# vtkMultiBlockDataSet with vtkUnstructuredGrid blueprint

**URL:** https://discourse.paraview.org/t/vtkmultiblockdataset-with-vtkunstructuredgrid-blueprint/13668
**Category:** In Situ Support
**Created:** [January 11, 2024, 12:25am UTC](https://discourse.paraview.org/t/vtkmultiblockdataset-with-vtkunstructuredgrid-blueprint/13668 "2024-01-11T00:25:21Z")
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### Author: ![Alexandre\_Minot](https://discourse.paraview.org/user_avatar/discourse.paraview.org/alexandre_minot/32/7132_2.png) [@Alexandre\_Minot](https://discourse.paraview.org/u/Alexandre_Minot)
#### Post date: [January 11, 2024, 5:41pm UTC](https://discourse.paraview.org/t/vtkmultiblockdataset-with-vtkunstructuredgrid-blueprint/13668/4 "2024-01-11T17:41:38Z")

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Use ParaView to create your first Catalyst script. Load a result file from your simulation code, add a slice, then a VTPC extractor. Use file → save catalyst state. You will see that in the created python file, the file reader has been exported. That file reader has a registrationName=“something”. Replace the registration name content by the channel name you used on the simulation code side. Catalyst will use the Conduit channel instead of reading the file as the start of the pipeline.

Make sure you go through all the docs, as it can be a bit tricky to get started.

> [@How to try out Catalyst2](https://discourse.paraview.org/t/how-to-try-out-catalyst2/9008):
>
> Catalyst is an in-situ framework created as a part of ParaView a few years ago. With time and use, we saw the different drawbacks of our approach and then it was decided to create a new architecture, [Catalyst2](https://catalyst-in-situ.readthedocs.io/en/latest/index.html) With this new implementation, it is: easier to implement in your simulation (less knowledges required) easier to update from a version to another (less dependencies, binary compatibility) possible to activate Steering mode, where ParaView can modify simulation parameters at runtime A…

[https://catalyst-in-situ.readthedocs.io/en/latest/index.html](https://catalyst-in-situ.readthedocs.io/en/latest/index.html)

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