A surface definition consists of a number of component keywords, each of which is usually followed by either a single number or a red-green-blue color triple. Each of the values in the color triple are normalized, with zero indicating zero intensity, and one indicating full intensity.
If any surface component is left unspecified, its value defaults to zero, with the exception of the index of refraction, which is assigned the default index of refraction (normally 1.0).
Surface descriptions are used in <#673#><#2338#>rayshade<#2338#><#673#> to compute the color of a ray
that strikes the surface at a point
If
A surface's ambient color is always applied to a ray. The color
applied is computed by multiplying the ambient color by the intensity
of the ambient light source.
Use the given <#680#>color<#680#> to approximate those surface-surface
interactions (e.g., diffuse interreflection) not modeled by the
ray tracing process.
The diffuse contribution from each non-shadowed light source at
Specifies the diffuse color.
Specifies the base color of specular reflections.
The intensity of specular highlights from light sources are
scaled by the specular color of the surface.
Controls the size of the specular highlight. The larger
the <#698#>exponent<#698#>, the smoother the apparent finish.
The intensity of specularly reflected rays will be proportional to
the specular color of the surface scaled by the reflectivity.
Specifies the specular reflectivity of the surface. If non-zero,
reflected rays will be spawned.
Specifies the specular transmissivity of the surface. If
non-zero,
transmitted (refracted) rays will be spawned.
Specifies the body color of the object. The body color
affects the color of rays that are transmitted through the
object.
The extinction coefficient is raised to a power equal to the distance
the transmitted ray travels through the object.
The overall intensity of specularly transmitted rays will be proportional to
this factor multiplied by the surface's body color
multiplied by the transparency of the object.
Specifies the extinction coefficient of the interior
of the object.
Specifies the index of refraction. The default value is equal
to the index of refraction of the atmosphere surrounding the eye.
If a light source illuminates a translucent surface from the side opposite
that from which a ray approaches, illumination computations are performed,
using the given color as the surface's diffuse color, and the given
exponent as the Phong highlight exponent. The resulting color is then
scaled by the surface's translucency.
Specifies the translucency, diffusely transmitted color,
and Phong exponent for transmitted specular highlights.