Sang Yoon Lee's multiple scattering research
Sang Yoon Lee's multiple scattering research
Sang Yoon Lee, one of my grad students here at GWU, and I have been working on clouds, in collaboration with Nelson Max of Lawrence Livermore National Labs. Our goal is to combine realistic geometric models with a radiosity solution for the illumination. I've done the geometric models (with adaptive levl of detail), and Sang has reimplemented Nelson's scheme for anisotropic, high-albedo multiple scattering, and combined it with my model(s). The Holy Grail we seek is a back-lit cumulus cloud, replete with crepuscular rays (sunbeams). As you can see, we're within spittin' distance now...
A technical sketch submitted to SIGGRAPH 98.
Below is some of my earlier work that lead up to Sang's advanced images.
Low fractal dimension
Higher fractal dimension
The images above are tests of a little program I wrote that ray-marches a self-shadowing hypertexture with adaptive level of detail (of fractal dimensions ~2.3 and ~2.6). Holly is going to add a Monte Carlo radiosity solution to this model. But I was pleasantly surprised at how nice this no-scattering model looks by itself, so I thought I'd put it out here for all to see.
It took about 15 minutes to render at 512x410 on a 150 MHz R4400 Indy. These images were done so that Holly and I would have something new to show at SIGGRAPH 95...
For kicks, you might try to fuse the stereo pair below. Here at home, I can stick my nose right up to the screen, concentrate the gaze of each eye on a certain feature, and draw slowly back to get an in-focus stereo view. It'll only work, methinks, if the pair comes up on your screen with a separation about the same as that between your eyes. (Works at this resolution on my monitor!)
High transparency; low fractal dim.
Medium transparency
Mountain casting shadows into clouds
And another low-res stero pair. Not a particularly good one, but it does have some depth.
A stereo pair of the mountain and cloud
Stereo pair of a 3-D cloud.
