This is documentation for Mathematica 4, which was
based on an earlier version of the Wolfram Language.

SurfaceColor

SurfaceColor[dcol] is a three-dimensional graphics directive which specifies that the polygons which follow should act as diffuse reflectors of light with a color given by dcol.

SurfaceColor[dcol, scol] specifies that a specular reflection component should be included, with a color given by scol.

SurfaceColor[dcol, scol, n] specifies that the reflection should occur with specular exponent n.

SurfaceColor directives give surface properties which determine the effect of simulated illumination on polygons.

SurfaceColor directives can appear inside FaceForm directives.

If no SurfaceColor directive is given, polygons are assumed to be white diffuse reflectors of light, obeying Lambert's law of reflection, so that the intensity of reflected light is times the intensity of incident light, where is the angle between the direction of the incident light and the polygon normal. When , there is no reflected light.

SurfaceColor[GrayLevel[a]] specifies that polygons should act as diffuse reflectors, but with albedo a. The intensity of reflected light is therefore a times the intensity of the incident light, multiplied by , and is of the same color.

SurfaceColor[RGBColor[r, g, b]] specifies that the red, green and blue components of the reflected light should be respectively r, g and b times those of the incident light, multiplied by .

The second element in SurfaceColor[dcol, scol] specifies a specular reflection component. scol must be a GrayLevel, Hue or RGBColor specification. The color components of scol give the fractions of each color component in the incident intensity which are reflected in a specular way by the surface.

The parameter n gives the specular exponent. The intensity of specularly reflected light at angle from the mirror-reflection direction falls off like as increases. It is zero when .

For real materials, n is typically between about 1 and a few hundred. With a coarse polygonal mesh, however, values of n below 10 are usually most appropriate. The default value for n is 1.

Mathematica implements a version of the Phong lighting model, in which the intensity of reflected light is given schematically by .

The intensity of light from diffuse and specular reflection is added linearly for each color component. The final color shown for a particular polygon is the sum of contributions from each light source, and from ambient light.

See The Mathematica Book: Section 2.9.12.