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NAME

ed - set the diffuse emittance for the current material

SYNOPSIS

ed epsilon_d

DESCRIPTION

Set the diffuse emittance for the current material to epsilon_d lumens per square meter using the current color to determine the spectral characteristics. Note that this is emittance rather than exitance, and therefore does not include reflected or transmitted light, which is a function of the other material settings and the illuminated environment.

The total lumen output of a convex emitting object is the radiating area of that object multiplied by its emittance. Therefore, one can compute the appropriate epsilon_d value for an emitter by dividing the total lumen output by the radiating area (in square meters).

The default emittance is zero.

EXAMPLE 

# A 100-watt incandescent bulb (1600 lumens) modeled as a sphere
m
	c
	cct 3000
	ed 87712
v cent =
	p 0 0 0
sph cent .0381

SEE ALSO

c, ir, m, rd, rs, sides, td, ts