Rotoscoping

Rotoscoping is the technique of manually tracing or masking elements within a frame, frame by frame, used in animation either to extract a clean cutout of a subject for compositing or to draw an animated character traced over live-action reference.

There are two distinct uses of the same word. The first, the production VFX use, is about extracting elements from footage, typically to remove a subject from one background and place it over another, where chromakey is not available or not clean enough. The second, the older animation use, is about drawing animated characters by tracing over live-action reference, a technique pioneered by Max Fleischer in the 1910s and used in everything from early Disney to A Scanner Darkly.

In our work, the production VFX use is more common. A subject filmed on location needs to be extracted for compositing into an animated world; a chromakey was not possible; a rotoscope artist traces the subject's outline frame by frame. The work is meticulous and time-consuming. AI-driven roto tools (segmentation models like SAM, AI keyers in modern compositing software) now handle much of this automatically, with human refinement for the tricky sections.

On work that combines live-action and animation, rotoscoping is part of the compositing toolset alongside chromakey, match move, and motion tracking. They each solve different parts of the same problem: getting a clean foreground element to sit cleanly inside an animated scene.

On hand-drawn projects like A Modern Fairytale, the older traced-over-reference use of rotoscoping informs the animator's eye for natural human movement, even when the final animation is not literally traced.