5) When the view platform attach policy is NOMINAL_HEAD, scaling about
the center of the view platform has no effect in a perspective
projection.  The objects get proportionally smaller and closer to the
viewer making their projection the same size in clipping coordinates.
You can see other examples of this phenomenon by putting a scale
transform directly above the view platform: it will have no effect.
When the view platform attach policy is NOMINAL_SCREEN, then the
scaling is centered about the screen and the scale does have an
effect.  In parallel projection mode, the distance from the screen has
no effect on the rendering so the scale has an effect regardless of
where the scale is centered.  This is counter-intuitive and we are
examing whether we can change this behavior for Java 3D 1.2.


6) This is a bug.  We'll fix it in a subsequent release of Java 3D.

--
Kevin Rushforth
Java 3D Team
Sun Microsystems

[EMAIL PROTECTED]


>Date:         Sun, 12 Sep 1999 12:09:14 -0700
>From: Jon Barrilleaux <[EMAIL PROTECTED]>
>Subject:      [JAVA3D] view model (by trial and error) - contd.
>To: [EMAIL PROTECTED]
>
>this is a continuation of my earlier post regarding trying to divine
>the view model through empirical evidence.  If anyone can confirm,
>deny, or answer the following questions I'd appreciate it...
>
>BTW: My system is NT 4.0, Open GL, Java 3D 1.1.2, Java 1.2 and 1.3
>beta.
>
>5) If the window eyepoint policy is RELATIVE_TO_FIELD_OF_VIEW a window
>resize policy of VIRTUAL_WORLD only seem to work if the projection
>policy is PARALLEL_PROJECTION.  Window movement seems to work.
>Shouldn't they both work or not work for a particular mode of window
>eyepoint policy?  (Perhaps this is due to the coupling between modes
>where some control eyepoint Z and others only control eyepoint X-Y.)
>
>6) Operations that require display update when the display window
>moves (like some window movement and window eyepoint policies) only
>works sometimes.  Often the display fails to update after a move.
>Hiding and showing the window or resizing it forces the update.  (Java
>3D/Java should be doing this automatically all the time -- right?)
>
>BTW:   Although the Java 3D view model is more "sophisticated" than
>previous ones was it also intended to be easier to use in any
>particular way?
>
>--jon
>____________________ Peculiar Technologies ____________________
>Jon Barrilleaux       3800 Lake Shore Ave.         Purveyors of
>[EMAIL PROTECTED]        Oakland, CA 94610      Alternate Reality
>510.444.4370 voc                           Augmented Simulation
>510.444.0231 fax        www.augsim.com         and 3D Solutions
>
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