Bug on Notes of Thurston
by Jeffrey Brock and David Dumas
This ray-traced image shows approximately 18000 overlapping coplanar
solid glass spheres pictured in front of a page from the lecture notes
of William Thurston's 1978
Geometry and Topology of Three-Manifolds
. The intersection of
the spheres with the plane containing their centers is a domain of
discontinuity of a quasi-Fuchsian group of genus 2 created by a
shear-bend deformation of a Fuchsian group.
This image was created in January 2006 for a poster announcing the
and Dynamics in Surfaces and 3-Manifolds (held at Brown
University, May 3-6, 2007).
For another image in a similar spirit, see “Thurston's Jewel”.
Computation and rendering
The following procedure was used to create the image:
- Compute generators of the quasi-Fuchsian group from the shear-bend parameters using Mathematica
- Generate the limit set as a postscript file, using Curt McMullen's program lim
- Convert the limit set to a list of (center,radius) tuples for the spheres, using lim2pov
- Scan the background from a mimeographed copy of Thurston's lecture notes (page 8.36 in the original numbering)
- Integrate the background image and spheres (with glass texture, refraction, reflection, etc.) in a POV-Ray scene file.
- Render horizontal slices of the scene in parallel on several computers (using a total of 726 CPU-hours)
- Combine the slices using assembleppm, and convert to a reasonable image format (PNG)