[vtkusers] Ghost level request

[Simon Latapie]

Hello vtkusers,

I am working on a parallel reader, and I am trying to understand the way 
ghost levels are propagated and required by filters in the VTK pipeline.

I am using the VTK source tree of a Paraview 3.4.0 release.

What I understand is ghost level is given by the end of the pipeline, 
and every filter has to inject this information into his input, to 
propagate the information.

I used a pipeline with three paraview servers, one client, a distributed 
unstructured grid as the data, and the D3 (DistributedDataFilter) filter 
in which I check the requested ghost level (I retrieve the ghost level 
value with the method:
outputInfo->Get(vtkStreamingDemandDrivenPipeline::UPDATE_NUMBER_OF_GHOST_LEVELS())
).

Unfortunately the only filter I found that requires a ghost level > 0 is 
the CellDataToPointData one.

Are there other filters that request a ghost level > 0 ? Don't the 
parallel stream tracer filter, or the Contour one, require a non zero 
ghost level to correctly interpolate between distributed data ?

Regards,

-- 
Simon Latapie