Math Question, operations with Vectors.

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Math Question, operations with Vectors.

Postby Auradrummer » Wed Nov 19, 2008 10:03 am

Hello All,
There are four math operations that I'm still in doubt.

I learnt tow things:
- when you have a matrix, you can rotate it to match a vector orientation
- you can do the inverse: rotate a vector to match the orientation of a matrix.

The questions I have are:
1. The difference between: dMatrix.TransformVector(dVector) and dMatrix.RotateVector(dVector) is that the first changes the size of the vector and second the direction of it?
2. The dMatrix.UntransformVector(dVector) and dMatrix.UnrotateVector(dVector) transforms the vectors to the global matrix, to the previous values they had or to another thing?

I'm studying math, but I'm still in early stages... but I'll arrive there someday!
Developing a racing game.
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Re: Math Question, operations with Vectors.

Postby Julio Jerez » Wed Nov 19, 2008 10:36 am

Tranform vector chnag eteh orientation and teh poition o f teh vector
rootate vector only chnge teh orientation

Rotatevector only multoply teh vector by teh first 3 x 3 element of teh matrix, those contahet teh rotation part,
Transform multiply the vetor by the 4 x 4 member of the matrix, teh last row in teh translation part.
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Re: Math Question, operations with Vectors.

Postby Auradrummer » Wed Nov 19, 2008 12:57 pm

Thnaks!

Ah, this is good, very good. But what makes the untransform? It divides the vectors instead multiply? This make possible to recover the previous values, right?
Developing a racing game.
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