luminaire_bias parameter

[tim.goransson6XTRC]

Hello, 

how does the luminaire_bias parameter work? its default value is 1.00e-06, which I think is 1 million. the documentation is a bit vague "Sets a distance offset for shadow rays to prevent a light becomes an occluder itself." 

in what situations would we want to change this value?

[Stephen.Blair · Accepted solution]

1e-6 is  0.000001

It's slightly shortening the shadow ray so that the shadow ray doesn't hit the light source itself.

Anything that a shadow ray hits will cast a shadow