This material is a constant shader and is not affected by lighting. It is the value of the cosine of the angle between the camera and the surface normal. When the surface normal and the camera line up, the incidence vector is parallel to the surface normal and the returned color is white. As the normal follows the curve of the object’s surface, the normals falls away from the camera. The return value goes to black, when the surface normal is perpendicular to the camera ray/incidence vector. It can be used to make "glowing" spheres to give the appearance of a light bulb; or to soften the edges of dust or cloud objects. Tubes can be used for light sabers or other "laser" beams. Cones can be use as the light cast by street light in the fog.
Parameters
Glow Color
This parameter is used to set glow color.
Tint with Point Color
If this box is checked, the point color, (Cd), if defined, is multiplied
with the Glow Color. Defaults to on.
Use Point Alpha
If set, the Alpha attributes will be multiplied into the final Opacity. If no Alpha Attribute exists, Opacity is unaffected.
Glow Ramp Rate
This is an exponent which effects how quickly the falloff goes to 0. Higher number make the center stronger and the edges more transparent.
Invert
If the "glow" is inverted, white on the edges and black in the center, it can be used to simulate a Fresnel effect by multiplying it with an environment map color.
Enable Emission
When in emissive mode, no alpha is output. This causes the glow to add to the underlying colors rather than replacing them, giving the effect that it is a light source.
Emission
When in emissive mode, scales the glow color that is added to the scene.
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