I think you need to explain this a little more.  Getting a rotation from
points would require a little more explanation.




At 08:37 PM 09/30/2001 -0400, you wrote:
>Thanks...
>
>I tried something similar to this but I instantiated the Transform3d with
>the rotation matrix as one of the constructor's parameters.  The API
>reference says you can do this but it didn't work.  I'll try your
>suggestion (using setRotation) and see if that does the trick.
>
>Oh, one more question... is there an easy way to create a rotation matrix
>based on a pair of Points or Vectors describing two endpoints?  I don't
>necessarily know the angle for rotations.  Sometimes I start with the
>endpoints.
>
>-- John
>
>On Sun, 30 Sep 2001, Eric Reiss wrote:
>
> > Date: Sun, 30 Sep 2001 13:48:34 -0400
> > From: Eric Reiss <[EMAIL PROTECTED]>
> > Reply-To: Discussion list for Java 3D API <[EMAIL PROTECTED]>
> > To: [EMAIL PROTECTED]
> > Subject: Re: [JAVA3D] How to rotate objects?
> >
> > This is actually very simple.
> >
> > Suppose you already know the TransformGroup for an object you want to
> > rotate to a specific angle around the X axis.  Lets call this Object
> > TransformGroup JohnTG.
> >
> > Transform3D tempT3D = new Transform3D();
> > (JohnTG).getTransform(tempT3D);
> >
> > Matrix3d someRotationMatrix = new Matrix3d();
> > someRotationMatrix .setIdentity();
> > someRotationMatrix .rotX(Math.PI/2.0); //  This angle is whatever you want
> > to make it.
> >
> > tempT3D.setRotation(someRotationMatrix );
> > (JohnTG).setTransform(tempT3D);
> >
> >
> > If you want to rotate around more than just the X axis, then do your rotY
> > and rotZ in the XYZ order and do it immediately after the rotX method and
> > before the setRotation method.
> >
> >
> >
> >
> > At 01:35 PM 09/30/2001 -0400, you wrote:
> > >All,
> > >
> > >I've run into a problem that neither the Java3d examples or the Sun API
> > >reference seem to be able to explain to me.... and that is how to perform
> > >rotation traansforms.  All the examples I've seen either use a mouse event
> > >or an Alpha/Interpolator.... but all I want to do is just create a
> > >cylinder and rotate it to a specific orientation in three-space.
> > >
> > >Sounds pretty simple but I haven't been able to figure it out from the
> > >tools available.
> > >
> > >Now, I will tell you that I have tried creating a Maatrix3d, normalizing
> > >it and then doing rotX, rotY and rotZ and then pumping that into a
> > >Transform3d.  But this doesn't actually seem to do anything.
> > >
> > >Can anyone post some example code or point me to the right place?
> > >
> > >-- John
> > >
> > >--
> > >_____________________________________________________
> > >
> > >John T. Nelson
> > >President               |    Computation.com Inc
> > >mail:                   |    [EMAIL PROTECTED]
> > >company:                |    http://www.computation.com/
> > >journal of computation: |    http://www.computation.org/
> > >_____________________________________________________
> > >"Providing quality IT consulting services since 1992"
> > >
> > >=======================================================================
> ====
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> body
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> > >[EMAIL PROTECTED] and include in the body of the message "help".
> >
> > ***********************************************************************
> > Eric N. Reiss
> > MEMS Manager
> > Swanson Center for Product Innovation
> > Department of Mechanical Engineering
> > School of Engineering  - University of Pittsburgh
> >
> > 3700 O'Hara Street
> > 647 Benedum Hall
> > Pittsburgh, Pennsylvania 15261
> > Phone: 412-624-9696
> > FAX: 412-624-7701
> > Email: [EMAIL PROTECTED]
> > http://www.sigda.org/Eric/
> > ***********************************************************************
> >
> > ===========================================================================
> > To unsubscribe, send email to [EMAIL PROTECTED] and include in the body
> > of the message "signoff JAVA3D-INTEREST".  For general help, send email to
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> >
>
>--
>_____________________________________________________
>
>John T. Nelson
>President               |    Computation.com Inc
>mail:                   |    [EMAIL PROTECTED]
>company:                |    http://www.computation.com/
>journal of computation: |    http://www.computation.org/
>_____________________________________________________
>"Providing quality IT consulting services since 1992"
>
>===========================================================================
>To unsubscribe, send email to [EMAIL PROTECTED] and include in the body
>of the message "signoff JAVA3D-INTEREST".  For general help, send email to
>[EMAIL PROTECTED] and include in the body of the message "help".

***********************************************************************
Eric N. Reiss
MEMS Manager
Swanson Center for Product Innovation
Department of Mechanical Engineering
School of Engineering  - University of Pittsburgh

3700 O'Hara Street
647 Benedum Hall
Pittsburgh, Pennsylvania 15261
Phone: 412-624-9696
FAX: 412-624-7701
Email: [EMAIL PROTECTED]
http://www.sigda.org/Eric/
***********************************************************************

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