When I was working on technology for Metastream, one of the things I was doing was trying to make good spheremaps.|
This utility is a rewrite of one piece of technology I did there, a "spherical blur." I've figured out how to make this thing run in real-time now, so I thought I'd post this slow noisy one.
This app is ugly because you have to run from the command line, but it will give you a nice graphical preview while it's rendering.
You can then mess with it in Photoshop, including using my Fresnel plugin to add edge highlights and make your own fake reflectance functions.
You can download the app here: SBlur [360kb] Here's some documentation (included in the zip.)
sblur: blurs a spheremap
Usage: inputfile.JPG diffusesamples specularsamples shininess
The input is a JPG, and output is a "max quality" JPG.
It needs three values as input.
Generally, you can start tweaking material parameters using low numbers of samples (<200 for each), and then just multiply by 10 for a final render.
Use many more specular samples than diffuse, since they're "weaker" and, as a result, noisier too. If you wanted, say, equal parts diffuse and specular, you might need 10x as many specular samples.
Weighting of specular vs. diffuse is not predictable (though it will make sense if you don't change shininess), but in general you have to do it visually.
All files will be written with their parameters in the filename, so you can remember the values.
Blur the jpg at low quality (50 diffuse samples), no specular:
Blur the jpg at medium quality, with specular coefficient 25:
Thanks to Ben Weiss for the "bryce.jpg" I've used as an example file.