Mathematic Goes Ape with Arnold on Coldplay’s Adventure of a Lifetime
The new Coldplay music video “Adventure of a Lifetime” was a truly transformational experience for the band – they performed the song in the digital bodies of chimpanzees. The illusion for the short film was achieved through the artistry of Andy Serkis-co-founded mocap studio/production company The Imaginarium and Paris-based VFX, animation and motion design studio Mathematic. We talked to Mathematic’s Animation Supervisor and Pipeline TD Sébastien Eballard, and VFX Supervisor Julien Lambert about the particulars of lighting and rendering with Arnold on the project. See a making-of here.
How did you approach lighting and shading on this project?
Given the project’s tight timeframe, we approached it like a TV show. We had to evolve lighting throughout the film, so we prepared every asset based on a basic light set with a premade animation that we could offset to match the shot. We tried to reduce the lighting tweaks for each shot to a minimum and shaders were practically untouched in the final scenes.
Why did you opt to render with Arnold?
Overall, we like Arnold because it is simple and efficient. We tend to use it when there’s a lot of fur, subsurface scattering and displacement involved. We have been working on furry characters for years, and in the past few it has become easier to handle lots and lots of hairs – several million. Arnold works perfectly with these huge amounts and was ideal for the Coldplay project. The enhanced compatibility of stand-in file format and VDB also really helped us on this project. We used Houdini to generate fog, collision simulation and ground scatter – leaves and branches, and passed them to MtoA (Maya to Arnold plug-in) for rendering using VDB and stand-ins.
How did using Arnold stand-ins help?
When we thought about how we would do the forest, the biggest challenge we had to overcome was the weight that it would have in the final rendering scene, without proxies even the translation time would have been enormous. So we proceeded to use Arnold stand-ins for each asset / leaves, branches, trunk, etc. In fact our final scenes contained nearly only stand-in bounding boxes except the characters which were sourced from Alembic files.
Beyond that, Arnold helps us tighten project timeframes overall. It is easy to set up and really powerful at the same time. The module deployment is really enjoyable. And being able to override the samples of the whole scene with a few knobs is a real plus.
What was your hair/fur rendering pipeline here?
We used a fur scene where the fur was planted on a referenced model. The published fur scene was then referenced in the lookdev so they could be worked on in parallel. We used the Shave and a Haircut plug-in to generate the hair models and overwrote the default shave shader with an alHair. We would have liked to export the fur as ASS file sequences but the server space it would have consumed would have been just too much. So we chose to generate the fur models at renderTime.
What shaders did you use?
We used mainly the alShaders, alSurface and alHair.
What were the render times, on what machines?
The average render time was four hours per frame. I think our most complex shot took about 80 GB of RAM, so we had to split the furry characters in two passes (of about 10 characters each). We had about 100 machines with specs: dual Xeon E2630v3 @ 2.4GHz (32 threads) with 8x8 GB (64 GB) of DDR4-2133 ECC RAM.
The music video/short film for “Adventure of a Lifetime” released 27 November. It is a single from Coldplay’s seventh studio album “A Headful of Dreams,” released 4 December.