# Latest

**URL:** https://discourse.vtk.org/latest.md?page=143

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

**Page:** 144

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## [Single polydata, different mappers for different scalars?](https://discourse.vtk.org/t/single-polydata-different-mappers-for-different-scalars/7775)

<div class="topic-metadata">

**Author:** [@nicoco](https://discourse.vtk.org/u/nicoco)\
**Replies:** 2\
**Last updated:** [February 14, 2022, 3:27pm UTC](https://discourse.vtk.org/t/single-polydata-different-mappers-for-different-scalars/7775 "2022-02-14T15:27:25Z")

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Hey all, I am trying to use a single polydata with differents point data scalars mapped to it in vtk.js but I did not manage how to do it. I tried: polyData.getPointData().setActiveScalars(polyData.getPointData().getAr…

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## [After clip using vtkClipPolyData, stll remain faces](https://discourse.vtk.org/t/after-clip-using-vtkclippolydata-stll-remain-faces/7830)

<div class="topic-metadata">

**Author:** [@feierpusier](https://discourse.vtk.org/u/feierpusier)\
**Replies:** 2\
**Last updated:** [February 14, 2022, 12:02pm UTC](https://discourse.vtk.org/t/after-clip-using-vtkclippolydata-stll-remain-faces/7830 "2022-02-14T12:02:10Z")

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I used vtkClipPolyData function to clip a vtkPolyData with a vtkSphere(radius 0.38, center(-2.27855,-2.97874,-2.43147)),but four faces (red faces in below figure) still remain. The figure below demonstrated the vtkPolyDa…

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## [How to interpolate array data using gauss points (quadrature)](https://discourse.vtk.org/t/how-to-interpolate-array-data-using-gauss-points-quadrature/7765)

<div class="topic-metadata">

**Author:** [@Sagues](https://discourse.vtk.org/u/Sagues)\
**Replies:** 0\
**Last updated:** [February 3, 2022, 1:02pm UTC](https://discourse.vtk.org/t/how-to-interpolate-array-data-using-gauss-points-quadrature/7765 "2022-02-03T13:02:11Z")

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I need to interpolate a result (stress) using gauss points. I understand that I should use Quadrature Scheme. I’ve created a quadrature definition: vtkNew gauss\_points\_triangle; gauss\_points\_triangle-\>Initialize(VTK\_…

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## [TypeError: Cannot read properties of undefined (reading 'traverse')](https://discourse.vtk.org/t/typeerror-cannot-read-properties-of-undefined-reading-traverse/7803)

<div class="topic-metadata">

**Author:** [@Kevin\_Sweeney](https://discourse.vtk.org/u/Kevin_Sweeney)\
**Replies:** 12\
**Last updated:** [February 14, 2022, 9:40am UTC](https://discourse.vtk.org/t/typeerror-cannot-read-properties-of-undefined-reading-traverse/7803 "2022-02-14T09:40:03Z")

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Since yesterday I am getting the following error. TypeError: Cannot read properties of undefined (reading 'traverse') I cannot see anything that I have changed in the code for this to occur. I have also gone so far as …

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## [NEED HELP~ a bug in linux](https://discourse.vtk.org/t/need-help-a-bug-in-linux/7837)

<div class="topic-metadata">

**Author:** [@Clifford](https://discourse.vtk.org/u/Clifford)\
**Replies:** 0\
**Last updated:** [February 14, 2022, 8:34am UTC](https://discourse.vtk.org/t/need-help-a-bug-in-linux/7837 "2022-02-14T08:34:56Z")

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When I run a python program (use vtk) in my pc, it works successfully, however, when I post it on my server then comes with this error, does anybody knows how to fix it? Thanks so much! I truly have no idea with this. …

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## [Does vtk libraries need to add as per dependency in CMake ?](https://discourse.vtk.org/t/does-vtk-libraries-need-to-add-as-per-dependency-in-cmake/7825)

<div class="topic-metadata">

**Author:** [@shrikant](https://discourse.vtk.org/u/shrikant)\
**Replies:** 1\
**Last updated:** [February 13, 2022, 1:25pm UTC](https://discourse.vtk.org/t/does-vtk-libraries-need-to-add-as-per-dependency-in-cmake/7825 "2022-02-13T13:25:06Z")

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Dear all, I’m working with docker which built vtk7.1. I am seeing my project built successfully but while linking vtk libs it gives error about not finding some reference. I have all required vtk lib added in cmake. So…

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## [calculate the signed distance field of enclosed surface with vtkImplicitPolyDataDistance](https://discourse.vtk.org/t/calculate-the-signed-distance-field-of-enclosed-surface-with-vtkimplicitpolydatadistance/7818)

<div class="topic-metadata">

**Author:** [@xianger.qi](https://discourse.vtk.org/u/xianger.qi)\
**Replies:** 1\
**Last updated:** [February 11, 2022, 2:49pm UTC](https://discourse.vtk.org/t/calculate-the-signed-distance-field-of-enclosed-surface-with-vtkimplicitpolydatadistance/7818 "2022-02-11T14:49:37Z")

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Hi guys~ I want to calculate the signed distance field of a polydata, which has about 70000 points and 140000 cells, AND i set the sampling dimension with 100 \* 100 \* 100. It takes more than 60 seconds, is there existin…

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## [Named algorithms](https://discourse.vtk.org/t/named-algorithms/7759)

<div class="topic-metadata">

**Author:** [@andreasbuykx](https://discourse.vtk.org/u/andreasbuykx)\
**Replies:** 19\
**Last updated:** [February 11, 2022, 11:30am UTC](https://discourse.vtk.org/t/named-algorithms/7759 "2022-02-11T11:30:22Z")

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Error messages from pipelines indicate algorithms by their ptr address and class name. With complex pipelines this is usually insufficient to identify the algorithm that sends the message. It would be very helpful if alg…

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## [I found memory leak!!!](https://discourse.vtk.org/t/i-found-memory-leak/7815)

<div class="topic-metadata">

**Author:** [@MincheolKim](https://discourse.vtk.org/u/MincheolKim)\
**Replies:** 3\
**Last updated:** [February 11, 2022, 11:01am UTC](https://discourse.vtk.org/t/i-found-memory-leak/7815 "2022-02-11T11:01:33Z")

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I find a problem and fixed it. The code is below. I think that you can find what is problem. Please update it in the next version. int vtkDataSetSurfaceFilter::UnstructuredGridExecute in vtkDataSetSurfaceFilter.cxx …

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## [vtkVolume is not rendered when RenderPass is set (vtkSSAOPass)](https://discourse.vtk.org/t/vtkvolume-is-not-rendered-when-renderpass-is-set-vtkssaopass/7795)

<div class="topic-metadata">

**Author:** [@Daniel](https://discourse.vtk.org/u/Daniel)\
**Replies:** 8\
**Last updated:** [February 11, 2022, 8:51am UTC](https://discourse.vtk.org/t/vtkvolume-is-not-rendered-when-renderpass-is-set-vtkssaopass/7795 "2022-02-11T08:51:41Z")

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Hi @all, I’m experimenting around with vtkSSAOPass right now. I noticed that when I assign it to my renderer via ‘.SetPass(…)’, no vtkVolume objects are displayed. If I remove the assignment, the volume object is disp…

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## [egl rendering problem](https://discourse.vtk.org/t/egl-rendering-problem/7816)

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**Author:** [@yuxing55555](https://discourse.vtk.org/u/yuxing55555)\
**Replies:** 0\
**Last updated:** [February 11, 2022, 6:21am UTC](https://discourse.vtk.org/t/egl-rendering-problem/7816 "2022-02-11T06:21:26Z")

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I used vtk9.0.0 to use egl rendering to add the same actor to two windows, and found that the window that added the actor first could not render the added actor. #include \<vtkActor.h\> #include \<vtkCamera.h\> #include \<v…

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## [Mysterious points found when clipping a Delaunay filtered model](https://discourse.vtk.org/t/mysterious-points-found-when-clipping-a-delaunay-filtered-model/7805)

<div class="topic-metadata">

**Author:** [@dwventer](https://discourse.vtk.org/u/dwventer)\
**Replies:** 1\
**Last updated:** [February 11, 2022, 4:22am UTC](https://discourse.vtk.org/t/mysterious-points-found-when-clipping-a-delaunay-filtered-model/7805 "2022-02-11T04:22:21Z")

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Hi, I have a strange problem that I do not understand why it is happening. I have a ply file model that I crop to a small section using vtkClipPolyData and vtkPlanes. This is the resulting clipped image: I then run a…

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## [Calculating the circumference from cross sectional cut](https://discourse.vtk.org/t/calculating-the-circumference-from-cross-sectional-cut/7793)

<div class="topic-metadata">

**Author:** [@dwventer](https://discourse.vtk.org/u/dwventer)\
**Replies:** 2\
**Last updated:** [February 11, 2022, 4:13am UTC](https://discourse.vtk.org/t/calculating-the-circumference-from-cross-sectional-cut/7793 "2022-02-11T04:13:14Z")

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Hello, I’m using a vtkCutter to cut a cross-section from a poly data object using a vtkPlane as the cut function. The result is a disc-like shape seen below: I can use vtkMassProperties and get the surface area of th…

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## [Rendering/interaction issues with VTK 8.2 (Java) + JOGL on Windows](https://discourse.vtk.org/t/rendering-interaction-issues-with-vtk-8-2-java-jogl-on-windows/2781)

<div class="topic-metadata">

**Author:** [@Marco](https://discourse.vtk.org/u/Marco)\
**Replies:** 28\
**Last updated:** [February 10, 2022, 2:48pm UTC](https://discourse.vtk.org/t/rendering-interaction-issues-with-vtk-8-2-java-jogl-on-windows/2781 "2022-02-10T14:48:28Z")

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Hi all. I am using VTK 8.2 from a Java application. I am trying to use JOGL as a mechanism to have VTK render within my Java application, in the effort of having a cross-platform rendering pipeline working also under M…

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## [suppressing clang-tidy warnings from macros](https://discourse.vtk.org/t/suppressing-clang-tidy-warnings-from-macros/7807)

<div class="topic-metadata">

**Author:** [@andreasbuykx](https://discourse.vtk.org/u/andreasbuykx)\
**Replies:** 1\
**Last updated:** [February 10, 2022, 11:05am UTC](https://discourse.vtk.org/t/suppressing-clang-tidy-warnings-from-macros/7807 "2022-02-10T11:05:51Z")

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Some VTK warnings cause clang-tidy warnings in our code. For example, the SafeDownCast method implemented by the vtkTypeMacro causes a warning suggesting to use dynamic\_cast instead of static\_cast. This warning is unnec…

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## [A possible bug for vtkPicker](https://discourse.vtk.org/t/a-possible-bug-for-vtkpicker/7801)

<div class="topic-metadata">

**Author:** [@zhang-qiang-github](https://discourse.vtk.org/u/zhang-qiang-github)\
**Replies:** 2\
**Last updated:** [February 10, 2022, 6:08am UTC](https://discourse.vtk.org/t/a-possible-bug-for-vtkpicker/7801 "2022-02-10T06:08:05Z")

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I am using vtkCellPicker in my project. In some situation, the vtkCellPicker do not work. For example: import vtkmodules.all as vtk polyData = vtk.vtkPolyData() polyData.SetPoints(vtk.vtkPoints()) polyData.SetVerts(vt…

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## [Does vtkCellPicker conside point size?](https://discourse.vtk.org/t/does-vtkcellpicker-conside-point-size/7802)

<div class="topic-metadata">

**Author:** [@zhang-qiang-github](https://discourse.vtk.org/u/zhang-qiang-github)\
**Replies:** 2\
**Last updated:** [February 10, 2022, 1:20am UTC](https://discourse.vtk.org/t/does-vtkcellpicker-conside-point-size/7802 "2022-02-10T01:20:59Z")

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Please have a look for the following code: import vtkmodules.all as vtk polyData = vtk.vtkPolyData() polyData.SetPoints(vtk.vtkPoints()) polyData.SetVerts(vtk.vtkCellArray()) polyData.GetPoints().InsertNextPoint(1, 1…

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## [How to get the transformation values after applying vtkProcrustesAlignmentFilter](https://discourse.vtk.org/t/how-to-get-the-transformation-values-after-applying-vtkprocrustesalignmentfilter/7776)

<div class="topic-metadata">

**Author:** [@dalbenzioG](https://discourse.vtk.org/u/dalbenzioG)\
**Replies:** 8\
**Last updated:** [February 9, 2022, 10:04pm UTC](https://discourse.vtk.org/t/how-to-get-the-transformation-values-after-applying-vtkprocrustesalignmentfilter/7776 "2022-02-09T22:04:28Z")

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Hello, I am using vtkProcrustesAlignmentFilter to align two polydata to their mutual mean. After applying this filter, is it possible to get the information of their transformation values -rotation and translation in pa…

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## [vtkTextActor doesn't show multiple lines](https://discourse.vtk.org/t/vtktextactor-doesnt-show-multiple-lines/3482)

<div class="topic-metadata">

**Author:** [@Marcin\_Krotkiewski](https://discourse.vtk.org/u/Marcin_Krotkiewski)\
**Replies:** 6\
**Last updated:** [February 9, 2022, 8:57pm UTC](https://discourse.vtk.org/t/vtktextactor-doesnt-show-multiple-lines/3482 "2022-02-09T20:57:31Z")

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I am using VTK 9 through the Java bindings. It seems that I cannot force the vtkTextActor to display multiple lines of text. Instead, the newline character “\\n” is displayed literally (attached pic). The same is true for…

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## [I want to use VTK on Android.](https://discourse.vtk.org/t/i-want-to-use-vtk-on-android/945)

<div class="topic-metadata">

**Author:** [@ruanwenfeng](https://discourse.vtk.org/u/ruanwenfeng)\
**Replies:** 9\
**Last updated:** [February 9, 2022, 4:27pm UTC](https://discourse.vtk.org/t/i-want-to-use-vtk-on-android/945 "2022-02-09T16:27:54Z")

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\[10/1033\] Building CXX object IO/Export/CMakeFiles/vtkIOExport.dir/vtkGL2PSExporter.cxx.o FAILED: IO/Export/CMakeFiles/vtkIOExport.dir/vtkGL2PSExporter.cxx.o D:\\Android\\ndk-bundle\\toolchains\\llvm\\prebuilt\\windows-x86\_6…

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## [Difficulty in resizing/moving QDockWidgets in a PyQt5 app that contains a QVTKRenderWindowInteractor, on MacOS only.](https://discourse.vtk.org/t/difficulty-in-resizing-moving-qdockwidgets-in-a-pyqt5-app-that-contains-a-qvtkrenderwindowinteractor-on-macos-only/7763)

<div class="topic-metadata">

**Author:** [@p-j-smith](https://discourse.vtk.org/u/p-j-smith)\
**Replies:** 0\
**Last updated:** [February 3, 2022, 11:51am UTC](https://discourse.vtk.org/t/difficulty-in-resizing-moving-qdockwidgets-in-a-pyqt5-app-that-contains-a-qvtkrenderwindowinteractor-on-macos-only/7763 "2022-02-03T11:51:51Z")

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Hi, I’m building an application using PyQt5 that contains a QVTKRenderWindowInteractor widget within a QDockWidget. On MacOS, adding the QVTKRenderWindowInteractor makes it very difficult to resize or move the docks. H…

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## [ResliceCursorWidget that display the locations in .VTK file](https://discourse.vtk.org/t/reslicecursorwidget-that-display-the-locations-in-vtk-file/7764)

<div class="topic-metadata">

**Author:** [@stoune](https://discourse.vtk.org/u/stoune)\
**Replies:** 5\
**Last updated:** [February 4, 2022, 11:22pm UTC](https://discourse.vtk.org/t/reslicecursorwidget-that-display-the-locations-in-vtk-file/7764 "2022-02-04T23:22:15Z")

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Hey, I’m using ResliceCursorWidget to dispay the 3 directions of the brain slices (.VTI file) like in the example in the official website, I need the last container to show the 3D VTK actor and a little sphere in it…

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## [Force scalarBarActor Rerender](https://discourse.vtk.org/t/force-scalarbaractor-rerender/6487)

<div class="topic-metadata">

**Author:** [@Nicolas\_Schmidt](https://discourse.vtk.org/u/Nicolas_Schmidt)\
**Replies:** 1\
**Last updated:** [February 9, 2022, 12:46am UTC](https://discourse.vtk.org/t/force-scalarbaractor-rerender/6487 "2022-02-09T00:46:03Z")

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Is there a way to force scalarBarActor text labels to render? Strangely it seems like they only render after a mouseMove event? This is both when created initially and after calling setAxisLabel(). I’ve tried calling: …

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## [Proper use of vtkImageReslice?](https://discourse.vtk.org/t/proper-use-of-vtkimagereslice/7797)

<div class="topic-metadata">

**Author:** [@MJJ](https://discourse.vtk.org/u/MJJ)\
**Replies:** 0\
**Last updated:** [February 8, 2022, 10:24pm UTC](https://discourse.vtk.org/t/proper-use-of-vtkimagereslice/7797 "2022-02-08T22:24:19Z")

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I have a vtkImageData called img that I want to use the vtkImageReslice algorithm on. I want to reslice this image data to create a subimage that has its voxels aligned to a different coordinate system. To do this i am…

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## [How to set color and opacity transfer functions for a colored Tiff Volume](https://discourse.vtk.org/t/how-to-set-color-and-opacity-transfer-functions-for-a-colored-tiff-volume/7767)

<div class="topic-metadata">

**Author:** [@totte\_karlsson](https://discourse.vtk.org/u/totte_karlsson)\
**Replies:** 2\
**Last updated:** [February 8, 2022, 6:38pm UTC](https://discourse.vtk.org/t/how-to-set-color-and-opacity-transfer-functions-for-a-colored-tiff-volume/7767 "2022-02-08T18:38:39Z")

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Hello, We are working on a Neuron tracing application. At this stage, visualizing neuron model data (as simple polylines and spheres for the soma) works nicely. We are now at a stage where we want to look at the neuron…

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## [How to get hovering event with vtkInteractorStyle ?](https://discourse.vtk.org/t/how-to-get-hovering-event-with-vtkinteractorstyle/7687)

<div class="topic-metadata">

**Author:** [@Julienchz](https://discourse.vtk.org/u/Julienchz)\
**Replies:** 12\
**Last updated:** [February 8, 2022, 2:00pm UTC](https://discourse.vtk.org/t/how-to-get-hovering-event-with-vtkinteractorstyle/7687 "2022-02-08T14:00:11Z")

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Hello everyone, I would like to interact with a vtkRenderer to pick object when I am hovering an object. Unfortunately onMouseMove (from vtkInteractorStyle) works only when a real click happens. Is there a way to have m…

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## [Object is clipped during rotation + zooming](https://discourse.vtk.org/t/object-is-clipped-during-rotation-zooming/7794)

<div class="topic-metadata">

**Author:** [@Daniel](https://discourse.vtk.org/u/Daniel)\
**Replies:** 1\
**Last updated:** [February 8, 2022, 12:46pm UTC](https://discourse.vtk.org/t/object-is-clipped-during-rotation-zooming/7794 "2022-02-08T12:46:55Z")

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Hi there, after importing objects into my view and then moving the camera (rotating and zooming in), the object is clipped. Especially if it is viewed from the right or bottom. See image gallery. I would have guesse…

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## [How to display the direction of the slices?](https://discourse.vtk.org/t/how-to-display-the-direction-of-the-slices/7773)

<div class="topic-metadata">

**Author:** [@dexter](https://discourse.vtk.org/u/dexter)\
**Replies:** 4\
**Last updated:** [February 8, 2022, 10:05am UTC](https://discourse.vtk.org/t/how-to-display-the-direction-of-the-slices/7773 "2022-02-08T10:05:15Z")

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Hey I’m using ResliceCursorWidget to display an MPR viewer like in the example in the website: I need to display the directions (Right- Left- Below -Above- Posterior, Anterior ) in each View of the 3 views, Like this…

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## [Can I compile VTk 8.2.0 without qt?](https://discourse.vtk.org/t/can-i-compile-vtk-8-2-0-without-qt/7769)

<div class="topic-metadata">

**Author:** [@critchey](https://discourse.vtk.org/u/critchey)\
**Replies:** 4\
**Last updated:** [February 8, 2022, 5:48am UTC](https://discourse.vtk.org/t/can-i-compile-vtk-8-2-0-without-qt/7769 "2022-02-08T05:48:55Z")

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I’ve got vtk compiled using the standard cmake flags on osx, but it appears the dynlib files are linked to qt. I gave a look through the flags in ccmake, even the “advanced” flags and options like Module\_vtkGUISupportQt …

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## [Setting PATH environment variables for VTK build tree on Windows](https://discourse.vtk.org/t/setting-path-environment-variables-for-vtk-build-tree-on-windows/7788)

<div class="topic-metadata">

**Author:** [@amaclean](https://discourse.vtk.org/u/amaclean)\
**Replies:** 4\
**Last updated:** [February 8, 2022, 12:14am UTC](https://discourse.vtk.org/t/setting-path-environment-variables-for-vtk-build-tree-on-windows/7788 "2022-02-08T00:14:51Z")

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Ok I have solved the not finding numpy issue in the case of vtkpython. You have to add the path in the virtual environment path (\\Lib\\site-packages) to %PYTHONPATH% to get it.

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