Return to index
Return to index
####
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