UV Remap

The UV Remap operator distorts a layer using a second image — a UV map — that tells the operator, for every output pixel, which pixel of the source layer to sample. It is the same idea texture artists use in 3D software, lifted out into a real-time live-video pipeline. Anywhere you can render a UV pass from your DCC tool, you can use it to drive a remap inside Composer at full broadcast frame rate.

Typical uses include:

• Projecting live video onto a 3D-rendered surface (a virtual TV in a set, a curved billboard, the side of a CG vehicle) by exporting a UV pass from Blender, Maya, Houdini, Cinema 4D, etc.
• Wrapping live footage around virtual props or set pieces in a green-screen / extended-reality production.
• Applying lens-warp, screen-distortion, or barrel/pincushion correction effects via a hand-painted or rendered UV map.
• Building stylised mirror, kaleidoscope, ripple, or morph effects where every pixel is rerouted from somewhere else in the source.

How a UV map works

A UV map is just an image, but the colours don't represent colour — they represent coordinates:

• The red channel encodes the horizontal position (U) on the source layer to sample, from 0.0 (left edge) to 1.0 (right edge).
• The green channel encodes the vertical position (V), from 0.0 (top) to 1.0 (bottom).

When the operator processes each output pixel, it reads the matching pixel out of the UV map, decodes the red and green values into a (U, V) pair, then samples the source layer at that location. A flat, identity UV map (a smooth red-to-right, green-down gradient) re-renders the source untouched. Anything else twists, projects, repeats, or stretches the layer based on what the colours describe.

UV maps can be authored two ways:

• Rendered from 3D software — drop a UV pass on top of your geometry in Blender, Maya, Houdini, etc. and render it out. The pass already understands the surface, so the live video projects onto it correctly without any per-shot tweaking.
• Painted or generated procedurally — build distortion or effect maps by hand in any 2D tool, or generate them from a script when the effect doesn't need to follow real geometry.

Tip — use 16-bit PNGs

The operator supports both 8-bit and 16-bit UV maps. 16-bit PNG is strongly recommended for anything beyond simple distortions: 8-bit only has 256 levels per channel, which produces visible banding/stepping on slow gradients (think a curved object filling the frame at HD or 4K). 16-bit gives 65 536 levels and removes the stepping entirely.

Quick start

1. Render your UV pass from your 3D tool, save it as a 16-bit PNG, and place it somewhere accessible from Composer.
2. Add the UV Remap operator to the layer holding your video / image source.
3. Set UV Map Image to the PNG you just rendered.
4. The source layer is now projected through the UV map. Adjust Scale U / V and Offset U / V to nudge what part of the source ends up where on the rendered surface — useful for sliding video around inside a virtual screen without re-rendering the UV pass.

Tuning the result

• Tile mode — how the source behaves when the UV map references coordinates outside the layer. Clamp holds the edge pixel; Repeat tiles the layer endlessly; Mirror flips alternate tiles so seams disappear, which is handy when wrapping continuous surfaces.
• Filter mode — how Composer samples between source pixels. Bicubic (the default) gives the smoothest, highest-quality result on HD / 4K renders. Bilinear is the standard smooth fallback. Nearest keeps pixels crisp, which suits pixel-art looks and any case where you'd rather see hard pixels than soft interpolation.
• Background mode — what to show in pixels where the UV map has no valid coordinates (the off-surface region around your 3D object). Transparent is the right pick for compositing onto another scene. Original shows the unprocessed source. Color fills with a chosen solid colour for previews or stylised looks.

When to reach for it

UV Remap is the right operator when the distortion is content-aware — when the way pixels move depends on real geometry or a hand-authored map rather than a simple parametric formula. For straightforward zooms, rotations, or perspective tweaks the layer transform is usually enough. As soon as you need to project live video onto a virtual surface, wrap it around a curved object, or apply a custom warp that no built-in operator knows about, this is the tool.

UV Remap - Settings

UV Map

UV Map — load the UV coordinate image rendered from your 3D software.

UV Transform

UV Transform — scale and offset the source layer before it is sampled by the UV map.

Sampling

Sampling — how the source layer is sampled when looked up via the UV map.

Background

Background — what to show where the UV map has no valid coordinates (e.g. outside the rendered surface).

UV Options

UV Options — fix common UV-orientation differences between 3D packages.

Performance and Properties

Performance and Properties — status messages from the operator.

Inherits from: AbstractOperator, AbstractAudioMetering.

See also: UV Remap in Script Engine Objects.