# Development

**URL:** https://discourse.vtk.org/c/development/7.md

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

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## [The ultimate "How to make CI work with my fork" guide](https://discourse.vtk.org/t/the-ultimate-how-to-make-ci-work-with-my-fork-guide/7581)

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**Author:** [@mwestphal](https://discourse.vtk.org/u/mwestphal)\
**Replies:** 13\
**Last updated:** [August 25, 2024, 9:59am UTC](https://discourse.vtk.org/t/the-ultimate-how-to-make-ci-work-with-my-fork-guide/7581 "2024-08-25T09:59:51Z")

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Go to your fork : https://gitlab.kitware.com/username/vtk/ Click on settings and expand Visibility Click on Settings, CI/CD and expand General Rebase your branch in MRs against the last origin master git fe…

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## [About the Development category](https://discourse.vtk.org/t/about-the-development-category/40)

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**Author:** [@cory.quammen](https://discourse.vtk.org/u/cory.quammen)\
**Replies:** 0

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The Development category is for the discussion of VTK development, including potential bugs, new features, software testing, and related topics.

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## [vtkXOpenGLRenderWindow::DestroyWindow() can deadlock when Finalize() runs from QVTKRenderWindowInteractor.closeEvent()](https://discourse.vtk.org/t/vtkxopenglrenderwindow-destroywindow-can-deadlock-when-finalize-runs-from-qvtkrenderwindowinteractor-closeevent/16515)

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**Author:** [@DungTruog](https://discourse.vtk.org/u/DungTruog)\
**Replies:** 1\
**Last updated:** [September 17, 2026, 6:52pm UTC](https://discourse.vtk.org/t/vtkxopenglrenderwindow-destroywindow-can-deadlock-when-finalize-runs-from-qvtkrenderwindowinteractor-closeevent/16515 "2026-09-17T18:52:37Z")

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We meet an intermittent SIGSEGV on closing a Qt window that embeds \`QVTKRenderWindowInteractor\`. Confirmed via a core-dump backtrace and by reading \`vtkXOpenGLRenderWindow\`: the vendored interactor only finalizes its ren…

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## [Migration of macOS CI work](https://discourse.vtk.org/t/migration-of-macos-ci-work/16529)

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**Author:** [@ben.boeckel](https://discourse.vtk.org/u/ben.boeckel)\
**Replies:** 2\
**Last updated:** [September 16, 2026, 4:08pm UTC](https://discourse.vtk.org/t/migration-of-macos-ci-work/16529 "2026-09-16T16:08:19Z")

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Hi, As I’m sure many have noticed, macOS CI testing for VTK has been rough lately. We’ve been in the middle of a transition from running directly on the hardware to instead using VMs to run the jobs. Now that VTK has me…

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## [Line elements cause missing edges in triangle cells](https://discourse.vtk.org/t/line-elements-cause-missing-edges-in-triangle-cells/16521)

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**Author:** [@raungst](https://discourse.vtk.org/u/raungst)\
**Replies:** 5\
**Last updated:** [September 4, 2026, 7:54pm UTC](https://discourse.vtk.org/t/line-elements-cause-missing-edges-in-triangle-cells/16521 "2026-09-04T19:54:53Z")

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This started in VTK 9.6, but is present in 9.7 as well. I’m not sure how pervasive it is, but if I have an unstructured grid with only triangles and lines, the triangles don’t have edges shown. If I don’t have the lines,…

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## [About proper distributed AbortCheck](https://discourse.vtk.org/t/about-proper-distributed-abortcheck/16315)

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**Author:** [@mwestphal](https://discourse.vtk.org/u/mwestphal)\
**Replies:** 6\
**Last updated:** [August 26, 2026, 8:38am UTC](https://discourse.vtk.org/t/about-proper-distributed-abortcheck/16315 "2026-08-26T08:38:25Z")

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Context A few years ago, @Stephen\_Crowell @Christos\_Tsolakis and @berk.geveci led an effort to improve abort mechanism in VTK, this effort was not fully integrated but great point and design were made here: https://git…

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## [Improving Abort Functionality in VTK](https://discourse.vtk.org/t/improving-abort-functionality-in-vtk/7813)

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**Author:** [@Stephen\_Crowell](https://discourse.vtk.org/u/Stephen_Crowell)\
**Replies:** 6\
**Last updated:** [August 26, 2026, 8:36am UTC](https://discourse.vtk.org/t/improving-abort-functionality-in-vtk/7813 "2026-08-26T08:36:59Z")

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Currently, the abort mechanism is designed to function only within a single thread when the abort flag is set by an observer of the progress event. This severely limits the usefulness of the functionality as evidenced by…

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## [Mismatch of points/tuples between vtkmCleanGrid and its VTK-numpy-wrapper](https://discourse.vtk.org/t/mismatch-of-points-tuples-between-vtkmcleangrid-and-its-vtk-numpy-wrapper/16517)

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**Author:** [@Bodacious](https://discourse.vtk.org/u/Bodacious)\
**Replies:** 1\
**Last updated:** [August 25, 2026, 4:13pm UTC](https://discourse.vtk.org/t/mismatch-of-points-tuples-between-vtkmcleangrid-and-its-vtk-numpy-wrapper/16517 "2026-08-25T16:13:14Z")

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Hello, This post is a repost of https://discourse.paraview.org/t/mismatch-of-points-tuples-between-vtkmcleangrid-and-its-vtk-numpy-wrapper/17698?u=bodacious after @mwestphal proposition. I have a vtkUnstructuredGrid dat…

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## [VTK::ViewsRendering: new View and Representation classes](https://discourse.vtk.org/t/vtk-new-view-and-representation-classes/16510)

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**Author:** [@berk.geveci](https://discourse.vtk.org/u/berk.geveci)\
**Replies:** 6\
**Last updated:** [August 14, 2026, 1:57pm UTC](https://discourse.vtk.org/t/vtk-new-view-and-representation-classes/16510 "2026-08-14T13:57:17Z")

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The VTK::ViewsRendering module merged to master last week (!13418). It is the beginning of a view and representation layer for scientific visualization in VTK, and since there is a good deal more to come, we wanted to ex…

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## [Colors in VTK have no declared color space, with consequences throughout the codebase](https://discourse.vtk.org/t/colors-in-vtk-have-no-declared-color-space-with-consequences-throughout-the-codebase/16503)

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**Author:** [@mhalle](https://discourse.vtk.org/u/mhalle)\
**Replies:** 2\
**Last updated:** [August 4, 2026, 3:26pm UTC](https://discourse.vtk.org/t/colors-in-vtk-have-no-declared-color-space-with-consequences-throughout-the-codebase/16503 "2026-08-04T15:26:53Z")

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I’ve been investigating a core VTK issue with colors for a little while now. This issue is pervasive in VTK and VTK.js, and most likely other derived software. Luckily, I think there’s a gradual fix for it. The core is…

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## [Enable hardware selection even with installed render pass](https://discourse.vtk.org/t/enable-hardware-selection-even-with-installed-render-pass/16494)

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**Author:** [@peter.thompson](https://discourse.vtk.org/u/peter.thompson)\
**Replies:** 0\
**Last updated:** [July 27, 2026, 9:40pm UTC](https://discourse.vtk.org/t/enable-hardware-selection-even-with-installed-render-pass/16494 "2026-07-27T21:40:54Z")

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I recently ran into something similar to this issue: vtkShadowMapPass causes actor picking doesn't work,and the actors with vtkUnstructuredGrid source don't show anymore. To summarize the issue: installing a render pass …

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## [Runtime control for object factory overrides](https://discourse.vtk.org/t/runtime-control-for-object-factory-overrides/16253)

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**Author:** [@jaswantp](https://discourse.vtk.org/u/jaswantp)\
**Replies:** 2\
**Last updated:** [July 27, 2026, 7:08pm UTC](https://discourse.vtk.org/t/runtime-control-for-object-factory-overrides/16253 "2026-07-27T19:08:33Z")

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I’d like to highlight a new feature that allows applications to control vtkObjectFactory overrides at runtime. Previously, applications linking to multiple VTK modules such as RenderingOpenGL and RenderingWebGPU(experim…

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## [How to transition away from vtkSurfaceNets3D SetOutputStyleToSelected API](https://discourse.vtk.org/t/how-to-transition-away-from-vtksurfacenets3d-setoutputstyletoselected-api/16474)

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**Author:** [@user27182](https://discourse.vtk.org/u/user27182)\
**Replies:** 16\
**Last updated:** [July 24, 2026, 7:45pm UTC](https://discourse.vtk.org/t/how-to-transition-away-from-vtksurfacenets3d-setoutputstyletoselected-api/16474 "2026-07-24T19:45:34Z")

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The following code creates image data with two regions, where one region (ID 2) is surrounded by background values (ID 0) on all sides except for one, where there is a single shared boundary with another region (ID 5). U…

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## [Restoring the C++Builder visual component from VTK 7 and 8](https://discourse.vtk.org/t/restoring-the-c-builder-visual-component-from-vtk-7-and-8/15053)

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**Author:** [@davidmillington](https://discourse.vtk.org/u/davidmillington)\
**Replies:** 21\
**Last updated:** [July 20, 2026, 7:05pm UTC](https://discourse.vtk.org/t/restoring-the-c-builder-visual-component-from-vtk-7-and-8/15053 "2026-07-20T19:05:58Z")

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Hello. VTK versions 7 and 8 shipped with a visual component/widget for C++Builder (eg: VTK-7.1.1\\Examples\\GUI\\Win32\\vtkBorland\\Package). This is not present in VTK 9. Is it possible to restore this please? I filed an i…

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## [Enabling options on CI](https://discourse.vtk.org/t/enabling-options-on-ci/16484)

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**Author:** [@cory.quammen](https://discourse.vtk.org/u/cory.quammen)\
**Replies:** 1\
**Last updated:** [July 15, 2026, 3:16pm UTC](https://discourse.vtk.org/t/enabling-options-on-ci/16484 "2026-07-15T15:16:32Z")

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I am trying to enable the VTK::IOUSD module in a CI build, namely fedora42\_x86\_64\_mpi\_python\_qt\_tbb.cmake, copied here for reference with my changes: set(VTK\_USE\_EXTERNAL ON CACHE STRING "") # These libraries are not s…

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## [Issue with QVTKRenderWindowInteractor and PySide6 6.10.1 on MacOS](https://discourse.vtk.org/t/issue-with-qvtkrenderwindowinteractor-and-pyside6-6-10-1-on-macos/16225)

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**Author:** [@nchampag](https://discourse.vtk.org/u/nchampag)\
**Replies:** 16\
**Last updated:** [July 14, 2026, 3:06pm UTC](https://discourse.vtk.org/t/issue-with-qvtkrenderwindowinteractor-and-pyside6-6-10-1-on-macos/16225 "2026-07-14T15:06:45Z")

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The issue is code with QVTKRenderWindowInteractor on macOS that worked with VTK 9.4.2 and PySide6 6.9.3 fails to display anything after updating to PySide 6.10.1. No error message is displayed–it just hangs. Pressing c…

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## [VTK Examples, changes to the Curvature examples](https://discourse.vtk.org/t/vtk-examples-changes-to-the-curvature-examples/16473)

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**Author:** [@amaclean](https://discourse.vtk.org/u/amaclean)\
**Replies:** 0\
**Last updated:** [June 23, 2026, 11:47pm UTC](https://discourse.vtk.org/t/vtk-examples-changes-to-the-curvature-examples/16473 "2026-06-23T23:47:06Z")

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These examples have been grouped together to make it easier to find them and to showcase the different techniques. The PythonicAPI versions have been rewritten/improved with the changes being reflected in the C++ versio…

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## [Duplicate GetGroup/GetBinding in vtkWebGPUComputeBuffer.h](https://discourse.vtk.org/t/duplicate-getgroup-getbinding-in-vtkwebgpucomputebuffer-h/16467)

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**Author:** [@Bengt](https://discourse.vtk.org/u/Bengt)\
**Replies:** 9\
**Last updated:** [June 23, 2026, 11:13am UTC](https://discourse.vtk.org/t/duplicate-getgroup-getbinding-in-vtkwebgpucomputebuffer-h/16467 "2026-06-23T11:13:38Z")

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Building VTK 9.6.2 with WebGPU enabled on Windows / MSVC fails to compile Rendering/WebGPU/vtkWebGPUComputeBuffer.h. Group and Binding are declared as vtkIdType members but each accessor is defined twice, once hand-writ…

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## [Upgrading VTK widgets framework](https://discourse.vtk.org/t/upgrading-vtk-widgets-framework/16455)

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**Author:** [@jadh4v](https://discourse.vtk.org/u/jadh4v)\
**Replies:** 4\
**Last updated:** [June 19, 2026, 3:35pm UTC](https://discourse.vtk.org/t/upgrading-vtk-widgets-framework/16455 "2026-06-19T15:35:54Z")

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As part of our future roadmap for VTK, we are planning to upgrade the VTK widgets framework to better support applications in managing and synchronizing widgets and their properties. This mainly includes synchronization …

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## [vtkTable support in VTKHDF](https://discourse.vtk.org/t/vtktable-support-in-vtkhdf/16460)

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**Author:** [@Louis\_Gombert](https://discourse.vtk.org/u/Louis_Gombert)\
**Replies:** 1\
**Last updated:** [June 16, 2026, 2:05pm UTC](https://discourse.vtk.org/t/vtktable-support-in-vtkhdf/16460 "2026-06-16T14:05:53Z")

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vtkTable is one of the last important VTK data types that has not been added to the VTKHDF specification yet. I’m presenting here a specification to fill this gap and get feedback from the community before implementing i…

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## [Discrepancy between vtkPLYReader and vtkSTLReader when streaming.](https://discourse.vtk.org/t/discrepancy-between-vtkplyreader-and-vtkstlreader-when-streaming/16443)

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**Author:** [@Seun](https://discourse.vtk.org/u/Seun)\
**Replies:** 2\
**Last updated:** [June 9, 2026, 12:56pm UTC](https://discourse.vtk.org/t/discrepancy-between-vtkplyreader-and-vtkstlreader-when-streaming/16443 "2026-06-09T12:56:10Z")

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Hi everyone, I was wondering why there seems to be a difference in usage of vtkMemoryResourceStream with both PLY & STL readers. the former requires explicit declaration of turning on the stream despite setting the buf…

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## [About missing VTK doxygen documentation](https://discourse.vtk.org/t/about-missing-vtk-doxygen-documentation/9926)

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**Author:** [@mwestphal](https://discourse.vtk.org/u/mwestphal)\
**Replies:** 4\
**Last updated:** [June 8, 2026, 8:43am UTC](https://discourse.vtk.org/t/about-missing-vtk-doxygen-documentation/9926 "2026-06-08T08:43:46Z")

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VTK doxygen documentation is functionnal, but only concerns “nigthly” which is roughly master: https://vtk.org/doc/nightly/html/ There is no way to access doxygen documentation of the last release, or older release. T…

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## [vtkPointGaussianMapper with Shader replacement](https://discourse.vtk.org/t/vtkpointgaussianmapper-with-shader-replacement/16438)

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**Author:** [@Sandipan](https://discourse.vtk.org/u/Sandipan)\
**Replies:** 1\
**Last updated:** [May 28, 2026, 8:31am UTC](https://discourse.vtk.org/t/vtkpointgaussianmapper-with-shader-replacement/16438 "2026-05-28T08:31:39Z")

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am using ActiViz / VTK 9.5 in a .NET desktop application for large point-cloud visualization. I am trying to implement fast class visibility toggling for LAS-style classification data. Current data model: vtkPolyData …

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## [UnstructuredGrid Filter extracts too many cells](https://discourse.vtk.org/t/unstructuredgrid-filter-extracts-too-many-cells/16433)

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**Author:** [@magicmangoman](https://discourse.vtk.org/u/magicmangoman)\
**Replies:** 2\
**Last updated:** [May 27, 2026, 6:28am UTC](https://discourse.vtk.org/t/unstructuredgrid-filter-extracts-too-many-cells/16433 "2026-05-27T06:28:12Z")

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Extracted surface of Bipyramid has too many cells In the documentation of vtkUnstructuredGridGeometryFilter it is stated that this filter provides the following functionality: Geometry is obtained as follows: all 0D, 1…

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## [Differentiable rendering module with PyTorch integration for VTK](https://discourse.vtk.org/t/differentiable-rendering-module-with-pytorch-integration-for-vtk/16401)

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**Author:** [@Juan\_C\_Prieto](https://discourse.vtk.org/u/Juan_C_Prieto)\
**Replies:** 3\
**Last updated:** [May 26, 2026, 3:31pm UTC](https://discourse.vtk.org/t/differentiable-rendering-module-with-pytorch-integration-for-vtk/16401 "2026-05-26T15:31:26Z")

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Summary I would like to propose the addition of a differentiable rendering module to VTK — tentatively VTK::RenderingDifferentiable — that exposes gradients through VTK’s rendering pipeline and bridges them to PyTorch’s …

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## [test timeouts vs slow debug tools like thread sanitizer](https://discourse.vtk.org/t/test-timeouts-vs-slow-debug-tools-like-thread-sanitizer/16425)

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**Author:** [@seanm](https://discourse.vtk.org/u/seanm)\
**Replies:** 8\
**Last updated:** [May 20, 2026, 7:02pm UTC](https://discourse.vtk.org/t/test-timeouts-vs-slow-debug-tools-like-thread-sanitizer/16425 "2026-05-20T19:02:51Z")

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Hi all, I’ve recently been trying to get more VTK tests to pass under thread sanitizer. TSan can cause 10x runtime slowdown. This makes some tests timeout. Most interesting are ones like IOEnSightPython-TestEnSightGoldC…

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## [Crash in vtkImageExport](https://discourse.vtk.org/t/crash-in-vtkimageexport/16415)

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**Author:** [@nbeck](https://discourse.vtk.org/u/nbeck)\
**Replies:** 2\
**Last updated:** [May 12, 2026, 6:20pm UTC](https://discourse.vtk.org/t/crash-in-vtkimageexport/16415 "2026-05-12T18:20:52Z")

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Hello, we’ve encountered spurious crashes with our application when processing large data sets. Some debugging revealed that we had invalid memory access in vtkImageExport::export(). Further investigation showed that th…

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## [XMLUnstructuredGridReader ignores already existing array names in time-series](https://discourse.vtk.org/t/xmlunstructuredgridreader-ignores-already-existing-array-names-in-time-series/16414)

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**Author:** [@jobojeha](https://discourse.vtk.org/u/jobojeha)\
**Replies:** 0\
**Last updated:** [May 12, 2026, 9:15am UTC](https://discourse.vtk.org/t/xmlunstructuredgridreader-ignores-already-existing-array-names-in-time-series/16414 "2026-05-12T09:15:28Z")

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I’ve been working with VTK UnstructuredGrid files that contain time series. In your external test files I found cube-with-time.vtu which is essentially doing the same thing. Similar to how its described here Field Data a…

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## [RayCastMapper for SDF](https://discourse.vtk.org/t/raycastmapper-for-sdf/16409)

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**Author:** [@Jens\_Munk\_Hansen](https://discourse.vtk.org/u/Jens_Munk_Hansen)\
**Replies:** 2\
**Last updated:** [May 10, 2026, 8:15pm UTC](https://discourse.vtk.org/t/raycastmapper-for-sdf/16409 "2026-05-10T20:15:35Z")

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Hi Developers We’ve prototyped a single-surface sphere-tracing mapper by forking vtkOpenGLGPUVolumeRayCastMapper. The fork keeps all of the parent’s pipeline plumbing — NDC→texture ray setup, depth-buffer composition, …

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## [Do we need a testing framework example?](https://discourse.vtk.org/t/do-we-need-a-testing-framework-example/16399)

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**Author:** [@amaclean](https://discourse.vtk.org/u/amaclean)\
**Replies:** 4\
**Last updated:** [May 5, 2026, 5:39am UTC](https://discourse.vtk.org/t/do-we-need-a-testing-framework-example/16399 "2026-05-05T05:39:07Z")

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The background to this is that I have created a MR: Moving to ssim and fixing tests which seems to be working in that, for Linux, only two fail out of 1023 C++ tests and, for Windows, 18 tests fail out of 1021. So I wil…

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