User Manual

Table Of Contents
Specular
The parameters in the Specular section describe the look of the specular highlight of the
surface. These values are evaluated in a different way for each illumination model.
Specular Color
Specular Color determines the color of light that reflects from a shiny surface. The more
specular a material is, the glossier it appears. Surfaces like plastics and glass tend to have white
specular highlights, whereas metallic surfaces like gold have specular highlights that inherit
their color from the material color. If a specular texture map is provided, then the value provided
here is multiplied by the color values from the texture.
Specular Intensity
Specular Intensity controls how strong the specular highlight is. If the specular intensity texture
is provided, then this value is multiplied by the Alpha value of the texture.
Spread U
Spread U controls the falloff of the specular highlight along the U-axis in the UV map of the
object. The smaller the value, the sharper the falloff, and the smoother and glossier the material
appears in this direction. If the Spread U texture is provided, then this value is multiplied by the
Alpha value of the texture.
Spread V
Spread V controls the falloff of the specular highlight along the V-axis in the UV map of the
object. The smaller the value, the sharper the falloff, and the smoother and glossier the material
appear in this direction. If the Spread V texture is provided, then this value is multiplied by the
Alpha value of the texture.
Transmittance
Transmittance controls the way light passes through a material. For example, a solid blue
sphere casts a black shadow, but one made of translucent blue plastic would cast a much lower
density blue shadow.
There is a separate Opacity option. Opacity determines how transparent the actual surface is
when it is rendered. Fusion allows adjusting both opacity and transmittance separately. At first,
this might be a bit counterintuitive to those who are unfamiliar with 3D software. It is possible to
have a surface that is fully opaque but transmits 100% of the light arriving upon it, effectively
making it a luminous/emissive surface.
Attenuation
Attenuation determines how much color is passed through the object. For an object to have
transmissive shadows, set the attenuation to (1, 1, 1), which means 100% of green, blue, and red
light passes through the object. Setting this color to RGB (1, 0, 0) means that the material
transmits 100% of the red arriving at the surface but none of the green or blue light. This can be
used to create “stained glass”-styled shadows.
Alpha Detail
When the Alpha Detail slider is set to 0, the Alpha channel of the object is ignored, and the
entire object casts a shadow. If it is set to 1, the Alpha channel determines what portions of the
object cast a shadow.
Chapter –82 3D Material Nodes 1791