# Development

**URL:** https://discourse.vtk.org/c/development/7.md?page=3

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

**Page:** 4

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## [Possible VTK 9.6.0rc2 regression with ghost cell rendering](https://discourse.vtk.org/t/possible-vtk-9-6-0rc2-regression-with-ghost-cell-rendering/16251)

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**Author:** [@user27182](https://discourse.vtk.org/u/user27182)\
**Replies:** 16\
**Last updated:** [January 26, 2026, 8:26pm UTC](https://discourse.vtk.org/t/possible-vtk-9-6-0rc2-regression-with-ghost-cell-rendering/16251 "2026-01-26T20:26:22Z")

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ugrid.vtu (4.4 KB) I have attached an UnstructuredGrid mesh file with a 'vtkGhostType' cell array. The top “row” of cells in the dataset are masked. Using the code below with vtk==9.5.20250802.dev0, we get : But wi…

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## [Fresh gitlab commands for developers](https://discourse.vtk.org/t/fresh-gitlab-commands-for-developers/16240)

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**Author:** [@dgobbi](https://discourse.vtk.org/u/dgobbi)\
**Replies:** 0\
**Last updated:** [January 17, 2026, 3:23pm UTC](https://discourse.vtk.org/t/fresh-gitlab-commands-for-developers/16240 "2026-01-17T15:23:35Z")

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This applies to the VTK master branch and the upcoming 9.6.0 release. All VTK developers are familiar with git gitlab-push, but VTK also provides some other gitlab CLI commands (some only recently added) which can impro…

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## [VTK/Paraview Gitlab "Merge requests" page error in Firefox](https://discourse.vtk.org/t/vtk-paraview-gitlab-merge-requests-page-error-in-firefox/16236)

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**Author:** [@hakostra](https://discourse.vtk.org/u/hakostra)\
**Replies:** 3\
**Last updated:** [January 16, 2026, 8:16am UTC](https://discourse.vtk.org/t/vtk-paraview-gitlab-merge-requests-page-error-in-firefox/16236 "2026-01-16T08:16:06Z")

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Lately, the “Merge requests” page in both VTK and Paraview Gitlab has been showing just an error “An error occurred while loading merge requests” in Firefox on Linux (have not tried Windows). With Chromium it works just …

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## [Adding some ParaView colors to vtkNamedColors](https://discourse.vtk.org/t/adding-some-paraview-colors-to-vtknamedcolors/16220)

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**Author:** [@amaclean](https://discourse.vtk.org/u/amaclean)\
**Replies:** 7\
**Last updated:** [January 14, 2026, 9:15pm UTC](https://discourse.vtk.org/t/adding-some-paraview-colors-to-vtknamedcolors/16220 "2026-01-14T21:15:57Z")

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ParaView has two nicely balanced and really useful background colors that now appear quite a lot in the VTK Examples, namely ParaViewBlueGrayBkg and ParaViewWarmGrayBkg. What do people think about adding these colors to…

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## [Support PLY with texture coordinates parameters named (s, t)](https://discourse.vtk.org/t/support-ply-with-texture-coordinates-parameters-named-s-t/16197)

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**Author:** [@afavray.modjaw](https://discourse.vtk.org/u/afavray.modjaw)\
**Replies:** 7\
**Last updated:** [January 14, 2026, 11:14am UTC](https://discourse.vtk.org/t/support-ply-with-texture-coordinates-parameters-named-s-t/16197 "2026-01-14T11:14:33Z")

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Hello, I am using vtkPLYReader to import various PLY meshes in my project (python VTK 9.5.2). I have a problem with some PLY file formats that use external texture : the vtkPLYReader fails to parse texture coordinates …

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## [Wrong orientation of principal vector generated by vtkTensorPrincipalInvariants](https://discourse.vtk.org/t/wrong-orientation-of-principal-vector-generated-by-vtktensorprincipalinvariants/16218)

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**Author:** [@npoletz](https://discourse.vtk.org/u/npoletz)\
**Replies:** 2\
**Last updated:** [January 12, 2026, 9:26am UTC](https://discourse.vtk.org/t/wrong-orientation-of-principal-vector-generated-by-vtktensorprincipalinvariants/16218 "2026-01-12T09:26:36Z")

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Hello, I believe there is an error in the principal vector orientations produced by vtkTensorPrincipalInvariants. In the image below, the diagonal tensor \[1, 2, 3\] (left) and its version rotated counterclockwise by π/6…

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## [Support export of PLY with external texture](https://discourse.vtk.org/t/support-export-of-ply-with-external-texture/16198)

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**Author:** [@afavray.modjaw](https://discourse.vtk.org/u/afavray.modjaw)\
**Replies:** 2\
**Last updated:** [January 8, 2026, 3:29pm UTC](https://discourse.vtk.org/t/support-export-of-ply-with-external-texture/16198 "2026-01-08T15:29:19Z")

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Hello, I am using vtkPLYReader + vtkPLYWriter to import/export various PLY meshes in my project (python VTK 9.5.2). I have a problem with some PLY file formats that use external texture : the vtkPLYWriter doesn’t write…

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## [vtkChartXY log scale is not working - possible bug](https://discourse.vtk.org/t/vtkchartxy-log-scale-is-not-working-possible-bug/14085)

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**Author:** [@eduardo.camargo](https://discourse.vtk.org/u/eduardo.camargo)\
**Replies:** 5\
**Last updated:** [December 22, 2025, 11:52pm UTC](https://discourse.vtk.org/t/vtkchartxy-log-scale-is-not-working-possible-bug/14085 "2025-12-22T23:52:02Z")

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Hello, everyone! We use VTK on several projects in my company and recently, during an upgrade from VTK-6.3.0 to VTK-9.3.0, a bug was found. I have already debugged the VTK source hoping that I could find a fix for it bu…

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## [How does the VTKHDF reader handle HDF5 hardlink datasets?](https://discourse.vtk.org/t/how-does-the-vtkhdf-reader-handle-hdf5-hardlink-datasets/16189)

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**Author:** [@nncarlson](https://discourse.vtk.org/u/nncarlson)\
**Replies:** 6\
**Last updated:** [December 19, 2025, 9:47am UTC](https://discourse.vtk.org/t/how-does-the-vtkhdf-reader-handle-hdf5-hardlink-datasets/16189 "2025-12-19T09:47:24Z")

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I’d like to know how the VTKHDF reader handles a dataset that is an HDF5 hardlink to another dataset. Is it smart enough to only load the dataset into memory once and reuse that reference each time it encounters a hardli…

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## [Display strange lines(dashed) when I zoom in](https://discourse.vtk.org/t/display-strange-lines-dashed-when-i-zoom-in/16176)

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**Author:** [@cmodel](https://discourse.vtk.org/u/cmodel)\
**Replies:** 10\
**Last updated:** [December 16, 2025, 3:45pm UTC](https://discourse.vtk.org/t/display-strange-lines-dashed-when-i-zoom-in/16176 "2025-12-16T15:45:18Z")

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Hello, I have met one strange problem, I have the rendererd image in display area, when I zoom in with mouse, it gradually display some strange lines, more zoomed-in(closer), more clearer the dashed lines. But I have no…

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## [VTK with PCL not working as expected with migration to qt6 QVTKWidget to QVTKOpenGLNativeWidget](https://discourse.vtk.org/t/vtk-with-pcl-not-working-as-expected-with-migration-to-qt6-qvtkwidget-to-qvtkopenglnativewidget/16182)

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**Author:** [@Adi](https://discourse.vtk.org/u/Adi)\
**Replies:** 0\
**Last updated:** [December 15, 2025, 8:44am UTC](https://discourse.vtk.org/t/vtk-with-pcl-not-working-as-expected-with-migration-to-qt6-qvtkwidget-to-qvtkopenglnativewidget/16182 "2025-12-15T08:44:39Z")

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Hello guys , I am migrating a desktop based application from qt 5 to qt 6 which includes following libraries PCL VTK Qt Due to deprication and compatible issues I was forced to upgrade VTK and PCL to VTK 9.1 and PCL…

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## [Important Update: Standard iostream availability from VTK](https://discourse.vtk.org/t/important-update-standard-iostream-availability-from-vtk/16171)

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**Author:** [@sankhesh](https://discourse.vtk.org/u/sankhesh)\
**Replies:** 0\
**Last updated:** [December 3, 2025, 3:07pm UTC](https://discourse.vtk.org/t/important-update-standard-iostream-availability-from-vtk/16171 "2025-12-03T15:07:57Z")

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Please note a significant change in VTK. In the changeset from Merge Request !11993, the inclusion of \<iostream\> has been removed from a core header. This change previously caused global constructors to be triggered in …

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## [How to connect unordered points by nearest neighbors without forming a loop?](https://discourse.vtk.org/t/how-to-connect-unordered-points-by-nearest-neighbors-without-forming-a-loop/16165)

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**Author:** [@KSJ](https://discourse.vtk.org/u/KSJ)\
**Replies:** 1\
**Last updated:** [November 28, 2025, 1:29pm UTC](https://discourse.vtk.org/t/how-to-connect-unordered-points-by-nearest-neighbors-without-forming-a-loop/16165 "2025-11-28T13:29:30Z")

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I am trying to build a vtkPolyLine from a set of unordered 3D points. My goal is to connect the points based on nearest neighbors, not based on the input index order. I need the result to be one open polyline, not a clo…

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## [Counter-intuitive results for min/max spatial dimension of a data set](https://discourse.vtk.org/t/counter-intuitive-results-for-min-max-spatial-dimension-of-a-data-set/16159)

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**Author:** [@user27182](https://discourse.vtk.org/u/user27182)\
**Replies:** 3\
**Last updated:** [November 26, 2025, 4:53am UTC](https://discourse.vtk.org/t/counter-intuitive-results-for-min-max-spatial-dimension-of-a-data-set/16159 "2025-11-26T04:53:10Z")

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I tried using the new GetMinSpatialDimension/GetMaxSpatialDimension members from VTK 9.5, but it returns results that seem counter-intuitive. E.g. for datasets without cells, the following prints (3, 0) as the min/max sp…

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## [\[Coincident Topology\] backside lines blink when "PolygonOffset" is set](https://discourse.vtk.org/t/coincident-topology-backside-lines-blink-when-polygonoffset-is-set/16158)

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**Author:** [@a-ciue](https://discourse.vtk.org/u/a-ciue)\
**Replies:** 0\
**Last updated:** [November 25, 2025, 10:50am UTC](https://discourse.vtk.org/t/coincident-topology-backside-lines-blink-when-polygonoffset-is-set/16158 "2025-11-25T10:50:57Z")

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Hi, I have a polydata with polys and lines. Some part of lines is behind the polys and they are covered by polys. I found and activated the “PolygonOffset” coincident topology. The “covered” issue is unsolved and I enco…

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## [Looking for guidance on writing python unit tests using python vtk](https://discourse.vtk.org/t/looking-for-guidance-on-writing-python-unit-tests-using-python-vtk/16148)

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**Author:** [@Dan\_The\_Man](https://discourse.vtk.org/u/Dan_The_Man)\
**Replies:** 8\
**Last updated:** [November 24, 2025, 5:03pm UTC](https://discourse.vtk.org/t/looking-for-guidance-on-writing-python-unit-tests-using-python-vtk/16148 "2025-11-24T17:03:42Z")

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I am developing a python-VTK application and am noticing some unusual behavior in python unittest-based tests I am building alongside my application. I have noticed that tests that are defined in separate suites appear t…

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## [VTKHDF: 读入FieldData中的StringArray报错](https://discourse.vtk.org/t/vtkhdf-fielddata-stringarray/16154)

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**Author:** [@jie\_baoer](https://discourse.vtk.org/u/jie_baoer)\
**Replies:** 2\
**Last updated:** [November 24, 2025, 8:37am UTC](https://discourse.vtk.org/t/vtkhdf-fielddata-stringarray/16154 "2025-11-24T08:37:57Z")

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When I was testing vtkhdf, I found that when the read StringArray was n rows and multiple columns, an error would be prompted ERROR: In vtkHDFUtilities.cxx, line 558 (nullptr): Dataset: ndims: 2 greater than expected n…

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## [HU values incorrect after vtkImageReslice](https://discourse.vtk.org/t/hu-values-incorrect-after-vtkimagereslice/16152)

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**Author:** [@KSJ](https://discourse.vtk.org/u/KSJ)\
**Replies:** 2\
**Last updated:** [November 20, 2025, 5:10am UTC](https://discourse.vtk.org/t/hu-values-incorrect-after-vtkimagereslice/16152 "2025-11-20T05:10:29Z")

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I’m trying to reslice a DICOM volume using vtkImageReslice, but I’m having trouble preserving the original Hounsfield Unit (HU) values reslice-\>SetInputConnection(extractVOI-\>GetOutputPort()); reslice-\>SetResliceTransf…

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## [Compilers: Increase Minimum Microsoft Visual Studio Version to 2019](https://discourse.vtk.org/t/compilers-increase-minimum-microsoft-visual-studio-version-to-2019/16138)

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**Author:** [@spyridon97](https://discourse.vtk.org/u/spyridon97)\
**Replies:** 0\
**Last updated:** [November 12, 2025, 5:37pm UTC](https://discourse.vtk.org/t/compilers-increase-minimum-microsoft-visual-studio-version-to-2019/16138 "2025-11-12T17:37:02Z")

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Due to the addition of the scnlib library and an update in the expat library, the minimum supported version of Microsoft Visual Studio (MSVC) for building VTK will be increased to MSVC 2019. https://gitlab.kitware.com/v…

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## [Writing a vtk legacy file in binary format with Fortran. String datafield issue](https://discourse.vtk.org/t/writing-a-vtk-legacy-file-in-binary-format-with-fortran-string-datafield-issue/16136)

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**Author:** [@314tho](https://discourse.vtk.org/u/314tho)\
**Replies:** 2\
**Last updated:** [November 12, 2025, 9:10am UTC](https://discourse.vtk.org/t/writing-a-vtk-legacy-file-in-binary-format-with-fortran-string-datafield-issue/16136 "2025-11-12T09:10:47Z")

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Hi everybody ! To enable the visualization with Paraview of the results of my Fortran FE code, I developed in it the generation of a vtk file as output (legacy format, either ASCII or BINARY). The vtk legacy format is q…

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## [OSMesa implementation changing](https://discourse.vtk.org/t/osmesa-implementation-changing/4781)

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**Author:** [@anholt](https://discourse.vtk.org/u/anholt)\
**Replies:** 5\
**Last updated:** [November 6, 2025, 3:37pm UTC](https://discourse.vtk.org/t/osmesa-implementation-changing/4781 "2025-11-06T15:37:11Z")

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Hi! I’m a Mesa developer looking to clean up some of the cruft in our tree, and hopefully going to delete our OSMesa implementation based on the old software rasterizer. I’ve got an MR up for that (https://gitlab.freed…

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## [Rotating around specific point](https://discourse.vtk.org/t/rotating-around-specific-point/15433)

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**Author:** [@sapvi](https://discourse.vtk.org/u/sapvi)\
**Replies:** 9\
**Last updated:** [November 3, 2025, 4:58pm UTC](https://discourse.vtk.org/t/rotating-around-specific-point/15433 "2025-11-03T16:58:56Z")

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Hi all. I have self.picker = vtk.vtkPointPicker() to select the point in the point cloud. And I would like to be able by double-click on some point, make this point center of the rotation WITHOUT shifting the camera so …

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## [Bar Charts with Large Numbers](https://discourse.vtk.org/t/bar-charts-with-large-numbers/16051)

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**Author:** [@Jessica\_Marquis](https://discourse.vtk.org/u/Jessica_Marquis)\
**Replies:** 10\
**Last updated:** [October 31, 2025, 3:50pm UTC](https://discourse.vtk.org/t/bar-charts-with-large-numbers/16051 "2025-10-31T15:50:42Z")

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I am trying to create bar charts and I have found that once you reach large enough numbers for either the x axis (bin ranges) or the y axis (bin sizes), the chart no longer shows up as expected. To test this, you can edi…

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## [vtkResizingWindowToImageFilter and alpha/transparent backgrounds](https://discourse.vtk.org/t/vtkresizingwindowtoimagefilter-and-alpha-transparent-backgrounds/16110)

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**Author:** [@geoffw](https://discourse.vtk.org/u/geoffw)\
**Replies:** 2\
**Last updated:** [October 27, 2025, 12:16pm UTC](https://discourse.vtk.org/t/vtkresizingwindowtoimagefilter-and-alpha-transparent-backgrounds/16110 "2025-10-27T12:16:33Z")

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Just wanted to let the community know that vtkResizingWindowToImageFilter does not appear to properly handle the alpha channel. Setting SetInputBufferTypeToRGBA does not add a 4th element to the output. This was annoying…

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## [How to get full cell types array with new VTK 9.6 API](https://discourse.vtk.org/t/how-to-get-full-cell-types-array-with-new-vtk-9-6-api/16106)

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**Author:** [@user27182](https://discourse.vtk.org/u/user27182)\
**Replies:** 16\
**Last updated:** [October 24, 2025, 6:54am UTC](https://discourse.vtk.org/t/how-to-get-full-cell-types-array-with-new-vtk-9-6-api/16106 "2025-10-24T06:54:07Z")

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GetCellTypesArray is recently deprecated. Using the latest python dev wheels: \>\>\> import vtk \>\>\> grid = vtk.vtkUnstructuredGrid() \>\>\> array = grid.GetCellTypesArray() DeprecationWarning: Call to deprecated method GetCel…

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## [VTK Incorrect Shadows](https://discourse.vtk.org/t/vtk-incorrect-shadows/5057)

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**Author:** [@Andrew](https://discourse.vtk.org/u/Andrew)\
**Replies:** 5\
**Last updated:** [October 21, 2025, 2:46pm UTC](https://discourse.vtk.org/t/vtk-incorrect-shadows/5057 "2025-10-21T14:46:56Z")

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I’ve been playing around with shadows in VTK as of lately. I may be wrong, but I’m pretty sure they have issues. Here’s a slightly modified example from the VTK examples. Reduced to one light directly above the sphere. S…

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## [how to fix the view after I change the focus of the camera](https://discourse.vtk.org/t/how-to-fix-the-view-after-i-change-the-focus-of-the-camera/16091)

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**Author:** [@sophia](https://discourse.vtk.org/u/sophia)\
**Replies:** 3\
**Last updated:** [October 20, 2025, 7:52pm UTC](https://discourse.vtk.org/t/how-to-fix-the-view-after-i-change-the-focus-of-the-camera/16091 "2025-10-20T19:52:30Z")

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Dear all, i have a issue that the view need to ratate around by the point mouse clicked. i set the point to the camera‘s focus .so the view is exactly rotating the point ,but the change of focus also caused the center …

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## [Python Additional Wheels upload schedule](https://discourse.vtk.org/t/python-additional-wheels-upload-schedule/16100)

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**Author:** [@user27182](https://discourse.vtk.org/u/user27182)\
**Replies:** 1\
**Last updated:** [October 20, 2025, 2:14am UTC](https://discourse.vtk.org/t/python-additional-wheels-upload-schedule/16100 "2025-10-20T02:14:23Z")

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What is the upload schedule for the python dev wheels in the GitLab Package Registry? It seems that historically there is a new upload sometimes weekly, sometimes biweekly. But the latest VTK dev wheel upload is from Oc…

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## [Color space of RGB values in vtkProperty](https://discourse.vtk.org/t/color-space-of-rgb-values-in-vtkproperty/16088)

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**Author:** [@lassoan](https://discourse.vtk.org/u/lassoan)\
**Replies:** 3\
**Last updated:** [October 15, 2025, 3:34pm UTC](https://discourse.vtk.org/t/color-space-of-rgb-values-in-vtkproperty/16088 "2025-10-15T15:34:30Z")

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We see incorrect, washed-out colors in the 3D rendering if we change Interpolation to PBR in vtkProperty. For example, the image below shows that if we use the same RGB values with Gouraud interpolation (first column) an…

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## [how to reset geometry with on actors with trame](https://discourse.vtk.org/t/how-to-reset-geometry-with-on-actors-with-trame/16074)

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**Author:** [@jtristanod3d](https://discourse.vtk.org/u/jtristanod3d)\
**Replies:** 1\
**Last updated:** [October 10, 2025, 3:07pm UTC](https://discourse.vtk.org/t/how-to-reset-geometry-with-on-actors-with-trame/16074 "2025-10-10T15:07:21Z")

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I’m iterating through pvd time steps where the geometry changes drastically. I need o update the actors accordingly. If I remove the actor and add new actors, I get VTK pipeline errors vtkDataSetMapper (0x3d09490) has…

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