Re: 3d programming

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#39

From: J. Szamosfalvi
Date: Sat, 24 Feb 1996 09:41

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David Matiskella (matiskel@aa.washington.edu) wrote:
: > In other words a point is not a vector and a vector is not a point.  Also, two
: > points do not necessarily make a vector.  A vector is a point that *points*
: > somewhere
: But a point has a magnitude and direction. Point x,y,z has a magnitude 
: of sqrt(x^2+y^2+z^2) and a direction of ( x i y j z k)/magnitude where 
: i,j,k are the unit vectors. Remember when you define a point in space you 
: are referencing it to some reference point.  

Yes, you do reference it to some reference point, but there's no such 
thing as an implicit vector from your point of reference (call it zero)
to your chosen point.   If there's a vector, it's explicit, and it 
doesn't need to start/end in your point of reference.

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Path: arc1-ca.pugleaf.net!saul7.u.washington.edu!szamos
From: szamos@saul7.u.washington.edu (J. Szamosfalvi)
Newsgroups: comp.lang.pascal.borland,comp.lang.pascal.mac,comp.lang.pascal.ansi-iso,comp.lang.pascal.misc,comp.sys.amiga.programmer,comp.graphics.algorithms,comp.os.ms-windows.programmer.graphics,comp.sys.amiga.graphics
Subject: Re: 3d programming
Followup-To: comp.lang.pascal.borland,comp.lang.pascal.mac,comp.lang.pascal.ansi-iso,comp.lang.pascal.misc,comp.sys.amiga.programmer,comp.graphics.algorithms,comp.os.ms-windows.programmer.graphics,comp.sys.amiga.graphics
Date: 24 Feb 1996 09:41:01 GMT
Organization: University of Washington
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