Gregory Buck ......Science: entanglement rates and patterns.........ropelength......... the dynamics and mechanics of strings and masses....... radiating tubes.......the geometry and topology of life.......Fiction: machine parts ...... Music: songs....Library: ..pdfs...mp3s..
	Accessibility and occlusion of biopolymers, ray tracing of radiating tubes, and the temperature of a tangle Gregory Buck, Robert G. Scharein, Jeffrey Schnick, Jonathan Simon
	We introduce a measure of complexity, an energy, for any conformation of filaments. It is the occlusion, the portion hidden when viewed from an arbitrary exterior point. By inverting we get the exposure, a first approximation of the accessibility of the filaments. Assuming the filament is a source, we get the self-irradiation, which leads to both an interpretation as the temperature and a novel visualization technique: ray tracing as a virtual laboratory. There is a wide variety of applications, from enzyme action on and radiation damage of biopolymers, to the geometry of light bulb filaments. Energy minimization provides automatic detangling, resulting in symmetric and pleasing conformations.
	Figure 2. Occlusion and accessibility as the “inverse” of self-radiation and temperature. 2A (self radiation) was created via raytracing. 2B is simply the inverse image via Photoshop, and accessible regions are light colored, occluded ones are “shadowed”. This illustration was suggested by Felice Frankel.
	Here is the pdf of the paper.