Neil Gaiman’s bestselling, Hugo Award winning, epic novel American Gods has entranced readers across the globe with its blend of classic American road trip intertwined with supernatural folklore, and now it’s the turn of Canadian animation studio, Tendril, to entrance us with its short five-minute opening sequence for the American Gods series.

In the fifth episode, which was directed by Vincenzo Natali, the ‘Coming to America’ animated sequence tells the tale of the holy woman, Atsula, and her relationship with her God, Nunyunnini, as her tribe arrive on the new continent after being led across the land bridge from Asia.

With a background in animation, Vincenzo chose to work with the design-driven studio Tendril to create a striking, character-based story which relied on a stylised design for the main protagonists with naturalistic environments.

Tendril was brought on board in June 2016 during pre-production which enabled the concept and development teams to collaborate on the overall design process. This time also allowed the studio to test potential rendering solutions before production ramped up in September for a December delivery.

While Tendril had been using Redshift for design pitches - where the speed of delivering styleframes in five minutes had been a boon - the team was unsure about using a GPU-based solution for the detailed landscape environments that were a key component of Coming to America.

Tendril’s lighting and texture artists, Christian Hecht and Alex Veaux, worked on the style frame scene that was used to test Redshift. “It was quite a complex scene right off the bat! It was a full-on forest with ground cover, displacement on the bark, full volumetrics. Everything basically,” says Christian. “I was like, ‘GPU? I’m not sure!’”

Christian took some assets and quickly put together a forest style frame [in Redshift] and we were like, ‘I think it’s going to work!’” adds Alex.

While speed is a common reason that many artists use GPU rendering, Redshift was chosen for Coming to America as it could combine speed with reliable handling of the large datasets that the creative team would generate.

“Because Redshift has a very clean and stable implementation in Maya, it was much more reliable than any of the other render engines that we had used,” Alex explains.

EASY MATTES AND TILING

Due to the highly stylised nature of Coming to America, even though Redshift’s interactive preview allowed the artists to quickly see the scene, compositing was still a large factor. “It was probably one of the heaviest comp projects that we had done,” explains Alex. “Tons of AOVs and mattes. The good thing is that it was easy to set up.” Mattes especially had been difficult to create in Tendril’s CPU-based rendering software. “It was a nice surprise [with Redshift] - simple AOVs.”

The texture detail of the stylised animation is a standout feature of Tendril’s work. The characters had up to 90GB of textures each, spread over 6 UDIMS for each part of the model, including all of the authentically detailed clothing and props.

“Redshift did a really great job of tiling the textures,” adds Alex. “With previous renderers of course you have that, but it is not really tightly integrated. So it was great to see this in Redshift.”

WHEN THE CLOUD IS NOT ENOUGH

As the project schedule was tight, Tendril had to improvise a GPU-hardware solution.

“We tried using cloud-based GPU rendering, but the scenes were just way too big to consider a cloud solution. So it had to be in-house with workstations managed by Deadline render manager,” says Chris Bahry, creative director at Tendril.

Tendril set about filling as many workstations as they could with dual GPUs. “We scaled up from just having a few workstations with this spec to outfitting 18 workstations,” says Chris. Most of the workstations were running dual NVIDIA GTX 980tis, with a few running NVIDIA Titans for good measure.

“I had a Titan in my box with one 980ti,” Alex explains. “It was great, as I could see if we were going out of core [with the GPU memory] or not. It was a great benchmark. I found it very useful to have one [card] that is a little bit bigger, so that I could have some breathing room if needed.”

ENHANCED QUALITY AND CAPABILITIES

At the outset, Tendril had calculated that an hour per frame was the acceptable time needed for the show. “The Bison god was easily an hour and half,” comments Alex. This was offset by a lot of the character closeups, which took only 15-20 minutes per frame.

Tendril’s previous frame time on shows using a CPU-based render solution had also been around an hour per frame, but when comparing the output, Alex noticed that there was a marked difference with rendering in Redshift: “These scenes were fifty times bigger than anything we had done before with our previous render solution. Even though the render time was the same, the density and quality of the frame was so much more… We had never done hair before, or direct volume rendering with the beauty [pass].”

Another benefit above CPU-based rendering was the ability to easily add effects. “We had never done in-camera depth of field before either, as it was just too slow. We always did depth in post. In this, it was all in camera. That’s huge!” says Alex.

HELP AT HAND

Now that there has been time to reflect on the process for Coming to America. Tendril has invested in a dedicated GPU farm and is moving forward with Redshift on other projects.

Tendril kept Redshift’s support team on its toes, and was pleased with the fast responses and fixes that were delivered. “The guys were submitting bug reports and getting fixes during the project,” says Chris. “In a matter of days you would get stuff fixed, so that was really nice; with a really active forum,” says Christian.

“[The Redshift forum] has become the best Maya forum!” jokes Alex. “Everyone on there is pretty talented”.

READY AND ROBUST

The GPU renderer managed the resource-rich project with no problems: “If we can create an animation like that [in Redshift]. It speaks to how robust [Redshift] is,” says Christian, reflecting on how Redshift performed with the heavy datasets. This robustness did not just rely on the proven implementation of Redshift within Maya; many of the effects, such as the snow, smoke, fire and embers, were done using Houdini.

Using the alpha of the Redshift Houdini plugin, the team at Tendril rendered out the sims directly within Houdini. This saved time on production as it meant there was no need to translate the Houdini files into Maya.

“The very last shot is a Redshift alpha in Houdini; the one with the snow blowing. Because it was totally isolated, we were able to say, ‘Alright, let’s do it all in Houdini’,” explains Alex.

Redshift had enabled Tendril to create the dark and brooding Coming to America animation within the production schedule, with minimal creative or technical compromises. This was noticed by the director Vincenzo Natali when he arrived for a review session. Molly Willows, Tendril’s director of communication, remembers his comment: “Vincenzo said, ‘I couldn’t believe it, I came in to check on the progress and everything was rendered!”

American Gods is available to watch now on STARZ in the US and with various broadcasters throughout the world.