Re: A92: 3D rotation of plots
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Re: A92: 3D rotation of plots
At 15:57 13/01/99 -0500, you wrote:
>
>Nathan Mueller on this list told me that you can rotate a plot m degrees
>around the z axis by doing the following:
>|cos(m) sin(m) 0| |x|
>|-sin(m) cos(m) 0|* |y|
>|0 0 1| |z|
>
>now, how do you rotate a plot around the x and y axes? Thanks!
>--TurboSoft
>
>Visit the TurboSoft Homepage: The most current Basic programs created by
>TurboSoft for the 89.
><A HREF="http://members.aol.com/turbosoft/turbosoft.html">
>http://members.aol.com/turbosoft/turbosoft.html
>
You should use a 4x4 matrix. (like Direct3D) Why ? because
with a 3x3 matrix you can't make a translation.
Whereas with a 4x4 matrix :
[ 1 0 0 0]
[ 0 1 0 0]
[ 0 0 1 0]
[ tx ty tz 1]
rotation around x :
[ 1 0 0 0 ]
[ 0 cosa -sina 0 ]
[ 0 sina cosa 0 ]
[ 0 0 0 1 ]
etc...
you can add the two matrix, and it will do a rotation and a translation
at the same time. powerful !!
Benoit SCHERRER
References: