# XML property to disable scalar mapping and slice view for vtkMultiBlockDataSets

**URL:** https://discourse.paraview.org/t/xml-property-to-disable-scalar-mapping-and-slice-view-for-vtkmultiblockdatasets/7190
**Category:** Feature Requests
**Created:** [May 10, 2021, 9:56am UTC](https://discourse.paraview.org/t/xml-property-to-disable-scalar-mapping-and-slice-view-for-vtkmultiblockdatasets/7190 "2021-05-10T09:56:23Z")
**Posts on this page:** 3
**Page:** 1

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### Author: ![Jonas.Lukasczyk](https://discourse.paraview.org/user_avatar/discourse.paraview.org/jonas.lukasczyk/32/5839_2.png) [@Jonas.Lukasczyk](https://discourse.paraview.org/u/Jonas.Lukasczyk)
#### Post date: [May 10, 2021, 9:56am UTC](https://discourse.paraview.org/t/xml-property-to-disable-scalar-mapping-and-slice-view-for-vtkmultiblockdatasets/7190/1 "2021-05-10T09:56:24Z")

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Hi all,  
TTK now comes with a whole deferred rendering framework as described here: [[2010.03936] Cinema Darkroom: A Deferred Rendering Framework for Large-Scale Datasets](https://arxiv.org/abs/2010.03936)

Many of these filters process vtkImageData objects and produce actual rgba color scalar arrays. To look at the colors directly one always has to disable the “Map Scalars” display property in ParaView. It would be great if one could specify this in the XML file just like the preferred representation type.

These filters can also process lists of images that are represented as a vtkMultiBlockDataSet where each block is an image. Although PV offers the slice representation in the drop down menu for such a vtkMultiBlockDataSet, choosing that option results in the following error:  
vtkPVDataRepresentationPipeline (0x558cdf17b140): Can not execute simple algorithm without output ports

So the only way to currently inspect the image set is to select the surface representation which produces a lot of geometry for a set of full HD images.

So does anyone know if these issues would just require a quick fix or if this is something more substantial? If you point me in the right direction I can also try to fix this myself and open a PR.

Best  
Jonas Lukasczyk

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### Author: ![mwestphal](https://discourse.paraview.org/user_avatar/discourse.paraview.org/mwestphal/32/17_2.png) [@mwestphal](https://discourse.paraview.org/u/mwestphal)
#### Post date: [May 10, 2021, 9:57am UTC](https://discourse.paraview.org/t/xml-property-to-disable-scalar-mapping-and-slice-view-for-vtkmultiblockdatasets/7190/2 "2021-05-10T09:57:26Z")

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This is neat and simple to implement imo.

FYI @Charles_Gueunet 🙂

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### Author: ![Jonas.Lukasczyk](https://discourse.paraview.org/user_avatar/discourse.paraview.org/jonas.lukasczyk/32/5839_2.png) [@Jonas.Lukasczyk](https://discourse.paraview.org/u/Jonas.Lukasczyk)
#### Post date: [June 10, 2021, 1:50pm UTC](https://discourse.paraview.org/t/xml-property-to-disable-scalar-mapping-and-slice-view-for-vtkmultiblockdatasets/7190/3 "2021-06-10T13:50:27Z")

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Hi all,  
I investigated the slice representation (`vtkImageSliceRepresentation`) of `vtkMultiBlockDataSets`. The documentation of this filter already states: “Currently, it does not support composite datasets, however, ​we should be able to add such a support in future.”

To me it seems the class is heavily specialized to represent just one object as one slice (there is only one actor, mapper,… member), so changing the class to create actors for all elements of a composite dataset seems overkill. I think it would be nicer to provide that logic at a higher level where the representation is selected for the dataset, and then the ImageRepresentation is applied element-wise. Any thoughts on how and if this can be accomplished?
