Animatrik Looks in New Directions for Performance Capture

Fire Fight

Animatrik helped MPC finish one of their sequences depicting intense combat between insurgents and army rangers, involving heavy fire fights in which we see characters shooting at each other. After looking at the main unit footage in post, the production felt the scene needed more soldiers and more action to deliver their story effectively.

What Bruno finds interesting about the ‘American Sniper’ project is that MPC decided on motion capture as their approach. “When we look at our business objectively, what we can deliver to a VFX company in every situation is a high-level starting point for animation,” he said. “It means their team does not have to animate from scratch. They have the base realism of the fight moves – or any other kind of performance – and from there they can move on to more creative work, while every motion can be based on reality.

“It is an inexpensive way to reduce the animation man-hours, whether it is for post-vis or another scenario. Furthermore, no production wants the audience to be noticing or thinking about mocap, or CG, or animation, when they see the movie. High quality motion capture makes CG invisible.” Motion data is valuable information for speeding up and improving the quality of keyframe animation, or for understanding better how a character should move.

In the Studio

Because the shoot had wrapped and the whole project had moved into the post production and visual effects stages, Animatrik took a post-viz approach to the job. Their task was to capture the performances of the required moves and retarget the captured data onto MPC’s 3D digital doubles, ready for delivery and compositing into the sequence’s plates.

Using motions captured by an experienced crew gave MPC a chance to achieve a range of specific, lifelike motions for this sequence. Working with MPC’s animation director, Animatrik carried out the project in one of their volumes in Vancouver measuring 40ft x 60ft, capturing the moves of three stunt actors at a time. This volume contains a fixed installation of 56 Vicon T160 and MX40 cameras mounted in an array on a truss. Each actor wore 58 tracking markers.

“Part of our service is building out the physical environment in the plates to exact measurements and detail," Brett said. "For this movie, we built army trucks and props to the exact proportions of the ones in the film so that our actors could ride up, hop out and begin acting out fight moves – interacting with the set just like the live action actors in the plate.”

For real-time review, the actors were watching themselves performing on large flat screens positioned around the volume, seeing their actions not on the stage but placed into the digital context of the footage. This way, everyone – MPC’s animation team, Animatrik’s crew and the cast - saw immediately whether or not the performances are turning out as required.

Vicon Blade software was used for the initial actor solve, turning the captured positional data into rotational data that matches the actor’s size and shape, followed by Autodesk Motion Builder for the real-time retargeting work that maps the solved motion to the CG models. MPC then received a final solve done in Animatrik’s proprietary solving system, developed to avoid various solving challenges. Bruno said, “Almost all commercially available solvers rely on some kind of IK/FK switching, for instance, which is susceptible to errors such as markers moving on the suit. The work we do circumvents these pitfalls.”

Literal Representation

Brett said, “Although a precise match between our set pieces and the live action set was essential, otherwise this wasn’t an especially challenging project for us. Given the amount of work we do for video games companies, capturing moves of soldiers shooting at each other wasn’t new territory. Also, because we were capturing motions for photoreal digital doubles, the goal was to supply the most realistic, literal representation of each actor’s moves possible, without deviation or interpretation. Normally we might be working from previs or an animatic, but for post-vis like this, the actions MPC wanted were precise, so it became a technical job for us.”

Brett and Bruno explained some of the reasons why motion capture has become a useful option for scenarios like ‘American Sniper’. In this case, the footage shot for the scene wasn’t reading correctly and was inconsistent with the story, but in other situations, adding mocap animations in post can improve the realism of shots using animated CG, or accommodate a story change. “Once a movie has gone into visual effects, story changes and scene augmentation may only be feasible with high quality CG animation,” said Bruno. Specific moves for a production may also be captured and placed into a library.

Animatrik offers this kind of turnkey capture studio session as a straightforward professional service that worked well for MPC on this film. The stage, camera set-up, technicians and facility services are all in place - MPC and the cast could walk in, have everything ready for the shoot within a few minutes and afterwards walk out with the motions solved and animation re-targeted.

New Options

But in other situations when a project is still in production or pre-production, Animatrik can be very flexible. For example, if the talent can’t come to the studio in Vancouver, Animatrik can bring their kit to the talent. The company is now working on new options for production, including ways to work in unfavourable lighting, in much larger volumes and to capture performances outdoors.