Prelighting

Pre-lighting is a technique used in computer graphics and visual effects to simulate the way light interacts with objects in a scene. It involves pre-calculating the lighting information for static parts of a scene before rendering the final animation or image. This is particularly useful for environments or objects that do not move.

The process typically involves casting rays from light sources into the scene and determining how these rays illuminate surfaces. This information, often stored as textures or data arrays, is then applied to the 3D models during the rendering phase. This can significantly speed up rendering times, especially for complex scenes with many light sources or intricate geometry, as the computationally intensive lighting calculations are performed only once.

Pre-lighting can encompass various lighting techniques, including ambient occlusion, global illumination, and shadow casting. Ambient occlusion, for instance, simulates how much ambient light is blocked by nearby geometry, creating soft shadows in crevices and corners. Global illumination aims to capture the bounced light that occurs in real-world environments, leading to more realistic and softer lighting.

While pre-lighting is efficient for static elements, it is not suitable for dynamic scenes where objects or lights are constantly moving. In such cases, real-time lighting techniques or on-demand calculations are necessary. However, for backgrounds, architectural visualizations, or game environments with fixed layouts, pre-lighting remains a valuable optimization tool. The quality and detail of the pre-calculated lighting directly impact the final visual fidelity of the rendered output.