It might be the ultimate VFX brief - show a bunch of bikes riding with no riders. That was the challenge faced by Alter Ego and visual effects supervisor Andres Kirejew for a new Cycling Canada spot in which a range of bikes head into the Canadian wild - sans their riders. We find out from Kirejew how a combination of live action, paint and roto, mocap, CG bikes and crowd work in Golaem made the spot possible.

The brief

The spot, called Hop On, was directed by Mark Zibert of Sons and Daughters for agency Innocean Worldwide Canada. The idea presented to Alter Ego, says Kirejew, was to show bikes without riders but still sell the weight and animation that different kinds of bikes exhibit. “Initially we thought it might be a huge paint and roto exercise,” recalls Kirejew, “but when we started talking about locations and where we’d have to go, I realized we’d have to look at CG more. And then we also needed to do pelotons!”


Original plate.
Original plate.
CG bike.
CG bike.
Final shot.
Final shot.
Brainstorming

A number of technical methods were considered to realize the vision for the spot. One was to fit the bikes somehow with an offset rig or even puppeteer them through shots. However, the remote locations at which plates would be shot prevented that possibility. Consideration was also given to re-creating shots in a studio. “But it just seemed like we were trying to over-complicate things,” relates Kirejew. “Mark Zibert, our Director/DP, has a specific shooting style - he really likes to be free and get the angles he wants. I didn’t want to be the guy chasing him down saying, ‘No, no, no.’”

The ultimate solution, as noted, was a mix of methods. But Alter Ego did set about a few early tests, including one involving motion capture and object tracking. “We put a bunch of trackers on a bike and put it on a roller to see if we could capture animation sequences,” explains Kirejew. “That didn’t really work very well. Then there was an iPhone app called CameraMan that connects into Maya. We put one phone on the front to capture the rotation and one phone on the back to capture the body and then that would send keyframe data into Maya. In the end we weren’t able to use that animation for the peloton, we ended up building libraries of keyframe animation."

Watch a breakdown.

Live action

Further tests resulted in the mixed approach - some bikes would feature real riders painted out, and bike parts and backgrounds tracked and painted back in, some bikes would be CG, some would be ‘ghost ridden’ through the shots and some were achieved with a crowd solution through Golaem. The basis for all these, of course, was a live action shoot where a ton of real riding and bike footage could be filmed - for final shots and for reference.

The shoot began in Vancouver, captured mostly on the RED EPIC and a MOVI rig, as well as some GoPro shots. “The whole idea was that we needed to get real live animation reference for the animators,” says Kirejew. “So what we decided to do was get two passes for every take. The first was the performance with the riders wearing one-color suits. Then we would try and do a clean take - no motion control, just a live re-creation of the pass knowing full well that if we ended up doing a CG pass we could camera track it, re-create some of the terrain and use that to put the bike in.”

Watch a breakdown.

While on location, Kirejew shot HDRs and stills of every environment and reference stills of the bike used - “literally gigs and gigs of of every single bike - pedals, gears, everything.” Shots were also matched up with a mood piece edit that had been cut by Mark Paiva of Saints Editorial. Interestingly, the production had to learn quickly to re-frame the bikes during shooting. “Naturally you’re shooting with a rider so you frame to capture them,” notes Kirejew. “We’d be shooting a little too high and have to tilt down a bit.”

Building, and re-building, bikes

With the live action plates acquired, Alter Ego then set about creating camera tracks - a step that initially proved quite challenging. “We tried traditional tracks,” notes Kirejew, “but we couldn’t generate the terrain and we didn’t have enough time to re-create and model everything. So one of our compositors said let’s try it in NUKE. We knew the point cloud generator was an easier way - if you get a good enough solve and have enough points - it will help you build the terrain. So that was pretty much our solve for 99 per cent of the shots where we used CG. We’d camera track in NUKE, generate a point cloud as dense as we could and then literally build whatever terrain or topology we needed and then that was exported out - the camera, the undistorted plate and everything we needed - to Maya.”

Watch a breakdown.

The next step was animation for the CG bikes. These had been built in Maya based off of the extensive reference photography, then rendered in V-Ray. Animation-wise, Alter Ego looked to a surprising tool for help. “We used an app that was fairly old called Craft Director,” says Kirejew. “You can put a video game rig into it and you remote control the bike. So it acts like a more organic way of controlling the bike. You have to just match up the rig to the model that you’ve built and then when all that snaps into place, you can literally move by keyboard with arrow keys. It would build into the suspension or animation so that would sometimes be one pass, and then fine-tuning the keyframes to give it more life.”

Then there were several shots in which a rider on a bike had been photographed in the live action plate. For these, Alter Ego embarked on significant paint and roto. “It was just grunt work for these shots - paint, track, paint, track,” says Kirejew. “We’d re-create the background and track that back. No magic science, just elbow-grease. We also had to remove the shadows of the bikers off the ground, which was a real challenge.”


Background bikes.
Background bikes.
Foreground bikes.
Foreground bikes.
Final shot.
Final shot.
Bike crowds

In addition to hero shots, a few scenes also required cycling pelotons with more than 100 bikes. Researching a crowd solution for those, while also watching a large amount of Tour de France footage, Alter Ego happened to catch a demo from Golaem Crowd in Toronto. The software, more traditionally used for human or animal figures, was not something Alter Ego had necessarily considered for multiple bikes. But, as it turned out, accomplished Golaem user (and fxphd.com professor) Gareth Stevenson had developed a bicycle rig for as yet unreleased film - and Golaem put Gareth in touch with Alter Ego.

Watch a breakdown.

Stevenson’s rig dealt with the specifics of wheel traction and ground contact. “We got in contact with Gareth,” relates Kirejew, “and he helped us out making sure the rig worked. The way we built the textures was very modular - we could dial up more red bikes, green bikes - we just did turntables of the different textures and showed the agency and client to pick. We honed that to a specific set, but in that big peloton shot there’s ten different colors and textures and when you mix and match and change the seat heights and make things look a little more random - then it was just changing the animation cycles it would call up - it ended up working out really well.”

End game

For Kirejew, the benefits of multiple approaches - all based on real reference - were obvious. “Doing it this way meant there were no questions about, is there enough weight on the bike, is the performance being captured? Does it look real? For the CG shots, we had to obviously pay more attention to the tires, the shocks for suspension, but it was all grounded in realism otherwise it would give the gag away.”


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