This Inventor program reads distributions in from a scene file, then it creates an isosurface and applies the emittance distribution to the surface. The surface isovalue is controllable interactively through a dragger. The isosurface is then point-sampled from a sphere and the sample is rendered on the sphere in an interactive manner, with cylinders to visualize the rays used to make the samples.
To write this program I used code form several people.
Marching Cubes code,
Fast Primitive code
Dr. David C. Banks Inventor skeleton
Tomas Moller Ray-triangle intersection code