If you want to use the lookAt, frustrum, etc. tranformations directly on View,
the compatibility mode has to be set. Maybe that's what missing.
regards
Paul
alark joshi schrieb:
> For some reason, whatever changes I make to a View never seem to change my
> viewpoint in any way. I define a View() and set its ProjectionPolicy, and
> then whatever Transfor3D matrix I use to transform the object, it is not
> happening. I cant seem to see what I am missing.
> Thanks,
> Alark
>
> On Tue, 8 May 2001, J. Lee Dixon wrote:
>
> > 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
> > >
> > > ==============================================================
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> > >
> >
>
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