LightSources is an option for Graphics3D and related functions that specifies the properties of point light sources for simulated illumination.
The basic form is LightSources -> , , ... , where the are the specifications for each light source. Each has the form direction, color. The direction is specified as x, y, z, where the components are with respect to the final display area. The and are horizontal and vertical in the plane of the display; is orthogonal to the display. Positive is in front. Only the relative magnitude of the components is relevant; the overall normalization of the vector is ignored. The color can be specified by GrayLevel, Hue or RGBColor.
Simulated illumination determines the shading of polygons in three-dimensional pictures.
The shading of a particular polygon is computed as a sum of contributions from point light sources, plus a contribution from ambient light.
Surface properties of polygons are specified by SurfaceColor directives.
Light reflection properties assumed for polygons are described in the notes for SurfaceColor.