# Development

**URL:** https://discourse.paraview.org/c/development/6.md?no_subcategories=false&page=21

[Latest](https://discourse.paraview.org/latest.md) · [Categories](https://discourse.paraview.org/categories.md) · [Tags](https://discourse.paraview.org/tags.md)

**Page:** 22

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## [Dihedral Angle calculation](https://discourse.paraview.org/t/dihedral-angle-calculation/7415)

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**Author:** [@Omarwan\_Hussein](https://discourse.paraview.org/u/Omarwan_Hussein)\
**Replies:** 0\
**Last updated:** [June 15, 2021, 7:50pm UTC](https://discourse.paraview.org/t/dihedral-angle-calculation/7415 "2021-06-15T19:50:27Z")

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I am working on a problem to calculate the dihedral angle between two spherical. I am using FeatureEdges Filter to do that, and specify the FeatureAngle. I am looking for a way to extract the Angle values in a spreadsh…

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## [vtkGhostType array missing](https://discourse.paraview.org/t/vtkghosttype-array-missing/7392)

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**Author:** [@moritz-h](https://discourse.paraview.org/u/moritz-h)\
**Replies:** 6\
**Last updated:** [June 14, 2021, 5:04pm UTC](https://discourse.paraview.org/t/vtkghosttype-array-missing/7392 "2021-06-14T17:04:42Z")

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I’m working on a filter which requires a rectilinear grid with ghost cells and I want to know which cell is a ghost cell when running an algorithm on the dataset. To my current understanding the vtkGhostType array is mea…

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## [The return value of the server side object method call with one or more parameters](https://discourse.paraview.org/t/the-return-value-of-the-server-side-object-method-call-with-one-or-more-parameters/7389)

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**Author:** [@Petr\_Melnikov](https://discourse.paraview.org/u/Petr_Melnikov)\
**Replies:** 5\
**Last updated:** [June 14, 2021, 10:28am UTC](https://discourse.paraview.org/t/the-return-value-of-the-server-side-object-method-call-with-one-or-more-parameters/7389 "2021-06-14T10:28:09Z")

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Dear Experts, Does paraview provide the way to get the return value of the server side object method call with one or more parameters? I know about properties with “information\_only” attribute, but this feature is suit…

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## [Tree widgets and check-state](https://discourse.paraview.org/t/tree-widgets-and-check-state/4146)

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**Author:** [@utkarsh.ayachit](https://discourse.paraview.org/u/utkarsh.ayachit)\
**Replies:** 33\
**Last updated:** [June 9, 2021, 7:18pm UTC](https://discourse.paraview.org/t/tree-widgets-and-check-state/4146 "2021-06-09T19:18:56Z")

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I have conundrum; figured I’d solicit feedback publicly. Here’s the context: I am working on a new Extract Block filter that extracts blocks using names/paths instead of some internal ids (as it currently does) which a…

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## [GPU Ray casting with HIDDENCELLS](https://discourse.paraview.org/t/gpu-ray-casting-with-hiddencells/7376)

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**Author:** [@jfavre](https://discourse.paraview.org/u/jfavre)\
**Replies:** 0\
**Last updated:** [June 8, 2021, 12:34pm UTC](https://discourse.paraview.org/t/gpu-ray-casting-with-hiddencells/7376 "2021-06-08T12:34:32Z")

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I am having difficulty in blanking cells from a vtkImageData because my experience shows that there seems to be an offset of one cell in each direction where \[some\] cells marked HIDDENCELL are rendered nonetheless. The a…

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## [Change Filter Inputs Before Apply](https://discourse.paraview.org/t/change-filter-inputs-before-apply/7346)

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**Author:** [@Jonas.Lukasczyk](https://discourse.paraview.org/u/Jonas.Lukasczyk)\
**Replies:** 3\
**Last updated:** [June 2, 2021, 12:27pm UTC](https://discourse.paraview.org/t/change-filter-inputs-before-apply/7346 "2021-06-02T12:27:28Z")

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Hi all, in PV it is currently only possible to access the “change inputs” dialog from context-menu of the pipeline-browser if the corresponding filter has been applied at least once. This is inconvenient for the followi…

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## [Use of Subprocess python module in programmable filter to print output from Shell script](https://discourse.paraview.org/t/use-of-subprocess-python-module-in-programmable-filter-to-print-output-from-shell-script/7325)

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**Author:** [@Pauly1](https://discourse.paraview.org/u/Pauly1)\
**Replies:** 0\
**Last updated:** [May 30, 2021, 2:06pm UTC](https://discourse.paraview.org/t/use-of-subprocess-python-module-in-programmable-filter-to-print-output-from-shell-script/7325 "2021-05-30T14:06:24Z")

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Hello, I’m trying develop a plugin (python programmable filter using util.vtkAlgorithm module) to use one of my existing program to do some processing. I would like the python script can display the output in the output …

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## [Plugin component order in paraview display](https://discourse.paraview.org/t/plugin-component-order-in-paraview-display/7319)

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**Author:** [@Pauly1](https://discourse.paraview.org/u/Pauly1)\
**Replies:** 0\
**Last updated:** [May 28, 2021, 11:47am UTC](https://discourse.paraview.org/t/plugin-component-order-in-paraview-display/7319 "2021-05-28T11:47:26Z")

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Hi, I’m currently using util.vtkAlgorithm Module to develop my own plugin with UI component in Paraview. Everything is going on well, except the order of UI component in the paraview interface is not very controllable/pr…

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## [Proposal: Catalyst V2 Bidirectional API](https://discourse.paraview.org/t/proposal-catalyst-v2-bidirectional-api/7258)

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**Author:** [@Francois\_Mazen](https://discourse.paraview.org/u/Francois_Mazen)\
**Replies:** 8\
**Last updated:** [May 25, 2021, 11:19am UTC](https://discourse.paraview.org/t/proposal-catalyst-v2-bidirectional-api/7258 "2021-05-25T11:19:51Z")

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The purpose of this post is to propose an API in order to drive a background simulation from ParaView graphical interface (GUI). The user wants to access random simulation parameters, then tweak the parameters and send …

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## [Catalyst 2.0: adding support for custom mesh blueprints](https://discourse.paraview.org/t/catalyst-2-0-adding-support-for-custom-mesh-blueprints/7283)

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**Author:** [@utkarsh.ayachit](https://discourse.paraview.org/u/utkarsh.ayachit)\
**Replies:** 4\
**Last updated:** [May 24, 2021, 8:47pm UTC](https://discourse.paraview.org/t/catalyst-2-0-adding-support-for-custom-mesh-blueprints/7283 "2021-05-24T20:47:17Z")

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I don’t have a specific question for the forum here, but more of a description of my current approach for implementing a new Catalyst adaptor. Figured I’ll share it with the broader community and see if people have any s…

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## [Disambiguating Catalyst API version 2.0 and Catalyst Python Script version 2.0](https://discourse.paraview.org/t/disambiguating-catalyst-api-version-2-0-and-catalyst-python-script-version-2-0/7266)

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**Author:** [@utkarsh.ayachit](https://discourse.paraview.org/u/utkarsh.ayachit)\
**Replies:** 5\
**Last updated:** [May 20, 2021, 10:03pm UTC](https://discourse.paraview.org/t/disambiguating-catalyst-api-version-2-0-and-catalyst-python-script-version-2-0/7266 "2021-05-20T22:03:18Z")

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This post is to discuss ideas for nomenclature to use when discussion the new Catalyst API that uses Conduit and the new way of writing Python scripts for Catalyst.

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## [Two new backgrounds](https://discourse.paraview.org/t/two-new-backgrounds/7144)

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**Author:** [@wascott](https://discourse.paraview.org/u/wascott)\
**Replies:** 19\
**Last updated:** [May 18, 2021, 4:46pm UTC](https://discourse.paraview.org/t/two-new-backgrounds/7144 "2021-05-18T16:46:22Z")

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Francesca and I have been discussing new backgrounds forever. At Francescas suggestion, I would like to propose two new backgrounds, both from the beige space. See attached screenshot and state file.

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## [MPI is not found by find\_library(ParaView) in v5.9 but it works in v5.8](https://discourse.paraview.org/t/mpi-is-not-found-by-find-library-paraview-in-v5-9-but-it-works-in-v5-8/7242)

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**Author:** [@lhofmann](https://discourse.paraview.org/u/lhofmann)\
**Replies:** 9\
**Last updated:** [May 18, 2021, 1:37pm UTC](https://discourse.paraview.org/t/mpi-is-not-found-by-find-library-paraview-in-v5-9-but-it-works-in-v5-8/7242 "2021-05-18T13:37:24Z")

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I’m building ParaView from source on a current Arch Linux. During build, MPI is found just fine, but calling find\_library(ParaView) results in error -- Could NOT find MPI\_CXX (missing: MPI\_CXX\_WORKS) CMake Error at /us…

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## [Promoting IceT module to its own independent Module](https://discourse.paraview.org/t/promoting-icet-module-to-its-own-independent-module/5151)

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**Author:** [@psandana](https://discourse.paraview.org/u/psandana)\
**Replies:** 4\
**Last updated:** [May 15, 2021, 9:25pm UTC](https://discourse.paraview.org/t/promoting-icet-module-to-its-own-independent-module/5151 "2021-05-15T21:25:19Z")

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Hi everyone, I’m a VTK user and I wanted to use IceT when I noticed that ParaView already uses this. But I do not want to depend on entire ParaView because of that. I noticed also there were plans to move IceT submodul…

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## [ParaView 5.8.0 - fatal error: vtkDemandDrivenPipeline: No such file or directory](https://discourse.paraview.org/t/paraview-5-8-0-fatal-error-vtkdemanddrivenpipeline-no-such-file-or-directory/5711)

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**Author:** [@penkod](https://discourse.paraview.org/u/penkod)\
**Replies:** 1\
**Last updated:** [May 15, 2021, 6:23pm UTC](https://discourse.paraview.org/t/paraview-5-8-0-fatal-error-vtkdemanddrivenpipeline-no-such-file-or-directory/5711 "2021-05-15T18:23:52Z")

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I am developing a plugin that uses vtkDemandDrivenPipeline and vtkStreamingDemandDrivenPipeline routines when loading the plugin in order to access and change the interface time steps, time range, etc. In ParaView 5.6.2 …

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## [Reading time from plt format exported by tecplot](https://discourse.paraview.org/t/reading-time-from-plt-format-exported-by-tecplot/7184)

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**Author:** [@Sasa\_Sasa](https://discourse.paraview.org/u/Sasa_Sasa)\
**Replies:** 0\
**Last updated:** [May 9, 2021, 9:07pm UTC](https://discourse.paraview.org/t/reading-time-from-plt-format-exported-by-tecplot/7184 "2021-05-09T21:07:16Z")

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Hello there, Is there any way in Paraview to automatically detect the “time” from the tecplot plt files? I am aware that this issue was discussed long time ago in the link below but I hope it is now possible. Thank you …

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## [PV 5.7.0-RC2 Aborts Upon Startup](https://discourse.paraview.org/t/pv-5-7-0-rc2-aborts-upon-startup/2533)

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**Author:** [@theodorebaltis](https://discourse.paraview.org/u/theodorebaltis)\
**Replies:** 8\
**Last updated:** [May 7, 2021, 12:32pm UTC](https://discourse.paraview.org/t/pv-5-7-0-rc2-aborts-upon-startup/2533 "2021-05-07T12:32:05Z")

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Hello, Trying to run the Linux binaries accessed through a remote server using X2GO “paraview --mesa-llvm” results in the following: ( 10.726s) \[paraview \]vtkXOpenGLRenderWindow.:296 ERR| vtkXOpenGLRenderWi…

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## [Using a c++ plugin on a Python Programmable Filter](https://discourse.paraview.org/t/using-a-c-plugin-on-a-python-programmable-filter/7154)

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**Author:** [@Felipe\_Bordeu](https://discourse.paraview.org/u/Felipe_Bordeu)\
**Replies:** 2\
**Last updated:** [May 6, 2021, 3:52pm UTC](https://discourse.paraview.org/t/using-a-c-plugin-on-a-python-programmable-filter/7154 "2021-05-06T15:52:09Z")

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hello, I have c++ plugin, compiled and working, this plugin has a reader and a filter. Now I want to use the c++ plugin filter inside a programmable filter but I don’t know how to create the vtk instance of my filter…

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## [How to display stream lines from 3D vector field with tvtk and Python](https://discourse.paraview.org/t/how-to-display-stream-lines-from-3d-vector-field-with-tvtk-and-python/7162)

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**Author:** [@randalljames](https://discourse.paraview.org/u/randalljames)\
**Replies:** 0\
**Last updated:** [May 6, 2021, 2:00pm UTC](https://discourse.paraview.org/t/how-to-display-stream-lines-from-3d-vector-field-with-tvtk-and-python/7162 "2021-05-06T14:00:15Z")

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Hi all, I am trying to visualize stream lines from 3D velocity fields in a format lets say 10x10x100x100x3 where I have ten time steps, ten slices, 100x100 pixels inplane resolution and 3 vector components for each voxel…

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## [Zoom Close To Data](https://discourse.paraview.org/t/zoom-close-to-data/5752)

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**Author:** [@LfxPaul](https://discourse.paraview.org/u/LfxPaul)\
**Replies:** 24\
**Last updated:** [May 5, 2021, 5:03pm UTC](https://discourse.paraview.org/t/zoom-close-to-data/5752 "2021-05-05T17:03:50Z")

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This post is here to talk about a new button to zoom close to the active data. The already existing “Zoom To Data” button computes the camera distance as a constant that depends on the radius of the bounding box. The pr…

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## [GridConnectivity: does anyone use it?](https://discourse.paraview.org/t/gridconnectivity-does-anyone-use-it/7131)

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**Author:** [@utkarsh.ayachit](https://discourse.paraview.org/u/utkarsh.ayachit)\
**Replies:** 6\
**Last updated:** [May 3, 2021, 4:02pm UTC](https://discourse.paraview.org/t/gridconnectivity-does-anyone-use-it/7131 "2021-05-03T16:02:47Z")

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Does anyone use the Grid Connectivity filter in ParaView? The filter does not support paritioned dataset collections right now. I am trying to evaluate if its worth fixing it. Looking at the implementation its not entire…

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## [Added normal vector become useless from paraview 5.9](https://discourse.paraview.org/t/added-normal-vector-become-useless-from-paraview-5-9/6989)

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**Author:** [@sharon](https://discourse.paraview.org/u/sharon)\
**Replies:** 12\
**Last updated:** [April 28, 2021, 10:40am UTC](https://discourse.paraview.org/t/added-normal-vector-become-useless-from-paraview-5-9/6989 "2021-04-28T10:40:50Z")

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Dear Experts, I found my sphere become not such smooth after upgrade into paraview 5.9 i created my own sphere and calculated its normal vector, which works good in paraview 5.8, but after upgrade to paraview 5.9 it be…

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## [Proposal: replacing UserVoice with GitLab issues for feature requests](https://discourse.paraview.org/t/proposal-replacing-uservoice-with-gitlab-issues-for-feature-requests/6844)

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**Author:** [@cory.quammen](https://discourse.paraview.org/u/cory.quammen)\
**Replies:** 23\
**Last updated:** [April 26, 2021, 2:07pm UTC](https://discourse.paraview.org/t/proposal-replacing-uservoice-with-gitlab-issues-for-feature-requests/6844 "2021-04-26T14:07:02Z")

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Dear ParaView community, For years, we have had the ParaView User Voice for tracking popular feature requests for ParaView. The site is difficult to administer, it is not often checked, and there has recently been a sur…

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## [Fortran/C MPI interface for online picture savings](https://discourse.paraview.org/t/fortran-c-mpi-interface-for-online-picture-savings/6972)

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**Author:** [@rw31415](https://discourse.paraview.org/u/rw31415)\
**Replies:** 2\
**Last updated:** [April 20, 2021, 7:17am UTC](https://discourse.paraview.org/t/fortran-c-mpi-interface-for-online-picture-savings/6972 "2021-04-20T07:17:06Z")

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Hello, I’ve been using Paraview for a little while and I love it. So much that I would love to embark it in my code :slight\_smile: I’m running very computationaly expensive simulations of 3d hydrodynamics using Fortran…

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## [Automatically load python plugin in paraview 5.6 based application](https://discourse.paraview.org/t/automatically-load-python-plugin-in-paraview-5-6-based-application/6954)

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**Author:** [@lvauchier](https://discourse.paraview.org/u/lvauchier)\
**Replies:** 0\
**Last updated:** [April 14, 2021, 3:44pm UTC](https://discourse.paraview.org/t/automatically-load-python-plugin-in-paraview-5-6-based-application/6954 "2021-04-14T15:44:56Z")

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Hello, As part of the development of LidarView (currently based on Paraview 5.6), we would like to integrate new functionnalities to our application via plugins that are implemented in python (using VTKPythonAlgorithmBa…

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## [setting doublevector label dynamically in VTKPythonAlgorithmBase](https://discourse.paraview.org/t/setting-doublevector-label-dynamically-in-vtkpythonalgorithmbase/6934)

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**Author:** [@Felipe\_Bordeu](https://discourse.paraview.org/u/Felipe_Bordeu)\
**Replies:** 3\
**Last updated:** [April 12, 2021, 2:59pm UTC](https://discourse.paraview.org/t/setting-doublevector-label-dynamically-in-vtkpythonalgorithmbase/6934 "2021-04-12T14:59:02Z")

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Hello, I have a prototype reader using VTKPythonAlgorithmBase, I’m able to set the range of a doublevector property dynamically (using an auxiliary function with a specific xml). But can I set the name of the slider dyn…

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## [implementing CanReadFile in a VTKPythonAlgorithmBase](https://discourse.paraview.org/t/implementing-canreadfile-in-a-vtkpythonalgorithmbase/6933)

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**Author:** [@Felipe\_Bordeu](https://discourse.paraview.org/u/Felipe_Bordeu)\
**Replies:** 5\
**Last updated:** [April 12, 2021, 2:29pm UTC](https://discourse.paraview.org/t/implementing-canreadfile-in-a-vtkpythonalgorithmbase/6933 "2021-04-12T14:29:21Z")

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Hello, I using VTKPythonAlgorithmBase to prototype a reader. I implemented the CanReadFile function in python but I’m unable make ParaView use it. I have 2 reader using the same extension, but only one return 1 in the f…

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## [The Clip result is not right](https://discourse.paraview.org/t/the-clip-result-is-not-right/6881)

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**Author:** [@gangyi\_rao](https://discourse.paraview.org/u/gangyi_rao)\
**Replies:** 23\
**Last updated:** [April 6, 2021, 12:59pm UTC](https://discourse.paraview.org/t/the-clip-result-is-not-right/6881 "2021-04-06T12:59:52Z")

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Hi Experts, When I display the clip use paraview. I found that the clip field result has big difference whith the origin field result. Is it the color interpolation error? I upload the clip image and result image Th…

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## [How to set the default value for a proxy property?](https://discourse.paraview.org/t/how-to-set-the-default-value-for-a-proxy-property/6788)

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**Author:** [@HollowSun0](https://discourse.paraview.org/u/HollowSun0)\
**Replies:** 5\
**Last updated:** [April 1, 2021, 11:39pm UTC](https://discourse.paraview.org/t/how-to-set-the-default-value-for-a-proxy-property/6788 "2021-04-01T23:39:57Z")

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Dear all, I’m having trouble adding a proxy property to an existing source proxy. On Paraview 5.7, after loading an already existing state file containing a source proxy instance, selecting the instance shows an empty …

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## [ParaView 5.9 and minimum/recommended QT version](https://discourse.paraview.org/t/paraview-5-9-and-minimum-recommended-qt-version/5333)

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**Author:** [@utkarsh.ayachit](https://discourse.paraview.org/u/utkarsh.ayachit)\
**Replies:** 11\
**Last updated:** [March 31, 2021, 4:22pm UTC](https://discourse.paraview.org/t/paraview-5-9-and-minimum-recommended-qt-version/5333 "2021-03-31T16:22:19Z")

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With Qt 5.15 LTS being out since May, it’s probably time to update the QT versions required by ParaView as follows: minimum Qt version: 5.12 LTS recommended Qt version: 5.15 LTS binaries to be built with Qt version 5.1…

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