Design Nomenclature / Light & Optics
Ambient light
Also called ambient term, ambient
This entry has not been translated yet and is shown in English.
In a renderer, a constant added to every shaded point regardless of direction, occlusion, or distance — a flat lift with no physical referent, invented to fake indirect light before global illumination was affordable. In a room, the same phrase means the real diffuse light arriving from every direction at once.
In practice
The two senses are unrelated and both are current. Renderer ambient is a cheat that flattens form; room ambient is real, directional in aggregate, and does not.
Not to be confused with
- Indirect lightLight reaching a point only after one or more reflections off other surfaces. It carries their colour, arrives from broad directions rather than from one, and fills form shadows — which is why a scene lit by direct light alone has shadows that go dead black.
- Global illuminationAny solution to light transport accounting for light that arrives after reflecting off other surfaces, not only direct from emitters. It is a category, not an algorithm — radiosity, photon mapping, path tracing, and irradiance caching all compute it, with different biases and different failure modes.
- HDRIA photographic capture of the whole sphere of incident radiance at a point, stored in floating point so the sun stays thousands of times brighter than the sky rather than clipping to white. Used as a source, it supplies direction, colour, softness, and reflection from a real location at once.