This describes my problem exactly, I believe the answer involves changing the
imageplate using the headtracked configuration. There is an example
of Java3D in a CAVE in a paper that was published in the May/June 1999 issue
of IEEE called "Projects in VR" : The Java3D API and VR.
Could we please have an example.
At 02:24 PM 6/30/00 -0500, you wrote:
>There have been several more posts on the subject but no response from
>Sun
> I don't know if this has fallen on deaf ears, or if I failed to explain
>the problem well enough. So I will attempt again.
>
>I have three machines, therefore three JVM's, three View's and three
>Canvas3d's that need to work as one to display on a Panoram GVR-120E
>projection screen. I have already implemented the networking at the
>Canvas3d level to guarantee the apps are in sync. It was disappointing,
>however, that I could not use the regular Java3D behavior system to do
>this, but that is another story...
>
>Here is a top-view diagram of the possible display configurations that
>we will be implementing.
>
>Diagram A represents the installed display system. The black curve line
>represents the screen surface. The yellow arrows are the direction of
>the three projections to the screen. One thing to note about this
>system is that each channel has a 25 degree overlap to it's neighbors.
>That is why our software must have perfect sync between views, thus
>deterministic execution of the behavior system. We do this through
>networking the frame's changes and swaps
>
>Diagram B shows ONE possible Java3D configuration, where each channel
>has different view offset, namely a rotation about the origin to the
>left or to the right for the left and right channels, represented by the
>green arrows. I have implemented this configuration just fine, however,
>as anyone who has done this knows, this is not the only way, and there
>can be a very noticeable "bowing" of the final view, due to the fact
>that the side views are rotated and not flat as in C. Often this is not
>a problem for a multi-channel display because even though the bowing
>occurs, the channel edges still match up perfectly. However, when the
>display overlaps, they DO NOT match up perfectly.
>
>Diagram C is what I need to create. The left and right channels are
>called off-axis projections. This is because the view direction does
>not run down the center of the viewing frustum as show by the green
>arrow and the blue triangle. The Blue triangle is the desired
>configuration. I know that this configuration has a great amount of
>distortion, but it is what we must have because of the overlap issues in
>B.
>
>Diagram D shows a typical multi-channel display that is flat. In this
>configuration, again off-axis projections are needed. As a fact of
>matter, any out-the-window or "fish-tank" VR system uses this technique
>to create the correct frustum when the view is tracked and not centered
>with respect to the display system.
>
>Now, I hope this illustrates my problem.
>The questions is, how do I set that view's frustum correctly to
>off-axis? I tried changing the ImagePlate and setting the view directly
>using VpToEc() among many other things with no success. Should I use a
>"head-tracked" configuration, even though there will be no
>head-tracking, to fool the system.???
Jack S. Gundrum
Visualization Group
Center for Academic Computing
Penn State University
Email:[EMAIL PROTECTED]
Phone:(814)865-1863
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