.

“This was with global illumination, depth of field and motion blur,” adds Rob.

“That was a huge thing for us,” Tiaan explains. “Working with rendering you often get stuck with doing motion blur in post, and it’s horrible. Same thing with depth of field. We could tweak all of this [using Redshift] in real time in our camera view. Doing everything on the fly was just so much fun.”

This approach meant that Chocolate Tribe minimised the amount of passes it required when it came to compositing. “It was five passes max. We tried to do everything straight in the beauty. The main reason for this is that the final render just looks better when you do it all for real,” says Rob.

TESTING AND EXPERIMENTATION


At every one of the weekly production Skype calls, Chocolate Tribe had delivered a new edit with at least ten revised shots, which went up to more than fifty shots as production ramped up.

“We would continually keep them in the loop; it really helps to keep the client’s confidence levels high, with clear communication as they are seeing progress,” says Rob.

Tiaan also noted that as the pipeline got more streamlined towards the end of the production, Chocolate Tribe’s technical capability really came into its own: “We could start with a clean plate, with a final track, pulling in the rigs, caching them out and auto-assigning the shaders and light rigs. This is a whole process that we have automated. Literally from nothing to something, you could get there in ten minutes, kick a render off and see where you are at. This quick turn-around of shots allowed us to get a quick preview of multitude of shots in hours, or even minutes.”

When Kibwe Tavares visited Chocolate Tribe’s offices in Johannesburg, he was amazed at the speed that Chocolate Tribe was able to iterate through shots. Redshift was naturally a big part of this. “He was knocking doors down going, ‘Where is the render farm that you are hiding?’,” laughs Tiaan.

“I don’t think Redshift realise what a ‘shift’ they have created in the industry. They have redefined how the rendering process and pipeline can work,” says Rob. “Redshift has opened up a world of creativity, experimentation and artistic finessing.”

Chocolate Tribe chose their name to relate the fact that they are a community of dedicated and passionate creatives of all walks of life with a proud African vibe. This pride embodies the work that they have created for Robot & Scarecrow, not just for its artistry and technical achievement, but also for the fact that it has proven that the South African visual effects industry can facilitate the best directors and production companies anywhere on the planet.

Robot & Scarecrow is available to watch now, via Vero and Nowness.

To find out more about Chocolate tribe visit www.chocolatetribe.co.za and follow @ChocolateTribe on Facebook, Twitter and LinkedIn.