When doing ray tracing, do we sample more rays when the radiance value is big? Or is it enough to encode radiance as some form of "brightness"?
This slide states that radiance is constant along a ray in a vacuum. Does that mean that the quadratic falloff from earlier (or falloff in general) does not exist in vacuum?
Given the ability to compute radiance in different directions at a given point, how do we translate that into a color?
In what situations would radiance not being constant along a ray be important?
Is there any situation where one has to account for non-constant radiance along a ray, or is the assumption of a vacuum usually appropriate?