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# Cross Products and axis'es

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Hi, I''m having a little trouble understanding this... Lets say I have axis A that passes through origin and axis B that starts (or passes through) a given point c1 and move in the direction of vector v1 from that point. If i need the cross product between axis A and axis B, do I need to consider the point c1 in this calculation? Or is [ C = A x B ] enough? Does this question make sense what so ever Thanks anyhow /Johan

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yes, it''s enough, you don''t need to know the start point of the vectors for a cross product.
C = A x B
the answer will be independant from the start point of each vector.

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It''s enough, because a vector has no position by itself.
That''s why you have ie a vector for the view direction of
a camera, and a position vector of the camera.
The normal vector you just calculated can "start" anywhere,
at (6,6,6), at (0,8,15) or (4,7,11)...
A vector that points into the direction of your normal,
and has the same length as your normal, is identical to your
normal, of course this is valid for vectors in general.
The "start point" of a vector is where you define it to be.
A vector is relative. If you declare a vector (1,2,3)
to start at the origin of a coordinate system, the vector equals the point (1,2,3) in that coordinate system. It''s just
how you see it.

It is now for sure you can throw away your computer

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