# Development

**URL:** https://discourse.vtk.org/c/development/7.md?page=51

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

**Page:** 52

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## [Multivolume : Shading is not working](https://discourse.vtk.org/t/multivolume-shading-is-not-working/771)

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**Author:** [@CNA](https://discourse.vtk.org/u/CNA)\
**Replies:** 6\
**Last updated:** [April 26, 2019, 6:38pm UTC](https://discourse.vtk.org/t/multivolume-shading-is-not-working/771 "2019-04-26T18:38:50Z")

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Hi everyone, I am trying to use a vtkMultivolume with a vtkGPUVolumeRayCastMapper in 8.2 in c++ and I found something weird. When there is only on port used in the mapper and also one port used in the vtkMultivolume I …

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## [Module vtkRenderingNone not built even with VTK\_RENDERING\_BACKEND=None](https://discourse.vtk.org/t/module-vtkrenderingnone-not-built-even-with-vtk-rendering-backend-none/585)

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**Author:** [@romangrothausmann](https://discourse.vtk.org/u/romangrothausmann)\
**Replies:** 12\
**Last updated:** [April 25, 2019, 5:42pm UTC](https://discourse.vtk.org/t/module-vtkrenderingnone-not-built-even-with-vtk-rendering-backend-none/585 "2019-04-25T17:42:19Z")

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Hi. When trying to compile a minimal VTK to use with ITKVtkGlue=ON (https://github.com/romangrothausmann/ITK-VTK\_CLIs/blob/0add37a5d4a91eb7bbafdf0b66096f83a755958f/Dockerfile#L50), ITK cmake stops with: Requested modul…

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## [Proposal: Should we replace vtkStdString with std::string](https://discourse.vtk.org/t/proposal-should-we-replace-vtkstdstring-with-std-string/796)

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**Author:** [@Haocheng\_Liu](https://discourse.vtk.org/u/Haocheng_Liu)\
**Replies:** 13\
**Last updated:** [April 25, 2019, 2:53am UTC](https://discourse.vtk.org/t/proposal-should-we-replace-vtkstdstring-with-std-string/796 "2019-04-25T02:53:09Z")

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vtkStdString is introduced because in pre C++11 world, the symbol names are too long given by the standard STL string. Since now C++11 has improved a lot on std::string, this class has finished its mission. Should we rep…

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## [Is zfp used in VTK?](https://discourse.vtk.org/t/is-zfp-used-in-vtk/786)

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**Author:** [@opoplawski](https://discourse.vtk.org/u/opoplawski)\
**Replies:** 2\
**Last updated:** [April 22, 2019, 9:23pm UTC](https://discourse.vtk.org/t/is-zfp-used-in-vtk/786 "2019-04-22T21:23:21Z")

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There is ThirdParty/zfp in the VTK source - but I can’t find any evidence that it is in use. Is there some planned future use or should it be removed? https://gitlab.kitware.com/vtk/vtk/issues/17540

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## [VTK install directory control reduced in new build system](https://discourse.vtk.org/t/vtk-install-directory-control-reduced-in-new-build-system/811)

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**Author:** [@cryos](https://discourse.vtk.org/u/cryos)\
**Replies:** 3\
**Last updated:** [April 22, 2019, 4:23pm UTC](https://discourse.vtk.org/t/vtk-install-directory-control-reduced-in-new-build-system/811 "2019-04-22T16:23:52Z")

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We have been using VTK\_INSTALL\_LIBRARY\_DIR, VTK\_INSTALL\_ARCHIVE\_DIR etc to control where VTK (and ParaView) install their files. We did this to simplify packaging by removing version information from install directories,…

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## [vtkloguru link errors building Mac app that doesn't use CMake](https://discourse.vtk.org/t/vtkloguru-link-errors-building-mac-app-that-doesnt-use-cmake/795)

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**Author:** [@seanm](https://discourse.vtk.org/u/seanm)\
**Replies:** 2\
**Last updated:** [April 19, 2019, 8:13pm UTC](https://discourse.vtk.org/t/vtkloguru-link-errors-building-mac-app-that-doesnt-use-cmake/795 "2019-04-19T20:13:05Z")

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Hi all, For the first time in a few months, I’m trying to build my Mac app against vtk master. I’m getting link errors like: “vtkloguru::vstrprintf(char const\*, \_\_va\_list\_tag\*)”, referenced from: vtkLogger::LogScopeR…

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## [Should we replace SafeDownCast with dynamic\_cast](https://discourse.vtk.org/t/should-we-replace-safedowncast-with-dynamic-cast/669)

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**Author:** [@lorensen](https://discourse.vtk.org/u/lorensen)\
**Replies:** 9\
**Last updated:** [April 19, 2019, 1:44am UTC](https://discourse.vtk.org/t/should-we-replace-safedowncast-with-dynamic-cast/669 "2019-04-19T01:44:59Z")

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Folks, SafeDownCast was added to vtk way back when dynamic\_cast was not available everywhere. Should we replace SafeDownCast in vtk with dynamic\_cast? It is more natural for modern C++ and is well-documented. It may …

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## [for(vtkDataObject \*ds : vtk::Range(multiblock\_ds)) { .. }](https://discourse.vtk.org/t/for-vtkdataobject-ds-vtk-range-multiblock-ds/262)

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**Author:** [@allison.vacanti](https://discourse.vtk.org/u/allison.vacanti)\
**Replies:** 7\
**Last updated:** [April 18, 2019, 3:51pm UTC](https://discourse.vtk.org/t/for-vtkdataobject-ds-vtk-range-multiblock-ds/262 "2019-04-18T15:51:18Z")

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Similar to the vtk::DataArrayTupleRange, vtk::DataArrayValueRange, and vtk::Range(vtkCollection\*) helpers added recently, it’s the vtkCompositeDataSet hierarchy’s turn to get C++11 for-range support: https://gitlab.kitw…

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## [How to evaluate if I'd benefit from using Intel TBB with VTK?](https://discourse.vtk.org/t/how-to-evaluate-if-id-benefit-from-using-intel-tbb-with-vtk/736)

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**Author:** [@seanm](https://discourse.vtk.org/u/seanm)\
**Replies:** 7\
**Last updated:** [April 11, 2019, 2:55pm UTC](https://discourse.vtk.org/t/how-to-evaluate-if-id-benefit-from-using-intel-tbb-with-vtk/736 "2019-04-11T14:55:46Z")

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Hi all, How can I evaluate if I’d benefit from using Intel TBB with VTK? That is, is there a list of VTK classes that use it? Or is there some TBB bottleneck function that I could put a breakpoint on to see if my app’…

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## [Volume rendering with shading on : light orientation issue when user matrix has been modified](https://discourse.vtk.org/t/volume-rendering-with-shading-on-light-orientation-issue-when-user-matrix-has-been-modified/715)

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**Author:** [@renaud-lebrun](https://discourse.vtk.org/u/renaud-lebrun)\
**Replies:** 13\
**Last updated:** [April 11, 2019, 9:38am UTC](https://discourse.vtk.org/t/volume-rendering-with-shading-on-light-orientation-issue-when-user-matrix-has-been-modified/715 "2019-04-11T09:38:17Z")

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Dear All, I have a question regarding volume mapper shading related with light orientation. I develop a VTK based application ( https://github.com/morphomuseum/MorphoDig ), in which I use 3D rendering of a 3D volume w…

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## [How to write STL from x y z co-ordinates ?](https://discourse.vtk.org/t/how-to-write-stl-from-x-y-z-co-ordinates/711)

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**Author:** [@selvakarna](https://discourse.vtk.org/u/selvakarna)\
**Replies:** 3\
**Last updated:** [April 9, 2019, 2:27pm UTC](https://discourse.vtk.org/t/how-to-write-stl-from-x-y-z-co-ordinates/711 "2019-04-09T14:27:15Z")

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How to write STL from x y z co-ordinates? x y z are extracted from 3D volume images, so my goal is x y z convert to STL?

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## [vtkpython 3.7 error with windows debug build](https://discourse.vtk.org/t/vtkpython-3-7-error-with-windows-debug-build/692)

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**Author:** [@Aron\_Helser](https://discourse.vtk.org/u/Aron_Helser)\
**Replies:** 8\
**Last updated:** [April 8, 2019, 3:11pm UTC](https://discourse.vtk.org/t/vtkpython-3-7-error-with-windows-debug-build/692 "2019-04-08T15:11:27Z")

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I’m seeing an error when trying to use vtkpython with python 3.7 and a debug build: Python 3.7.3 (v3.7.3:ef4ec6ed12, Mar 25 2019, 22:22:05) \[MSC v.1916 64 bit (AMD64)\] on win32 Type “help”, “copyright”, “credits” or “l…

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## [vtkAbstractPicker::SetPropCollection](https://discourse.vtk.org/t/vtkabstractpicker-setpropcollection/683)

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**Author:** [@andreasbuykx](https://discourse.vtk.org/u/andreasbuykx)\
**Replies:** 0\
**Last updated:** [April 4, 2019, 8:00am UTC](https://discourse.vtk.org/t/vtkabstractpicker-setpropcollection/683 "2019-04-04T08:00:06Z")

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There is no method to assign a new prop collection to a picker, but all methods are in place to modify the prop collection, and the prop collection itself is accessible for modification. This however requires iterating o…

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## [Merge topic 'revert-shader-properties'](https://discourse.vtk.org/t/merge-topic-revert-shader-properties/659)

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**Author:** [@amaclean](https://discourse.vtk.org/u/amaclean)\
**Replies:** 3\
**Last updated:** [April 3, 2019, 1:25pm UTC](https://discourse.vtk.org/t/merge-topic-revert-shader-properties/659 "2019-04-03T13:25:45Z")

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Please consider using deprecation in future. I just had to revert a whole lot of changes to the VTKExamples. Thanks Andrew

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## [Applying clustering algorithms to a volume surface](https://discourse.vtk.org/t/applying-clustering-algorithms-to-a-volume-surface/672)

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**Author:** [@LVittorelli](https://discourse.vtk.org/u/LVittorelli)\
**Replies:** 0\
**Last updated:** [April 3, 2019, 9:34am UTC](https://discourse.vtk.org/t/applying-clustering-algorithms-to-a-volume-surface/672 "2019-04-03T09:34:01Z")

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Hello, I’m trying to compare some OpenFOAM CFD simulations that reproduce the flow through an almost spherical object(the object is a reconstruction, with an irregular shape), searching for the one with the smallest clu…

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## [draw lines on DICOM image with vtkImageViewer2](https://discourse.vtk.org/t/draw-lines-on-dicom-image-with-vtkimageviewer2/652)

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**Author:** [@719mikelee5](https://discourse.vtk.org/u/719mikelee5)\
**Replies:** 0\
**Last updated:** [April 1, 2019, 3:53am UTC](https://discourse.vtk.org/t/draw-lines-on-dicom-image-with-vtkimageviewer2/652 "2019-04-01T03:53:35Z")

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Hello, friends I’m trying to draw lines on DICOM CT image. vtkImageViewer2 is my prefer to display the DICOM image. And I need to draw lines on the displayed image too, but it seems could not work. I found that vtkIma…

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## [Struggling with geographic coordinates](https://discourse.vtk.org/t/struggling-with-geographic-coordinates/596)

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**Author:** [@cobo](https://discourse.vtk.org/u/cobo)\
**Replies:** 17\
**Last updated:** [March 31, 2019, 1:09pm UTC](https://discourse.vtk.org/t/struggling-with-geographic-coordinates/596 "2019-03-31T13:09:59Z")

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In my models I am working with geographic coordinates, which are meters in a range between -10’000 and +10’000, and some applications require a precision down to cm or mm - which is not covered any more with “float” data…

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## [vtkJavaMemoryManager issue](https://discourse.vtk.org/t/vtkjavamemorymanager-issue/628)

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**Author:** [@mat127](https://discourse.vtk.org/u/mat127)\
**Replies:** 7\
**Last updated:** [March 30, 2019, 12:30am UTC](https://discourse.vtk.org/t/vtkjavamemorymanager-issue/628 "2019-03-30T00:30:32Z")

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Hello, maybe I am missing something but it seems to me that there is an issue in the vtkJavaMemoryManagerImpl class. Let me describe the scenario: I am overriding in my Java code the vtkPolygonalHandleRepresentation3D …

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## [vtkSmartPointer and vtkNew in VTK's API. Best practices?](https://discourse.vtk.org/t/vtksmartpointer-and-vtknew-in-vtks-api-best-practices/518)

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**Author:** [@allison.vacanti](https://discourse.vtk.org/u/allison.vacanti)\
**Replies:** 19\
**Last updated:** [March 27, 2019, 2:11pm UTC](https://discourse.vtk.org/t/vtksmartpointer-and-vtknew-in-vtks-api-best-practices/518 "2019-03-27T14:11:26Z")

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As best practices emerge in a post-C++11 world, one of the newer guidelines becoming commonplace is “don’t use raw pointers.” Preferring smart pointers prevents a host of mistakes and provides an additional level of safe…

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## [vtkScalarBarActor New macro problem](https://discourse.vtk.org/t/vtkscalarbaractor-new-macro-problem/610)

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**Author:** [@ramon.j.moral](https://discourse.vtk.org/u/ramon.j.moral)\
**Replies:** 2\
**Last updated:** [March 26, 2019, 10:07pm UTC](https://discourse.vtk.org/t/vtkscalarbaractor-new-macro-problem/610 "2019-03-26T22:07:02Z")

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Hello, I am using QtCreator to make a vtk App. I wanted to make a section of the app that shows the vtkScalarBarActor so the USER can get a feeling for the colors their going to use for their state plot. I have two li…

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## [vtkResliceImageViewer only shows one slice from a vtkImageData obtained from reslice filter](https://discourse.vtk.org/t/vtkresliceimageviewer-only-shows-one-slice-from-a-vtkimagedata-obtained-from-reslice-filter/607)

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**Author:** [@zandarina](https://discourse.vtk.org/u/zandarina)\
**Replies:** 0\
**Last updated:** [March 26, 2019, 3:57pm UTC](https://discourse.vtk.org/t/vtkresliceimageviewer-only-shows-one-slice-from-a-vtkimagedata-obtained-from-reslice-filter/607 "2019-03-26T15:57:38Z")

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Dear all, I have a question. I want to show using vtkResliceImageViewer the slices i have got from the reslicer filter. So i append in z the output and i call a fuction to show me the vtkImageData witth all the…

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## [Error handling](https://discourse.vtk.org/t/error-handling/603)

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**Author:** [@michal.wozniak](https://discourse.vtk.org/u/michal.wozniak)\
**Replies:** 0\
**Last updated:** [March 25, 2019, 4:36pm UTC](https://discourse.vtk.org/t/error-handling/603 "2019-03-25T16:36:11Z")

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Hi, What is the best way to handle VTK errors while chaining multiple VTK filters? Use vtkErrorCode to add specific error code and then do const bool result = filter-\>GetErrorCode() == vtkErrorCode ::NoError; //co…

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## [Query to import nifty image in lut color](https://discourse.vtk.org/t/query-to-import-nifty-image-in-lut-color/588)

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**Author:** [@svabhishek29](https://discourse.vtk.org/u/svabhishek29)\
**Replies:** 0\
**Last updated:** [March 21, 2019, 5:08pm UTC](https://discourse.vtk.org/t/query-to-import-nifty-image-in-lut-color/588 "2019-03-21T17:08:01Z")

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Hi, I am working on doing segmentation on medical images using neural networks and was trying to see if setting windowing to right levels helps in training the net to get better results. I was able to implement the look…

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## [vtkMultiThreshold strange API](https://discourse.vtk.org/t/vtkmultithreshold-strange-api/510)

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**Author:** [@lorensen](https://discourse.vtk.org/u/lorensen)\
**Replies:** 4\
**Last updated:** [March 21, 2019, 1:55pm UTC](https://discourse.vtk.org/t/vtkmultithreshold-strange-api/510 "2019-03-21T13:55:01Z")

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Folks and @dcthomp First, vtkMultiThreshold is a very interesting and useful class. I notice the only place it is used in vtk is in its unit test I decided to write an example: CellsInsideObject The filter documentati…

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## [How to create a vtkUnstructuredGrid in parallel](https://discourse.vtk.org/t/how-to-create-a-vtkunstructuredgrid-in-parallel/532)

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**Author:** [@SergeLalonde](https://discourse.vtk.org/u/SergeLalonde)\
**Replies:** 0\
**Last updated:** [March 19, 2019, 2:31pm UTC](https://discourse.vtk.org/t/how-to-create-a-vtkunstructuredgrid-in-parallel/532 "2019-03-19T14:31:08Z")

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Is it possible to initialize a vtkUnstructured grid in parallel? Ex: using OpenMP. The InsertNextCell() method is definitely not thread safe, even if Allocate() is called beforehand. If there was a SetCell(vtkIdType id…

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## [Building vtkDICOM as a Remote VTK Module with Java Wrapping fails](https://discourse.vtk.org/t/building-vtkdicom-as-a-remote-vtk-module-with-java-wrapping-fails/491)

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**Author:** [@lars\_matthaeus](https://discourse.vtk.org/u/lars_matthaeus)\
**Replies:** 3\
**Last updated:** [March 15, 2019, 3:51pm UTC](https://discourse.vtk.org/t/building-vtkdicom-as-a-remote-vtk-module-with-java-wrapping-fails/491 "2019-03-15T15:51:25Z")

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I’m trying to build VTK on Windows with VS 2017 (x64, Release). I have enabled the vtkDicom module in CMAKE as well as the VTK\_WRAP\_JAVA option (Java 1.8). When building the solution in VS, I get a linker error for the v…

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## [Improve const correctness of vtkAbstractDataArray, vtkPoints and derived classes](https://discourse.vtk.org/t/improve-const-correctness-of-vtkabstractdataarray-vtkpoints-and-derived-classes/404)

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**Author:** [@phcerdan](https://discourse.vtk.org/u/phcerdan)\
**Replies:** 9\
**Last updated:** [March 13, 2019, 3:45pm UTC](https://discourse.vtk.org/t/improve-const-correctness-of-vtkabstractdataarray-vtkpoints-and-derived-classes/404 "2019-03-13T15:45:49Z")

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vtkPoints::GetNumberOfPoints(), vtkAbstractDataArray::GetNumberOfTuples are not constant. This impedes to be const correct, void ReadPoints(const vtkPoints \*read\_only\_points) { auto npoints = read\_only\_points-\>…

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## [Point data from \`vtkProbeFilter\` lost after \`vtkSelectEnclosedPoints\`](https://discourse.vtk.org/t/point-data-from-vtkprobefilter-lost-after-vtkselectenclosedpoints/130)

<div class="topic-metadata">

**Author:** [@romangrothausmann](https://discourse.vtk.org/u/romangrothausmann)\
**Replies:** 1\
**Last updated:** [March 15, 2019, 9:20am UTC](https://discourse.vtk.org/t/point-data-from-vtkprobefilter-lost-after-vtkselectenclosedpoints/130 "2019-03-15T09:20:38Z")

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Hi. It seems that point data from vtkProbeFilter (e.g. MetaImage from probing an MHA with a VTP) is lost when processed afterwards with vtkSelectEnclosedPoints (only contains SelectedPoints and vktValidPointMask). Since…

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## [MultiBlockDataSet field data inaccessible from outer layer](https://discourse.vtk.org/t/multiblockdataset-field-data-inaccessible-from-outer-layer/482)

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**Author:** [@phil\_ossk](https://discourse.vtk.org/u/phil_ossk)\
**Replies:** 2\
**Last updated:** [March 14, 2019, 1:51pm UTC](https://discourse.vtk.org/t/multiblockdataset-field-data-inaccessible-from-outer-layer/482 "2019-03-14T13:51:44Z")

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Hello there, Before submitting a bug report, I am looking for your input on an issue I am facing. I have a MultiBlockDataSet (let’s call it mbds0) with several blocks . Some field data (testArray0 and testArray1) has b…

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## [Changing stereo-related flags](https://discourse.vtk.org/t/changing-stereo-related-flags/477)

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**Author:** [@utkarshayachit](https://discourse.vtk.org/u/utkarshayachit)\
**Replies:** 3\
**Last updated:** [March 14, 2019, 10:59am UTC](https://discourse.vtk.org/t/changing-stereo-related-flags/477 "2019-03-14T10:59:15Z")

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Currently there are 3 user-settable flags that affect whether and how vtkRenderWindow does stereo rendering: StereoCapableWindow, StereoRender and StereoType. All are user settable and the biggest annoyance is that there…

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