# ParaView Support

**URL:** https://discourse.paraview.org/c/paraview-support/7.md?page=20

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**Page:** 21

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## [In CFD, there are streamlines and streamtubes. What is a stream surface like?](https://discourse.paraview.org/t/in-cfd-there-are-streamlines-and-streamtubes-what-is-a-stream-surface-like/16374)

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**Author:** [@hdz19900725](https://discourse.paraview.org/u/hdz19900725)\
**Replies:** 3\
**Last updated:** [March 25, 2025, 8:20am UTC](https://discourse.paraview.org/t/in-cfd-there-are-streamlines-and-streamtubes-what-is-a-stream-surface-like/16374 "2025-03-25T08:20:42Z")

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In CFD, there are streamlines and streamtubes. What is a stream surface like?

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## [Pvpython for paraview 5.13 and python3.10.12 gives me segmentation fault](https://discourse.paraview.org/t/pvpython-for-paraview-5-13-and-python3-10-12-gives-me-segmentation-fault/16349)

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**Author:** [@RaniaYian](https://discourse.paraview.org/u/RaniaYian)\
**Replies:** 12\
**Last updated:** [March 24, 2025, 11:33am UTC](https://discourse.paraview.org/t/pvpython-for-paraview-5-13-and-python3-10-12-gives-me-segmentation-fault/16349 "2025-03-24T11:33:02Z")

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Hi all, I am trying to automate a process for many .vtk files. The problem is that I cannot make my script work since when i run pvpython myscript.py from terminal, the line from paraview.simple import \* gives m…

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## [Paraview with EGL problem](https://discourse.paraview.org/t/paraview-with-egl-problem/7601)

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**Author:** [@Luis\_Carlos\_Carneiro](https://discourse.paraview.org/u/Luis_Carlos_Carneiro)\
**Replies:** 6\
**Last updated:** [March 24, 2025, 10:59am UTC](https://discourse.paraview.org/t/paraview-with-egl-problem/7601 "2025-03-24T10:59:51Z")

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Dear All, 1st Headless server with K80. CUDA 11.3 2nd Paraview with EGL 3rd Paraview Python run in a Client window of VNCServer (on server) gives the following error: /home/luis\_goncalves/Downloads/ParaView-5.9.1-eg…

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## [Imported FDS data (either PLOT3D or .SMV) in Paraview and exporting to read it either in MATLAB or Python](https://discourse.paraview.org/t/imported-fds-data-either-plot3d-or-smv-in-paraview-and-exporting-to-read-it-either-in-matlab-or-python/16364)

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**Author:** [@sagarsinghal](https://discourse.paraview.org/u/sagarsinghal)\
**Replies:** 1\
**Last updated:** [March 24, 2025, 10:43am UTC](https://discourse.paraview.org/t/imported-fds-data-either-plot3d-or-smv-in-paraview-and-exporting-to-read-it-either-in-matlab-or-python/16364 "2025-03-24T10:43:01Z")

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Hi, I have time series data of 2D slices and PLOT3D data generated from FDS. I am able to load it in Paraview. However, I wish to further post-process the data field either in MATLAB or Python. I tried to export the dat…

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## [Slow Transient Load (~1.6m cells)](https://discourse.paraview.org/t/slow-transient-load-1-6m-cells/16351)

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**Author:** [@fatihmtlm](https://discourse.paraview.org/u/fatihmtlm)\
**Replies:** 6\
**Last updated:** [March 24, 2025, 8:46am UTC](https://discourse.paraview.org/t/slow-transient-load-1-6m-cells/16351 "2025-03-24T08:46:43Z")

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Hi, I have external flow result files originally in Ensight Gold format, containing around 1.6 million polyhedral cells. I’ve tried multiple formats like .vtu, .pvtu, and of course Ensight Gold, but the loading time for …

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## [Video streaming in ParaView (or even VTK)](https://discourse.paraview.org/t/video-streaming-in-paraview-or-even-vtk/16251)

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**Author:** [@wsherman](https://discourse.paraview.org/u/wsherman)\
**Replies:** 7\
**Last updated:** [March 24, 2025, 7:44am UTC](https://discourse.paraview.org/t/video-streaming-in-paraview-or-even-vtk/16251 "2025-03-24T07:44:02Z")

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Perhaps an off-the-wall question, and maybe will all the other Kitware options available not one worth pursuing, but I wonder if there might be an existing workflow for video streaming the ParaView rendering using RTP or…

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## [difference between points](https://discourse.paraview.org/t/difference-between-points/16357)

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**Author:** [@FredrikR](https://discourse.paraview.org/u/FredrikR)\
**Replies:** 2\
**Last updated:** [March 22, 2025, 7:44am UTC](https://discourse.paraview.org/t/difference-between-points/16357 "2025-03-22T07:44:35Z")

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Hi! I have a mesh with data points showing displacement. I would like to plot the displacement difference between 2 points over time. Any suggestions? Best regards Fredrik

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## [Flow visualization.(Forward/Backward)](https://discourse.paraview.org/t/flow-visualization-forward-backward/16344)

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**Author:** [@secret5514](https://discourse.paraview.org/u/secret5514)\
**Replies:** 10\
**Last updated:** [March 19, 2025, 12:33am UTC](https://discourse.paraview.org/t/flow-visualization-forward-backward/16344 "2025-03-19T00:33:14Z")

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Hello, I have been using ParaView for three months. I am currently loading an Ensight file and working on the visualization of the aorta, the forward and backward flow. I separated and visualized the forward and bac…

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## [Can a Python plugin access Paraview's progress bar?](https://discourse.paraview.org/t/can-a-python-plugin-access-paraviews-progress-bar/16352)

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**Author:** [@florezg](https://discourse.paraview.org/u/florezg)\
**Replies:** 2\
**Last updated:** [March 19, 2025, 4:29am UTC](https://discourse.paraview.org/t/can-a-python-plugin-access-paraviews-progress-bar/16352 "2025-03-19T04:29:08Z")

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Is there a way for a plugin, i.e., a class that inherits from “VTKPythonAlgorithmBase” to access Paraview’s (status bar) progress bar widget. The class vtkAlgorithm has the methods “SetProgressShiftScale”, “SetProgressTe…

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## [Problem visualizing VTK HDF file](https://discourse.paraview.org/t/problem-visualizing-vtk-hdf-file/16308)

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**Author:** [@Suman\_Vajjala](https://discourse.paraview.org/u/Suman_Vajjala)\
**Replies:** 12\
**Last updated:** [March 18, 2025, 4:00pm UTC](https://discourse.paraview.org/t/problem-visualizing-vtk-hdf-file/16308 "2025-03-18T16:00:02Z")

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Hi. I have developed a code which writes a VTKHDF file. I have visualized the file when it is generated using 20/30 cores. However, with 420 cores, paraview takes a lot of time and even then I am unable to visualize my f…

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## [Installing Paraview in headless/Offscreen mode using Spack](https://discourse.paraview.org/t/installing-paraview-in-headless-offscreen-mode-using-spack/16347)

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**Author:** [@uturuncoglu](https://discourse.paraview.org/u/uturuncoglu)\
**Replies:** 2\
**Last updated:** [March 17, 2025, 7:51pm UTC](https://discourse.paraview.org/t/installing-paraview-in-headless-offscreen-mode-using-spack/16347 "2025-03-17T19:51:19Z")

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Hi, I am trying to install ParaView to HPC platform in headless mode with spack without no luck. At this point I am using following command in spack side, spack install paraview@5.13.1%oneapi@2024.2.1+libcatalyst+fortr…

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## [How to convert/export vtk unstructured grid file to step file format](https://discourse.paraview.org/t/how-to-convert-export-vtk-unstructured-grid-file-to-step-file-format/15200)

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**Author:** [@anoopng](https://discourse.paraview.org/u/anoopng)\
**Replies:** 3\
**Last updated:** [March 17, 2025, 8:07am UTC](https://discourse.paraview.org/t/how-to-convert-export-vtk-unstructured-grid-file-to-step-file-format/15200 "2025-03-17T08:07:58Z")

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Hey! I just wanted to know how to convert/export vtk unstructured grid to step file format. I have a topology optimization results in vtk unstructured grid format and want those files in step file is there a way to do …

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## [Opacity problem when overlapping several planes with transparency](https://discourse.paraview.org/t/opacity-problem-when-overlapping-several-planes-with-transparency/16342)

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**Author:** [@Captain\_Convergence](https://discourse.paraview.org/u/Captain_Convergence)\
**Replies:** 4\
**Last updated:** [March 16, 2025, 8:28am UTC](https://discourse.paraview.org/t/opacity-problem-when-overlapping-several-planes-with-transparency/16342 "2025-03-16T08:28:24Z")

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Dear support, I am trying to display some planes where I used opacity mapping to cut the visible fields. As you can see in the image below there is a visualization problem when several planes overlap: The problem do…

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## [Cartesian Coordinate to Cylindrical Coordinate](https://discourse.paraview.org/t/cartesian-coordinate-to-cylindrical-coordinate/13590)

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**Author:** [@Nithin\_Veerendranath](https://discourse.paraview.org/u/Nithin_Veerendranath)\
**Replies:** 3\
**Last updated:** [March 15, 2025, 4:15pm UTC](https://discourse.paraview.org/t/cartesian-coordinate-to-cylindrical-coordinate/13590 "2025-03-15T16:15:51Z")

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Hi, I have my stress tensor data file with (x, y, z) cartesian coordinate system and components as xx, xy, xz, yx, yy and so on the 9 components in it. Now I want to have it in Cylindrical coordinate system. I have see…

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## [Linking animation frames to time series data (hdf5, numpy) in Python reader plugin](https://discourse.paraview.org/t/linking-animation-frames-to-time-series-data-hdf5-numpy-in-python-reader-plugin/16337)

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**Author:** [@rbrooksher](https://discourse.paraview.org/u/rbrooksher)\
**Replies:** 1\
**Last updated:** [March 15, 2025, 1:48pm UTC](https://discourse.paraview.org/t/linking-animation-frames-to-time-series-data-hdf5-numpy-in-python-reader-plugin/16337 "2025-03-15T13:48:12Z")

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Hello, I have been attempting to create a reader plugin for my hdf5 dataset. The problem I am facing is that animation frames are consistently showing as the default, 10 steps between 1 and 10 inclusive. Is this expecte…

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## [programmable script - python bug, wrong results?](https://discourse.paraview.org/t/programmable-script-python-bug-wrong-results/16300)

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**Author:** [@Dave1](https://discourse.paraview.org/u/Dave1)\
**Replies:** 4\
**Last updated:** [March 14, 2025, 6:49pm UTC](https://discourse.paraview.org/t/programmable-script-python-bug-wrong-results/16300 "2025-03-14T18:49:20Z")

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Hi I have a simple programmable script with a condition where i use np.where. The velocity for example should be smaller than 1 otherwise it should be nan. VEL = np.where((VEL \>= 0) & (VEL \<= 1.0), VEL, np.nan)) When…

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## [vtkBlockColors vs Block id](https://discourse.paraview.org/t/vtkblockcolors-vs-block-id/16326)

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**Author:** [@Hemiao\_Zhang](https://discourse.paraview.org/u/Hemiao_Zhang)\
**Replies:** 2\
**Last updated:** [March 14, 2025, 6:13pm UTC](https://discourse.paraview.org/t/vtkblockcolors-vs-block-id/16326 "2025-03-14T18:13:12Z")

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Hi Paraview community, I am wondering what is the difference between the numbering in vtkBlock and Block from the properties panel. For instance, in the screenshot attached, why are the numberings from \`vtkBlockColors’ …

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## [Paraview 5.10.1 doesn't load XML .vtp file correctly](https://discourse.paraview.org/t/paraview-5-10-1-doesnt-load-xml-vtp-file-correctly/16328)

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**Author:** [@DeadComposer](https://discourse.paraview.org/u/DeadComposer)\
**Replies:** 3\
**Last updated:** [March 14, 2025, 12:44pm UTC](https://discourse.paraview.org/t/paraview-5-10-1-doesnt-load-xml-vtp-file-correctly/16328 "2025-03-14T12:44:23Z")

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Paraview 5.10.1 doesn’t load XML-format .vtp file correctly The contents of my XML-format .vtp file are below. Paraview 5.10.1 loads this but only adds 1 rectangle to the viewing area, even though there are 2 rectangle…

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## [Automatically loading window arrangements on startup](https://discourse.paraview.org/t/automatically-loading-window-arrangements-on-startup/16331)

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**Author:** [@learex](https://discourse.paraview.org/u/learex)\
**Replies:** 4\
**Last updated:** [March 14, 2025, 12:19pm UTC](https://discourse.paraview.org/t/automatically-loading-window-arrangements-on-startup/16331 "2025-03-14T12:19:54Z")

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When starting paraview, it is not possible to automatically load a .pwin file. Detached panels do not load “as last used layout” (using Ubuntu), hence manually opening the arrangement is necessary every time when opening…

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## [how to output field data from paraview (should be easy)](https://discourse.paraview.org/t/how-to-output-field-data-from-paraview-should-be-easy/15324)

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**Author:** [@jackeggemeyer](https://discourse.paraview.org/u/jackeggemeyer)\
**Replies:** 7\
**Last updated:** [March 14, 2025, 11:55am UTC](https://discourse.paraview.org/t/how-to-output-field-data-from-paraview-should-be-easy/15324 "2025-03-14T11:55:39Z")

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I want to output my field data, the data that has one value per time step, like how many nucleations occurred or degrees of freedom. I don’t need them in the same file as other types of data, I just need this to be outpu…

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## [Add text source from file (Billboard or Flagpole mode)](https://discourse.paraview.org/t/add-text-source-from-file-billboard-or-flagpole-mode/16059)

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**Author:** [@marios\_geo](https://discourse.paraview.org/u/marios_geo)\
**Replies:** 3\
**Last updated:** [March 14, 2025, 9:39am UTC](https://discourse.paraview.org/t/add-text-source-from-file-billboard-or-flagpole-mode/16059 "2025-03-14T09:39:11Z")

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Hi, I can create a text source that is “fixed” on a xyz location, by using the Sources → Text and add the xyz manually (both Billboard and/or Flagpole). Yet, I have about 1000 text objects I would like to add, all of …

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## [Extracting data from a parametric case from single slice](https://discourse.paraview.org/t/extracting-data-from-a-parametric-case-from-single-slice/16320)

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**Author:** [@Rishab\_Kannamvar](https://discourse.paraview.org/u/Rishab_Kannamvar)\
**Replies:** 0\
**Last updated:** [March 13, 2025, 10:51am UTC](https://discourse.paraview.org/t/extracting-data-from-a-parametric-case-from-single-slice/16320 "2025-03-13T10:51:51Z")

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Hi, I have a set of simulations for a pump, which i do for a range of impeller speeds. I simulated 10 cases of the same pump and mesh for different impeller speeds. I picked one RPM case, extracted my domain of interest…

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## [Too dark water material when rendering](https://discourse.paraview.org/t/too-dark-water-material-when-rendering/16316)

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**Author:** [@Kompe](https://discourse.paraview.org/u/Kompe)\
**Replies:** 5\
**Last updated:** [March 13, 2025, 2:22pm UTC](https://discourse.paraview.org/t/too-dark-water-material-when-rendering/16316 "2025-03-13T14:22:18Z")

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Good day, everyone. I’m starting to learn about the raytracing and rendering possibilities in ParaView to make my OpenFOAM results prettier. They usually involve water and free surfaces for my part, so to have a sort of…

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## [Method to Sequentially Play a Group of VTK Files Without Time Array in ParaView](https://discourse.paraview.org/t/method-to-sequentially-play-a-group-of-vtk-files-without-time-array-in-paraview/16265)

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**Author:** [@Qwenthur](https://discourse.paraview.org/u/Qwenthur)\
**Replies:** 6\
**Last updated:** [March 13, 2025, 9:47am UTC](https://discourse.paraview.org/t/method-to-sequentially-play-a-group-of-vtk-files-without-time-array-in-paraview/16265 "2025-03-13T09:47:28Z")

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Hi all, After loading a group of VTK files generated by mumax3 into ParaView, I am unsure how to play these files sequentially as none of them contain a time array. My objective is to play them in order according to the…

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## [After make a slice animation, export data from specific time step](https://discourse.paraview.org/t/after-make-a-slice-animation-export-data-from-specific-time-step/16290)

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**Author:** [@tjwldhks79](https://discourse.paraview.org/u/tjwldhks79)\
**Replies:** 6\
**Last updated:** [March 13, 2025, 1:45am UTC](https://discourse.paraview.org/t/after-make-a-slice-animation-export-data-from-specific-time-step/16290 "2025-03-13T01:45:11Z")

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I have set up a movie to follow the y-axis at a specific time step. (I have a transient result) With this setup, instead of following the time index in the bottom left corner, the movie follows the number of frames I sp…

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## [Accessing virtual environment within Paraview](https://discourse.paraview.org/t/accessing-virtual-environment-within-paraview/16295)

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**Author:** [@mcgoldba](https://discourse.paraview.org/u/mcgoldba)\
**Replies:** 3\
**Last updated:** [March 12, 2025, 10:52pm UTC](https://discourse.paraview.org/t/accessing-virtual-environment-within-paraview/16295 "2025-03-12T22:52:40Z")

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I am attempting to access a virtual environment within paraview as described here: Using Python Virtual environments in ParaView 5.13.0 However, when I try to start paraview with paraview --venv .venv/, The paraview in…

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## [Different results in Paraview and CFDPost from same fluent data](https://discourse.paraview.org/t/different-results-in-paraview-and-cfdpost-from-same-fluent-data/16293)

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**Author:** [@scabo](https://discourse.paraview.org/u/scabo)\
**Replies:** 25\
**Last updated:** [March 12, 2025, 4:00pm UTC](https://discourse.paraview.org/t/different-results-in-paraview-and-cfdpost-from-same-fluent-data/16293 "2025-03-12T16:00:23Z")

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Hi. I have some fluent data and i exported them in gold-ensight format and opened in Paraview. But I am getting different contour plots for velocity in Paraview and CFDPost. The one in CFDPost matches with the literature…

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## [How is the Q criterion calculated?](https://discourse.paraview.org/t/how-is-the-q-criterion-calculated/16299)

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**Author:** [@Pedro](https://discourse.paraview.org/u/Pedro)\
**Replies:** 0\
**Last updated:** [March 11, 2025, 6:58pm UTC](https://discourse.paraview.org/t/how-is-the-q-criterion-calculated/16299 "2025-03-11T18:58:39Z")

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When using a gradient filter to calculate the Q criterion, what are the steps Paraview goes throught when calculating it? Does it interpolate in order to find values intermediate to points for example? Or what mathod doe…

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## [Converting Fluent results into Paraview](https://discourse.paraview.org/t/converting-fluent-results-into-paraview/16288)

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**Author:** [@scabo](https://discourse.paraview.org/u/scabo)\
**Replies:** 3\
**Last updated:** [March 11, 2025, 4:55pm UTC](https://discourse.paraview.org/t/converting-fluent-results-into-paraview/16288 "2025-03-11T16:55:09Z")

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I have got some Fluent results, I want to view in Paraview. I am exporting in ensight-gold format but after opening the encas file in paraview, it is not showing the boundaries, like wall, inlet, outlet, etc, in paraview…

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## [How to cull backface triangles](https://discourse.paraview.org/t/how-to-cull-backface-triangles/16297)

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**Author:** [@Michael\_Jackson](https://discourse.paraview.org/u/Michael_Jackson)\
**Replies:** 2\
**Last updated:** [March 11, 2025, 2:29pm UTC](https://discourse.paraview.org/t/how-to-cull-backface-triangles/16297 "2025-03-11T14:29:30Z")

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I have an STL File that I know has inconsistent triangle windings. How do I entice ParaView to NOT show those triangles? It’s been a while but isn’t it something about backface culling or something like that?

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