[Paraview] Bug in volume rendering of unstructured grids on server

[Cory Quammen]

Dear all,

I am attempted to do client/server rendering of an unstructured grid
using ParaView 3.12 that I have compiled myself on a RedHat system
with two NVIDIA Quadro FX 5000 graphics cards. I have built ParaView
from the v3.12.0 tag. To summarize, the problem is that only a subset
of the unstructured grid data is rendered.

Here is what I have done so far to attempt to identify the problem.

1). Start the server on 4 cores. Start the client and connect it to the server.
2). Add a Wavelet source with the default parameters. I have the Edit
-> Settings -> Render View -> Server -> Remote Render Threshold set to
0 MBytes to force server side rendering, so 4 windows titled
"Visualization Tookit - OpenGL" appear right away. They are stacked
neatly on top of each other and the contents of the windows are all
black.
3). Change the Representation to Volume. Everything renders in
ParaView as expected. The content of the rendering windows from the
server stay black.
4). Add a Tetrahedralize filter connected to the Wavelet source.
5). Change the Representation to Volume. Now the problems begin.
First, the content of the rendering windows is no longer black. It is
the same as the content in the ParaView display except that the
background color in the server window is black instead of the gray
background I have in the ParaView display. Also, only a subset of the
data is volume rendered. If I move the top window in the stack of
windows from the server, I see more data in ParaView, and in the
window that has been revealed is a different subset of the data set.
If I rearrange the windows so that they are all on top of all other
windows, I can see the whole data set volume rendered. However, if any
of the windows are covered up or go offscreen, then the portion of the
data set that is covered or off the screen does not appear in
ParaView.
6). If I change the Representation back to Surface, the view in
ParaView now suffers the same way as when the Representation was
Volume. The same is true for Outline, Points, Surface with Edges, and
Wireframe representations.

Clearly, the volume representation for unstructured grid data sets is
causing a change in the way rendering is carried out on the server. If
I can guarantee that the windows from the server are uncovered, then
volume rendering of unstructured grids seems to work. However, this
seems unnecessary considering how the other representations don't
appear to have this requirement.

Can anyone shed some light on what might be going on here?

By the way, I have confirmed that I have the same problem on a
different system with Fedora 14 installed.

Thanks,
Cory

-- 
Cory Quammen
Research Associate
Department of Computer Science
The University of North Carolina at Chapel Hill