Say I have a Transform3D that has some arbitrary rotation and translation.
I want to further roatate it around the stationary y-axis. Do I:
1. Make an AxisAngle object with (0,1,0,angle)
2. Make a new Transform3D and set it equal to my AxisAngle object
3. Multiply the original Transform3D object by my new Transform3D?
Daniel
> -----Original Message-----
> From: Lily Lee [SMTP:[EMAIL PROTECTED]]
> Sent: Tuesday, January 25, 2000 3:18 AM
> To: [EMAIL PROTECTED]
> Subject: Re: [JAVA3D] vexing rotation problem...
>
> AxisAngle is the right thing to do, and the most efficient. There is
> a direct relation from axis/angle to the 4 by 4 3D transformation
> matrix. You can find the formular from any robotics text book--look
> for the twist/screw representation. Another alternative is the
> quaternion, but that still involves the axis and angle of rotation.
>
> Lily Lee
>
> >
> > Hey All,
> >
> > I'm having a particularly vexing rotation problem. I want to be able to
> > rotate around multiple axes simultaneously. Currently, I perform the
> > multiple rotations by creating 3 Transform3D's, and using rotX(xAngle)
> on
> > one, rotY(yAngle) on another, and rotZ(zAngle) on the third. Then I
> > multiply the 3 together in the order xTransform*yTransform*zTransform.
> This
> > works fine. Unless....
> >
> > Say yAngle is 90 degrees. Then, due to the order of the rotations given
> > above, rotations about x and z have the same effect- they both rotate
> about
> > the z axis.
> >
> >
> > I believe the way to solve this may be to use the AxisAngle object to
> set
> > Transform3D. If I can form orthogonal vectors, and use AxisAngle to
> rotate
> > around them, wouldn't this work? Or would there be a more efficient (ie
> > faster) method?
> >
> > Thanks,
> > Evan Drumwright
> >
> >
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