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From: paul@hpfclk.UUCP
Newsgroups: net.math
Subject: ray meets sphere - (nf)
Message-ID: <3545@hp-pcd.UUCP>
Date: Fri, 30-Dec-83 03:48:12 EST
Article-I.D.: hp-pcd.3545
Posted: Fri Dec 30 03:48:12 1983
Date-Received: Sun, 1-Jan-84 02:21:54 EST
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Organization: Hewlett-Packard, Fort Collins, CO
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#N:hpfclk:6300003:000:418
hpfclk!paul    Dec 27 10:46:00 1983


Any references/helpful hints to this problem would be greatly 
appreciated - we have a solution but am curious if it is the
best (w.r.t. number of operations).

What is the quickest way to determine if a ray intersets a sphere?
  (the origin of the ray may be inside/outside the sphere)

The solution we have takes 8 additions, 7 multiplies, 1 divide, and
3 compares.

			    Paul Beiser
			
			...hplabs!hpfcla!paul