You are attempting to apply a "projection matrix" to a "model view
matrix". The transforms applied in TransformGroups are referred to as
"modelview" transforms because they merely place objects in the virtual
world coordinate system. Once all the objects are placed, they are all
run through the current "projection" transform.
Take a look at the View class (which controls the projection transform),
specifically at View.setProjectionPolicy(),
View.setLeftProjection(Transform3D) and
View.setRightProjection(Transform3D).
The API docs for BadTransformException say:
* Transforms that are used in the scene graph, within a TransformGroup
node, must be affine. (snip)
(snip)
* The projection transform is allowed to be non-affine, but it must
either be a single point perspective projection or a parallel
projection. (snip)
The first bullet applies to you since you are attempting to use a
perspective projection transform (non-affine) in a TransformGroup.
-Lee
> -----Original Message-----
> From: alark joshi [mailto:[EMAIL PROTECTED]]
> Sent: Tuesday, May 08, 2001 7:02 AM
> To: [EMAIL PROTECTED]
> Subject: [JAVA3D] Problems with Perspective Projection
>
>
> Hi,
> I am working on a mathematical model which I have represented
> in Java3D. I
> am able to view the model using lookAt() and ortho(). But if I use
> perspective() or frustum() on the same Transform3D object, it
> gives me the
> following error. I tried changing the object to a simple Cube, but it
> still gives me this error.
>
> Exception in thread
> "main" javax.media.j3d.BadTransformException: TransformGroup:
> non-affine
> transform at
> javax.media.j3d.TransformGroup.setTransform(TransformGroup.java:108)
>
>
> I have no idea why this is happening. According to the error
> description
> in the API, it should not give an error if I am using perspective
> projection to one point (which is exactly what I am doing).
>
> Please could you let me know what might be the problem.
> Thanks a lot,
> Alark Joshi
>
> ==============================================================
> =============
> 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".
>
===========================================================================
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".
