Re: Experimental additions I want feedback for...

[ajchung]

> This required that every object be given a function to return a random
> point on the surface (easier than a 2d-3d mapping), with a default
> provided at the 'center' of the object.  One problem arising from
> adding the area light sources is that a HUGE number of samples must be
> taken for each pixel to get a decent image.

How is the ability to select a random point on an arbitrary surface
useful for area lights? Wouldn't the probability distribution depend
on the location and orientation of the receiving surface? Thus, one
should really be selecting a random direction spawned from the
receiver, possibly weighted by the BRDF and distribution of the
incoming radiance.

Consider a spherical luminaire: If one selects a uniformly random
point over its surface from which to cast rays to a receiving surface,
there will be a clear bias towards the silhouette edges of the
sphere. This is true for most regularly shaped luminaires.

Problems are worse for an object that can self occlude -- how does one
measure the fraction of light reaching the receiver in that case? Does
a very bumpy light source illuminate its environment any less than a
smooth one of the same size and intensity?


Adrian