Hi Utkarsh,

Yes, I had connected the reader or source directly to the filter with no other filters intervening.

I have used the keys for a number of things. In addition to passing meta data I also implemented dynamic load balancing in a couple of algorithms by passing vtkObjects. For example the demand loading strategy in our stream tracer expects to receive a reader object in the pipeline information. The reader object also implements a LRU block cache to reduce I/O footprint.

We've used a similar strategy to generate seed cell geometry on demand, where our volume source passes a cell generator object downstream in the pipeline information which the stream tracer uses to access any cell in any order (dynamic load balancing part) with a minimum communication and memory footprint. We did that because we ran our of memory when both the source and the stream tracer had a copy of the seed geometry.

The use case I'm describing is the generation of topographic maps of the magnetosphere which in the 3D case requires 10's of millions of stream traces and the seed geometry is colored in the mapper output. Dynamic load balancing of the stream tracing provides a nice speed up.

The vtkPVPostFilter looks to add nice new features to extracting components form vectors and converting cell to point data and so on. I do see why PV can't copy keys from input to output blindly. But, do you think vtkPVPostFilter could copy the information from input to output as well? It doesn't after all modify the existing arrays or geometry (if I'm reading it right it only adds arrays if they are requested).? Or is there another work around that would get our filters working again?

Thanks
Burlen

On 05/05/2011 05:51 AM, Utkarsh Ayachit wrote:
Burlen,

Keys are not propagated by pipeline by default. So your approach would
only work when there's no other filter between the reader and your
filters. With ParaView 3.10, vtkPVPostFilter get inserted always into
the pipeline after every algorithm. As a result your keys maybe
getting eaten up by the post-filter.

What keys are these?

Utkarsh

On Wed, May 4, 2011 at 10:35 PM, Burlen Loring<blor...@lbl.gov>  wrote:
Hi All,

I have a reader that gets the information object from it's output and adds
some keys for downstream filters to use. This recently stopped working with
version 3.10. Can anyone shed some light on what might have caused the
change in behavior in version 3.10? Was this a deliberate change?

Thanks
Burlen

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