# Camera (View) Matrix - Help

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### #1ajit_kamat

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Posted 14 June 2005 - 09:40 AM

Hi,

I am having hard time understanding the camera (view) matrix:

Ux Vx Nx 0
Uy Vy Ny 0
Uz Vz Nz 0
-E.U -E.V -E.Z 1

How is this matrix constructed?
Why are there dot products in the translation section of this matrix?
How is rotation and translation actually achieved by this matrix?

Cheers,

~Ajit

### #2anubis

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Posted 14 June 2005 - 01:22 PM

U, V and N are generally known as the camera vectors. U is your view vector. the camera looks into this direction. the V vector is a vector you choose. it has to be orthogonal to the U vector. finally the N vector is the cross product of U and V, thus forming a cartesian coordinate system. all that is left is to find out is the translation part... usually it is just the negative of the camera's position.

i don't know what E and Z are... could you clarify on that ? i assume that E is the eye or camera position ?
If Prolog is the answer, what is the question ?

### #3anubis

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Posted 14 June 2005 - 01:38 PM

assuming that the last part of the translation is actually -E.N your are technically rotating E from camera to world coordinates, taking the negative of each component
If Prolog is the answer, what is the question ?

### #4ajit_kamat

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Posted 15 June 2005 - 04:55 PM

yep, you are right it should be -E.N. Thank you for the reply.

~Ajit

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