CORVALLIS, OR — Previs house Nvizage used OptiTrack’s Insight VCS to help visualize six major sequences and over 320 shots featured in Snow White and the Huntsman. By using motion capture to track the camera’s physical position, Nvizage and key crew members like DP Greig Fraser could visualize how live action and CG elements interacted with each other in realtime. This allowed the team to flesh out shot and lens ideas before principal production set anything in stone.
As the scope of the shot assignments changed from extreme wide shots of battlefields to close-ups of pivotal character transformations, the Insight VCS’s ability to validate production strategies became increasingly more valuable. For example, when trying to evoke the cavernous look established by the concept art for Ravenna’s Throne Room, Fraser used the VCS’s realtime display of the CG environment to assess how different lenses would paint the room. He found his match in a wide angle.
Since the system’s motion capture data can be mapped to any type of CG camera in Autodesk MotionBuilder, achieving the look of a handheld, car or heli-mounted unit was also easily attainable. Nvizage used this capability to previs a variety of small and large- scale shots. The VCS’s software plug-in and mappable controllers also allowed the theam to adjust camera speed while they were in their virtual environment, as well as automatically smooth out any accidental bumps and jolts that came with the rough terrain. Streamed shots were ported into MotionBuilder, facilitating instant takes that could be screened or carried into Maya for further animation and rendering.
During the film’s Troll Bridge sequence, Nvizage added OptiTrack’s body mocap system to the mix to record performance footage of VFX supervisor Cedric Nicolas. Incorporated into the sequence as a supplement to the production’s pre-existing animation, his troll-like gestures provided the realistic movement the scene had been lacking. Other collateral gained from the shoot, like step diagrams, hand impact points, and spatial measurements that revealed the distance between camera and actor could be used by the SFX team as detailed reference pieces for their design work.