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# Dot-Product

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What is a dot-product and what are the equations for this opperation?

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www.mathworld.com

All you ever wanted to know and more -
search for Dot Product and you should get a good 1st hit.

-Michael

[edited by - thr33d on December 16, 2003 4:23:55 PM]

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Hmm, not very many "straight" answers there though.

As I understand it, the DP returns how similar two vectors are.

0 being perpendicular
|u|*|v| being completely orthogonal

(DP is also equal to |u|*|v|*cos(angle between u and v) fyi)

it''s calculated as the sum of the product of each ... element/part? of the vector:

DP = u.x*v.x + u.y*v.y + u.z*v.z
for a 3d vector

-Michael

Thanks for info

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The easiest way to think about it is to think of a dop-product as the size of the angle between two vectors.

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Have a look at Chapter 61 in Abrash''s "Game Programming Black Book". The entire text of the book is available online at http://public.planetmirror.com/pub/gpbb.

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