Volumes in Paraview Connector

Can a temperature vdb be saved to OV?

The new connector is awesome and VDBs are saved reliably. I am currently rendering in Houdini and need at least Density and Temperature VDBs. It appears that only the density VDB is saved. I tried using the PassArray filter, but still get only density VDB. I tried disabling the “Preclassified Volume Output”, but still get only density VDB.
Also, I don’t understand the ovdbdensityfield and ovdbdiffusefield. I assume the diffuse field is generated from the Paraview Colormap. But, I don’t see this in Houdini. They appear to be embedded in the saved VDB file.

Hello @bjcarve! I’ve asked the dev team for some assistance with your question. In the meantime, if you haven’t already, take a look at our documentation here: ParaView — Omniverse Connect documentation

the passArray will output a single VDB with multiple channels in it. if you want separate vdbs you can add just output each channel you want separate and it will make a vdb for each selected

The fields selected in PassArrays will end up in the USD file, but regretfully not as grids in the VDB itself. Only the field selected in the “coloring” dropdown of the properties panel will be transferred. Since @bjcarve contacted me offline, I assume his manual solution is sufficient for the moment:

  • Renormalize the data fields manually using ParaView filters
  • Select each field one-by-one, and copy the resulting VDB out to desired “density” and “temperature” VDBs
  • From what I understood, the fields can be merged in Houdini, and the channels accessed separately.

I’m considering adding functionality to make this process (ie. multiple field->grid mapping and renormalization) more user-friendly in ParaView.

The current OV/Paraview connector downloads density, although it is possible to select another data field (i.e. temperature) and it will be saved but with the name density. That is a work around at this point.

Brad Carvey


This approach has been working for me.

Brad Carvey



Hi Brad, the latest version of the PV Connector allows for more control over which fields end up in the final VDB. Essentially, if you use a Pass Arrays filter, all selected fields - albeit only those with the same layout, cell or point, as the one used for coloring - will end up as a grid in the VDB by the name of their field array. So a ‘Pres’ field will become a ‘Pres’ grid in the VDB. For reference, see the last paragraph on Direct Source Field Array Output in the manual.

I installed Sandia’s version of Paraview 11 and added the OV connector. Everything seems to work. I am evaluating the VDBs now.

Running Paraview 11 and OV paraview 11 connect.
I load the wavelet source.
Add OV viewport.
Change “Representation” to Volume.
Works great.
Load my data.
Cell to Point data
add Resample to Image (now have rect grid, just like wavelet
add OV viewport
Change to representation to volume
The session folder and files are created correctly
Volume never appears and after about 10-20 seconds Paraview 11 crashes