Confessions of a Roto Artist: Three Rules For Better Mattes

*Confessions of a Roto Artist: Three Rules For Better Mattes
by Scott Stewart

As a professional roto artist on feature films, my single greatest concern is consistency. Do my mattes keep a consistent look over the course of the shot or do their edges chatter? These questions rank right up there with, “Is there absolute good in the Universe?” and “Why is dry-cleaning so expensive?”

Consistency is important because our eyes are immediately drawn to elements of a shot that don’t move in ways we’d expect them to. They stand out as somehow unnatural. For the roto artist, it’s not nearly as important to create mattes that articulate every nook and cranny of an element, as is it is for those mattes to move and change in a naturalistic and consistent way. The biggest giveaway that an element has been composited into a shot is if you can see its edges chatter. Our goal is to create mattes that don’t distract the eye and that means keeping things consistent.

Over time, I’ve picked up a number of techniques to aid me in my quest for consistency. Most of them can be boiled down to three basic rules that if you stick to religiously, will help your work stand up to even the most scrutinizing eyes, namely, your audience’s.

  • Think Like an Animator (Keyframe)
  • Use as Few Points as Possible, Then Try Not To Move Them Individually.
  • Use Multiple Shapes

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