Volume rendering is sometimes crashing with slice remote server.

Volume rendering is sometimes crashing with anything that creates a plane tool with remote server. Cory and I saw this, but I can't replicate it currently. However, artifacts are obvious. This is nuanced, and shows in numerous ways. Note that errors show up when local rendering (i.e., the dataset is small enough that we are rendering locally), but crashes when remote rendering. Here is how to replicate.

• 5.12.1, Linux, remote server. (I'm using 36 ranks).
• Edit/ Settings/ Render View/ Remote Rendering Threshold == 0. OK.
• Load g1s1-10fps.16.*. Apply.
• Color by ids. Volume Render.
• Slice. Z Normal. Apply.

Note that if you turn the Show Plane off, all looks fine.

As things didn't crash this time, here is a screenshot.

• Turn off Show Plane.
• Save State
• Reset Session
• Load State

For me, this crashed. On the ParaView side I get this warning, probably before the crash: (3092.893s) [paraview ] vtkOutputWindow.cxx:77 WARN| Warning: In vtkOpenGLProjectedTetrahedraMapper.cxx, line 312 vtkOpenGLProjectedTetrahedraMapper (0x108bd680): Intermixing translucent polygonal data with unstructured grid volumes is not supported! Either set opacity to 1.0 for polydata in the view or resample the unstructured grid to image data and use the ray cast mapper.

On the server side, probably after the crash, I get: Lots of: (3162.992s) [pvserver.3 ]vtkOpenGLProjectedTetra:312 WARN| vtkOpenGLProjectedTetrahedraMapper (0x10c34400): Intermixing translucent polygonal data with unstructured grid volumes is not supported!

Then: Lots of seg faults. I have a production/ release build of pvserver. I can build a debug version if required.

As per Cory, lets target at 5.13.1. If this requires a major or risky change, please move to 5.14.0.