Reference:Average Pattern

Technically average is not a pattern type but it is listed here because the syntax is similar to other patterns. Typically a pattern type specifies how colors or normals are chosen from a pigment_map, texture_map, density_map, or normal_map , however average tells POV-Ray to average together all of the patterns you specify. Average was originally designed to be used in a normal statement with a normal_map as a method of specifying more than one normal pattern on the same surface. However average may be used in a pigment statement with a pigment_map or in a texture statement with a texture_map or media density with density_map to average colors too.

When used with pigments, the syntax is:

AVERAGED_PIGMENT:

pigment {
  pigment_map {
    PIGMENT_MAP_ENTRY...
    }
  }

PIGMENT_MAP_ENTRY:
[ [Weight] PIGMENT_BODY ]

Where Weight is an optional float value that defaults to 1.0 if not specified. This weight value is the relative weight applied to that pigment. Each PIGMENT_BODY is anything which can be inside a pigment{...} statement. The pigment keyword and {} braces need not be specified.

Note: The [] brackets are part of the actual PIGMENT_MAP_ENTRY. They are not notational symbols denoting optional parts. The brackets surround each entry in the pigment_map.

In previous versions there had to be from 2 to 256 entries in the map. A Change in version 3.8 has removed the upper restriction.

For example

pigment {
  average
  pigment_map {
    [1.0  Pigment_1]
    [2.0  Pigment_2]
    [0.5  Pigment_3]
    }
  }

All three pigments are evaluated. The weight values are multiplied by the resulting color. They are then divided by the total of the weights which, in this example is 3.5. When used with texture_map or density_map it works the same way.

When used with a normal_map in a normal statement, multiple copies of the original surface normal are created and are perturbed by each pattern. The perturbed normals are then weighted, added and normalized.

See the sections Pigment Maps and Pigment Lists, Normal Maps and Normal Lists, Texture Maps, and Density Maps and Density Lists for more information.