Layer-by-layer assembly of image elements in post — integrating greenscreen footage, 3D assets, effects, and color into final plates. Happens in the VFX suite, not on set.
You're sitting at the edit suite, facing a layer from the green screen shoot — the actor in front of a green background, lit from the front, with no micro-movements in the camera. Next to it are three other layers: a 3D environment from the 3D department, particle effects from Houdini, and a correction layer for color grading. You need to bring all of this together in a controlled, non-destructive order — that's digital compositing. It's not editing itself, but the layer work after the shoot, where individual, visually separate image layers are overlaid, transformed, and color-matched in a defined hierarchy.
In the studio, you work with specialized software — Nuke, After Effects, Fusion — where each layer retains its own control. You isolate the green screen plate (keying), scale it perspectively to match the 3D camera motion, place the CGI environment underneath, the light effects on top, and then render everything together. The crucial point: each layer remains editable, up to the final render. The director wants the color warmer? No need to reshoot — adjust the color layer. The green screen keying is too harsh? Adjust the feathering without restacking the layers.
This is fundamentally different from on-set work. The VFX supervisor has already considered during the shoot: Which backgrounds will be added later? Where are tracking markers needed for 3D reconstruction? How intense does the lighting need to be for the finished element to look believable? In compositing itself, this is then brought together spatially and chromatically coherent.
The order is ritualized: Keying → Roto/Masking → 3D Integration → Particle/Effects Layer → Color Correction → Output. A single shot can have a hundred nodes in your Nuke script. And if a new VFX plate comes in or the client says the scene needs to be five frames longer — the entire layer structure must scale. That's why professional compositors work modularly, organize their nodes into groups, write expression helpers, and document their logic. In the end, you export a "plate" — the final, flat image, ready for DCP or broadcast.