From topper@haydn.chm.uri.edu  Fri Dec  4 09:11:45 1992
Date: Fri, 4 Dec 92 14:11:45 -0500
From: topper@haydn.chm.uri.edu (Robert Q. Topper)
Message-Id: <9212041911.AA14051@haydn.chm.uri.edu>
To: chemistry@ccl.net
Subject: Re:  Random Distribution of Points on a Sphere


In response to Dongchul's question,

> Hi fellow chemists,
> This may fit better in comp.graphics, but someone in this group
> may have experienced it already. So here it goes.
> I want to generate points on the surface of a sphere as randomly
> as possible. These points may be used for drawing van der Waals
> surface of an atom. I tried with symmetrically distributed points
> (generated by varying phi and theta, etc), but due to symmetry,
> the points looked like marching ants at certain angles.
> Since many of symmetrically distributed points are likely to be
> overlapped when they are placed in 2-D screen, increasing the
> density of VDW points would require unnecessarily large number
> of sphere points. Random distribution of points would help
> minimizing the number of points required and will give a better
> appearance.
> Any ideas?
> -DCL
> lim@rani.chem.yale.edu

Check Appendix G.4 of Allen and Tildesley's wonderful book
"Computer Simulation of Liquids" (Clarendon Press, Oxford, 1987)
for an algorithm for uniformly sampling the surface of a sphere.

-RQT


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