A computer program for topographic analysis of biomolecular systems.

Abstract This program essentially generates a picture of a space filling molecular model. By precise simulation of the intersections between atoms, leaving out the ‘hidden line’, a good perspective is produced. Additional three dimensional information is provided by simulating reflection spots on the surface. This program has been used to visualise three dimensional surface features of biologically important molecules (e.g., valinomycin). With slight modification the program can be used to visualise enzyme active sites and receptor surfaces. It can also be used to create animated motion pictures of molecular dynamics.