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Next: 1.9 Shadow Maps Up: 1. Functionality Previous: 1.7 Light Sources

# 1.8 Area Light Sources

The main purpose of area light sources is to generate more realistic lighting, resulting in soft shadows. This is achieved by using one of four primitives (rectangles, discs, spheres, and cylinders) as light sources with nonzero area. This means that a point on an object may be illuminated by only a part of a light source. Area light sources are based on similar principles as motion blurring, and, like motion blur, may reduce rendering speed.

Area light sources are specified in the `.mi` file by naming a primitive in a standard light definition. Any of the standard spot and point lights can be turned into an area light source. The orientation of the disc and rectangle primitives may be chosen independently of the light direction of spot and directional light sources. Any type of light shading function can be used.