[Paraview] Volume Rendering 17GB 8.5 billion cell volume

[David Trudgian]

Hi,

We have been experimenting with using Paraview to display very volumes from very
large TIFF stacks generated by whole-brain microscopy equipment. The test stack
has dimensions of 5,368x10,695x150. Stack is assembled in ImageJ from individual
TIFFs, exported as a RAW and loaded into paraview. Saved as a .vti for
convenience. Can view slices fine in standalone paraview client on a 256GB machine.

When we attempt volume rendering on this data across multiple nodes with MPI
nothing appears in the client. Surface view works as expected. On switching to
volume rendering the client's display will show nothing. There are no messages
from the client or servers - no output.

This is happening when running pvserver across GPU nodes with NVIDIA Tesla
cards, or using CPU only with OSMESA. pvserver memory usage is well below what
we have on the nodes - no memory warnings/errors.

Data is about 17GB, 8 billion cells. If we downsize to ~4GB or ~9GB then we can
get working volume rendering. The 17GB never works regardless of scaling
nodes/mpi processes. The 4/9GB will work on 1 or 2 nodes.

Am confused by the lack of rendering, as we don't have memory issues, or an
other messages at all. Am wondering if there are any inherent limitation, or I'm
missing something stupid.

Thanks,

Dave Trudgian