Rob Bredow Q & A

Rob Bredow is a senior CG supervisor at Sony Pictures Imageworks who recently completed work on The Polar Express. Within this section Rob answers my specific questions relating to the present difficulties and future possibilities of Motion Capture. Rob's work also includes lead effects animator on Stuart Little. You can view Robs full resume at his website linked here.

Do you feel the occasional misuse of motion capture has given it a bad name?

Motion capture driving realistic human performances is not a simple task. Often, motion capture is seen simply as a cost-savings method which can reduce or eliminate the need for animators--but for high end animation work with motion capture, experienced animators play a very important role. There are many subtle aspects of a performance which are not convenient to capture using motion capture (eye gaze direction, eyelids, tongue, etc) which need to be animated by hand to provide a convincing performance. Also, most of the time, the actor and the character do not match perfectly and there is an extensive and complicated translation process to map the actions and the expressions from the actor onto the virtual character which requires strong artistic and technical skills. Motion capture is a powerful tool but it is not the right tool for every type of work as well.

All these factors combine to contribute to motion capture that doesn't reach it's full potential and can lead to people thinking motion capture itself is flawed in some ways.

What have been your biggest Motion Capture issues or difficulties during the production of Polar Express?

I think most people would agree that the hardest part of working with motion capture is the action on the face and the eyes. It's a challenge to get accurate enough motion capture data to articulate the subtle performances of a face. Also, if the facial performance is slightly off, the final result can look obviously wrong--even to an untrained eye. Throughout the production of Polar Express, teams worked hard to improve the technology and the animation of the face and the eyes.

Where do you see a gap for new technologies relating to motion capture?

Facial mapping is an active area of research and there is still room for improvement there. It would also be ideal to have a motion capture system that did not rely on line-of-sight for capturing data (which would eliminate the time-consuming task of tracking the markers by hand).

Improved motion capture accuracy and larger capture volumes would also be convenient.

With Motion Blending, is this an issue that is still quite time consuming, or have automatic techniques eliminated the need to manually adjust the blending of motions?

The technical aspects of motion blending are fairly well addressed with techniques in modern software (Maya, MotionBuilder). Even with these tools, it still takes careful planning and a strong animator to make the blends feel right.

Finally can we expect more films utilizing the same technologies we saw in Polar Express?

Yes, but I'm not at liberty to discuss shows currently in production at Imageworks. There is a little information publically available if you take a look at the films listed in the "upcoming films" on Imagework's website here:

And then look those movies up on IMDB to find a few hints.

It should be noted that these responses are not representative of Rob Bredows employer Sony Imageworks.

Origins Marey Muybridge Fleischer Rob Bredow Q & A Debate Siggraph Panel CG Animation Pipeline Future Squash and Stretch Splines Experiment Summary Further Reading

(c) Shane Aherne 2005