Greg M. Johnson <gregj;-)565### [at] aolcom> wrote:
> Given a "vector"  <a,b,c>,  povray thinks of this as a vector with one end
> at origin, the other at <a,b,c>.  I'm assuming this would answer your
> question.

  Mathematically speaking, you are confusing a vector with a line segment.

  They are not the same thing. A vector does *not* have two points. A
vector has a single point, which describes solely its direction and length.
A vector can also be represented by two angles and a scalar (representing
its length), nothing more.
  A line segment consists of two points: A starting point and an ending
point. This is effectively more than a vector since it places the vector
at certain coordinates.

  Your sentence "povray thinks of this as a vector with one
end at the origin, the other at <a,b,c>" is not accurate, and not
only because a vector does not have two endpoints, but because
there are several places where POV-Ray does not "think" a vector
as starting from the origin (eg. smooth triangle vertex normals, or
the normal vector return value of trace()).

-- 
#macro N(D)#if(D>99)cylinder{M()#local D=div(D,104);M().5,2pigment{rgb M()}}
N(D)#end#end#macro M()<mod(D,13)-6mod(div(D,13)8)-3,10>#end blob{
N(11117333955)N(4254934330)N(3900569407)N(7382340)N(3358)N(970)}//  - Warp -

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