This operator sends a ray starting at origin
P and in the direction
specified by the normalized vector
D. The resulting color, opacity and
alpha will be returned.
The Bias parameter is typically a small number used to prevent self-shading. The Max Contribution parameter is used to give the renderer an idea of how much the result of the Trace operator will contribute to the resulting pixel color, but has no effect on the results of the trace.
If the position (
P) input is not connected, the global variable by the
same name will be used instead.