This scene has relatively simple geometry, but demonstrates most of the features of our raytracer. The coins are modeled as cylinders, with bump maps on the front, back, and (in the case of the quarter and dime) sides. The dollar bill is a textured triangle mesh, with fractal heights. The image was rendered using distribution ray tracing to simulate penumbrae and glossy reflections.
To generate the bump maps, we scanned each coin on a color scanner, which had 3 separate lights for red, green, and blue. Thus the scanned color of the shiny coin surface varied with the surface normal. Since the red and green lights illuminated the surface from opposite sides, subtracting the red component from the green gave us the tilt of the surface at each point. By repeating the scan in two perpendicular directions, we acquired both components of the surface normal. If you're interested, the raw bumpmap data are here (2.7MB gzipped tar file).
Full-size pictures:
Gamma corrected
or
uncorrected
(Both are 800x800 JPEGs)
The model for the crystal consists of approximately 450 transparent, intersecting polyhedra. We use volume ray tracing to modulate the color and amount of light trasmitted through the crystal, according to a 3d rgba texture. For this modulation, we used a random turbulence function, and added dark splotches (yes, that's the technical term) by increasing opacity along random walks through the 3-d texture.
Original version:
Gamma corrected
or
uncorrected
New version (with brighter highlights):
Gamma corrected
or
uncorrected
(All are 600x600 JPEGs)
Movies of the crystal growing:
Big (100 frames, 400x400)
or
Small (50 frames, 200x200)
Movies of the full-grown crystal:
Big (41 frames, 400x400)
or
Small (21 frames, 200x200)
(All movies are non-Xing MPEGs, and are not gamma corrected. Uncompressed
movies are available upon request.)
