# Latest

**URL:** https://discourse.vtk.org/latest.md?page=229

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

**Page:** 230

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## [How to have split normals on the boundary of a contour?](https://discourse.vtk.org/t/how-to-have-split-normals-on-the-boundary-of-a-contour/2301)

<div class="topic-metadata">

**Author:** [@Tim\_Hutton](https://discourse.vtk.org/u/Tim_Hutton)\
**Replies:** 0\
**Last updated:** [December 17, 2019, 3:45pm UTC](https://discourse.vtk.org/t/how-to-have-split-normals-on-the-boundary-of-a-contour/2301 "2019-12-17T15:45:37Z")

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Here’s the issue, and an image: https://github.com/GollyGang/ready/issues/47 My pipeline is vtkImageConstantPad -\> vtkContourFilter where the padding is used to add a cap on the open ends, to hide the interior sections …

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## [How Can I Pick from an Image that is Not the Top Layer in a vtkImageStack?](https://discourse.vtk.org/t/how-can-i-pick-from-an-image-that-is-not-the-top-layer-in-a-vtkimagestack/2278)

<div class="topic-metadata">

**Author:** [@MichelleKline](https://discourse.vtk.org/u/MichelleKline)\
**Replies:** 2\
**Last updated:** [December 16, 2019, 5:50pm UTC](https://discourse.vtk.org/t/how-can-i-pick-from-an-image-that-is-not-the-top-layer-in-a-vtkimagestack/2278 "2019-12-16T17:50:38Z")

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Hello, In my application, I am rendering two images overlayed on one another. The images are vtkImageSlice(s) and I use a vtkImageStack to store both images. The topmost image is cropped in such a way that it’s exent …

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## [How to compile VTK 8.2.0 with gcc-7 and Qt 5.9.1 on MacOS 10.14?](https://discourse.vtk.org/t/how-to-compile-vtk-8-2-0-with-gcc-7-and-qt-5-9-1-on-macos-10-14/2194)

<div class="topic-metadata">

**Author:** [@benjaminwelle](https://discourse.vtk.org/u/benjaminwelle)\
**Replies:** 15\
**Last updated:** [December 16, 2019, 1:06pm UTC](https://discourse.vtk.org/t/how-to-compile-vtk-8-2-0-with-gcc-7-and-qt-5-9-1-on-macos-10-14/2194 "2019-12-16T13:06:19Z")

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I am trying hard since a while already to compile VTK 8.2.0 with CMake 3.16.0, Qt 5.9.1 and MacPorts gcc7 7.4.0\_3 on MacOS Mojave, i.e. with MacOSX10.14.sdk (Xcode), but I can’t get it to work. I had the same problems al…

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## [vtkPropPicker not working in Java wrapper after upgrade to 8.2.0](https://discourse.vtk.org/t/vtkproppicker-not-working-in-java-wrapper-after-upgrade-to-8-2-0/2121)

<div class="topic-metadata">

**Author:** [@mat127](https://discourse.vtk.org/u/mat127)\
**Replies:** 1\
**Last updated:** [December 16, 2019, 9:00am UTC](https://discourse.vtk.org/t/vtkproppicker-not-working-in-java-wrapper-after-upgrade-to-8-2-0/2121 "2019-12-16T09:00:50Z")

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Hi, I use the VTK library through the Java wrapper. After upgrading to 8.2.0 my code using the vtkPropPicker does not work any more (in 8.1.1 was ok). The renderer where I do the picking contains a vtkAssembly containi…

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## [How can I pick a modified polydata?(complete code supplied)](https://discourse.vtk.org/t/how-can-i-pick-a-modified-polydata-complete-code-supplied/2269)

<div class="topic-metadata">

**Author:** [@tdchen](https://discourse.vtk.org/u/tdchen)\
**Replies:** 1\
**Last updated:** [December 16, 2019, 1:45am UTC](https://discourse.vtk.org/t/how-can-i-pick-a-modified-polydata-complete-code-supplied/2269 "2019-12-16T01:45:41Z")

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The following program display a triangle firstly. When you hit the triangle, it splits into 2 triangles. The problem is: after splitting, you can’t hit the large triangle. What is the reason? Hope your reply. #inclu…

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## [Why does vtkConnectivityFilter not preserve point or cell data?](https://discourse.vtk.org/t/why-does-vtkconnectivityfilter-not-preserve-point-or-cell-data/2284)

<div class="topic-metadata">

**Author:** [@normanius](https://discourse.vtk.org/u/normanius)\
**Replies:** 0\
**Last updated:** [December 15, 2019, 11:13pm UTC](https://discourse.vtk.org/t/why-does-vtkconnectivityfilter-not-preserve-point-or-cell-data/2284 "2019-12-15T23:13:42Z")

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Dear all I noticed that vtkPolyDataConnectivityFilter doesn’t preserve point or cell data. Any particular reason for this behavior? I see that the connectivity filter may discard points and cells. Because the remaining…

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## [How can I display the contour color (inner model](https://discourse.vtk.org/t/how-can-i-display-the-contour-color-inner-model/2283)

<div class="topic-metadata">

**Author:** [@1115](https://discourse.vtk.org/u/1115)\
**Replies:** 0\
**Last updated:** [December 15, 2019, 6:53am UTC](https://discourse.vtk.org/t/how-can-i-display-the-contour-color-inner-model/2283 "2019-12-15T06:53:21Z")

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Left : VTK, Right : OpenGL I want to display the contour like right(opengl)

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## [How can I achieve transparent out-of-range colors with the vtk color transfer function?](https://discourse.vtk.org/t/how-can-i-achieve-transparent-out-of-range-colors-with-the-vtk-color-transfer-function/2257)

<div class="topic-metadata">

**Author:** [@MichelleKline](https://discourse.vtk.org/u/MichelleKline)\
**Replies:** 6\
**Last updated:** [December 13, 2019, 10:27pm UTC](https://discourse.vtk.org/t/how-can-i-achieve-transparent-out-of-range-colors-with-the-vtk-color-transfer-function/2257 "2019-12-13T22:27:17Z")

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Hello, I am attempting to use the vtkColorTransferFunction or the vtkDiscretizableColorTransferFunction class to create a custom colormap for my vtk-based application. I am using this class in lieu of the vtkLookupTabl…

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## [can vtk use mutltiple GPU together](https://discourse.vtk.org/t/can-vtk-use-mutltiple-gpu-together/2275)

<div class="topic-metadata">

**Author:** [@baoyun](https://discourse.vtk.org/u/baoyun)\
**Replies:** 0\
**Last updated:** [December 13, 2019, 7:31pm UTC](https://discourse.vtk.org/t/can-vtk-use-mutltiple-gpu-together/2275 "2019-12-13T19:31:49Z")

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If I want to use all my GPU to display many volumes at same time, try to utilize all available GPU memory. Can I do this using VTK? Thanks

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## [Move sphere along polyline](https://discourse.vtk.org/t/move-sphere-along-polyline/2225)

<div class="topic-metadata">

**Author:** [@Romain](https://discourse.vtk.org/u/Romain)\
**Replies:** 3\
**Last updated:** [December 13, 2019, 2:36pm UTC](https://discourse.vtk.org/t/move-sphere-along-polyline/2225 "2019-12-13T14:36:49Z")

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Hi everyone, I try to move a sphere along a Polyline. I use vtkPropPicker to get the current mouse position then I use vtkCellLocator to found the closest point from the picked position to the Polyline using FindCloses…

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## [Real time viewing of geometry data from a source file](https://discourse.vtk.org/t/real-time-viewing-of-geometry-data-from-a-source-file/2272)

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**Author:** [@jk7070](https://discourse.vtk.org/u/jk7070)\
**Replies:** 0\
**Last updated:** [December 13, 2019, 2:04pm UTC](https://discourse.vtk.org/t/real-time-viewing-of-geometry-data-from-a-source-file/2272 "2019-12-13T14:04:15Z")

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Hi, I have what I think is a simple question. I have a simple shape, call it a Quad. The points of the Quad are initially read from a file, in this case an excel workbook. What I want is to be able to update the points i…

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## [Scaling to 0.001 produces unexpected result](https://discourse.vtk.org/t/scaling-to-0-001-produces-unexpected-result/2248)

<div class="topic-metadata">

**Author:** [@idhamari](https://discourse.vtk.org/u/idhamari)\
**Replies:** 2\
**Last updated:** [December 13, 2019, 11:40am UTC](https://discourse.vtk.org/t/scaling-to-0-001-produces-unexpected-result/2248 "2019-12-13T11:40:27Z")

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Dear all I am trying to scale a mesh to 0.001 but I get a mesh that does not look like the original one. Here is the code I used: reader = vtk.vtkSTLReader() reader.SetFileName(inputFilename) reader.Update…

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## [WindowToImageFilter reading old buffer images](https://discourse.vtk.org/t/windowtoimagefilter-reading-old-buffer-images/2267)

<div class="topic-metadata">

**Author:** [@sandress](https://discourse.vtk.org/u/sandress)\
**Replies:** 0\
**Last updated:** [December 13, 2019, 12:35am UTC](https://discourse.vtk.org/t/windowtoimagefilter-reading-old-buffer-images/2267 "2019-12-13T00:35:14Z")

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I’m using VTK to create a series of DRR images using offscreen rendering and the vtkWindowToImageFilter. Therefore I’m randomly changing the Camera position and save this transform to the then generated DRR image. Howev…

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## [Piece ID from vtkXMLPUnstructuredGridReader](https://discourse.vtk.org/t/piece-id-from-vtkxmlpunstructuredgridreader/2265)

<div class="topic-metadata">

**Author:** [@banesullivan](https://discourse.vtk.org/u/banesullivan)\
**Replies:** 1\
**Last updated:** [December 12, 2019, 11:32pm UTC](https://discourse.vtk.org/t/piece-id-from-vtkxmlpunstructuredgridreader/2265 "2019-12-12T23:32:48Z")

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When using the parallel VTU file reader (vtkXMLPUnstructuredGridReader), is there a way to have the reader automatically add an array corresponding to the piece of the mesh? (e.g. integers from 0 to NumberOfPeices I hav…

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## [10 bit per channel RGB](https://discourse.vtk.org/t/10-bit-per-channel-rgb/2262)

<div class="topic-metadata">

**Author:** [@iheartvtoolkit](https://discourse.vtk.org/u/iheartvtoolkit)\
**Replies:** 2\
**Last updated:** [December 12, 2019, 3:28pm UTC](https://discourse.vtk.org/t/10-bit-per-channel-rgb/2262 "2019-12-12T15:28:08Z")

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Hi, I am wondering if there are any low/high-level options to change color-manipulating classes such as vtkLookupTable, vtkImageMapToColors, etc, to use 10 bpc instead of 8? Background: Trying to pass 10 bpc QC tests. I…

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## [Is GetConnectivityArray missing from vtkCellArray class in Python package?](https://discourse.vtk.org/t/is-getconnectivityarray-missing-from-vtkcellarray-class-in-python-package/2250)

<div class="topic-metadata">

**Author:** [@pcs](https://discourse.vtk.org/u/pcs)\
**Replies:** 2\
**Last updated:** [December 12, 2019, 2:50pm UTC](https://discourse.vtk.org/t/is-getconnectivityarray-missing-from-vtkcellarray-class-in-python-package/2250 "2019-12-12T14:50:25Z")

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I have an XML unstructured grid with polyhedral elements and would like to read it using Python for post-processing analysis of a simulation. I am using Python 3.7.4 and vtk 8.1.2. I can read the file with vtkXMLUnstruc…

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## [Reading csv and display it as 2D image](https://discourse.vtk.org/t/reading-csv-and-display-it-as-2d-image/2263)

<div class="topic-metadata">

**Author:** [@Lavanya](https://discourse.vtk.org/u/Lavanya)\
**Replies:** 0\
**Last updated:** [December 12, 2019, 10:30am UTC](https://discourse.vtk.org/t/reading-csv-and-display-it-as-2d-image/2263 "2019-12-12T10:30:47Z")

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Hi everyone, I am trying to read a csv file and display it as image. I’m very new to C++ and Vtk. The csv file has following data: 1 2 3 4 10 20 30 40 50 60 70 80 Any suggestions please??

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## [Synchronize windows level of vtkResliceImageViewer with multiple renderers](https://discourse.vtk.org/t/synchronize-windows-level-of-vtkresliceimageviewer-with-multiple-renderers/2260)

<div class="topic-metadata">

**Author:** [@zandarina](https://discourse.vtk.org/u/zandarina)\
**Replies:** 0\
**Last updated:** [December 12, 2019, 9:57am UTC](https://discourse.vtk.org/t/synchronize-windows-level-of-vtkresliceimageviewer-with-multiple-renderers/2260 "2019-12-12T09:57:41Z")

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Hi !! I have N slices in a layout shown in a single windows at the same time all slices. This layout is a vtkResliceImageViewer and each slice is a new renderer that is set up in a part of the viewport from the same vi…

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## [Convert 2D ultrasound image to 3D](https://discourse.vtk.org/t/convert-2d-ultrasound-image-to-3d/1614)

<div class="topic-metadata">

**Author:** [@Qiangyun\_li](https://discourse.vtk.org/u/Qiangyun_li)\
**Replies:** 5\
**Last updated:** [December 12, 2019, 5:59am UTC](https://discourse.vtk.org/t/convert-2d-ultrasound-image-to-3d/1614 "2019-12-12T05:59:57Z")

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I have 3D matrix and the pixel spacing about volume , how can l get volume render.

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## [How to triangulate a surface from point cloud](https://discourse.vtk.org/t/how-to-triangulate-a-surface-from-point-cloud/2240)

<div class="topic-metadata">

**Author:** [@T4mmi](https://discourse.vtk.org/u/T4mmi)\
**Replies:** 5\
**Last updated:** [December 12, 2019, 5:39am UTC](https://discourse.vtk.org/t/how-to-triangulate-a-surface-from-point-cloud/2240 "2019-12-12T05:39:01Z")

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Hi all, Quite new to vtk and meshing in general (got a raster processing background). I understand the concept of mesh (and polydata) as a tuple of : vertices/points (i.e. space coordinates): (x,y,z) in 3D cells (i.e…

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## [How to get "connectivity", "offsets", "faces", "faceoffsets" array from "Cell" in unstructured polyhedral grid](https://discourse.vtk.org/t/how-to-get-connectivity-offsets-faces-faceoffsets-array-from-cell-in-unstructured-polyhedral-grid/2244)

<div class="topic-metadata">

**Author:** [@pcs](https://discourse.vtk.org/u/pcs)\
**Replies:** 2\
**Last updated:** [December 12, 2019, 5:27am UTC](https://discourse.vtk.org/t/how-to-get-connectivity-offsets-faces-faceoffsets-array-from-cell-in-unstructured-polyhedral-grid/2244 "2019-12-12T05:27:50Z")

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I have an XML unstructured grid with polyhedral elements and would like to read it using Python for post-processing analysis of a simulation. I can read the file with vtkXMLUnstructuredGridReader and successfully read so…

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## [Obtaining the CellData of a given Cell](https://discourse.vtk.org/t/obtaining-the-celldata-of-a-given-cell/2210)

<div class="topic-metadata">

**Author:** [@balborian](https://discourse.vtk.org/u/balborian)\
**Replies:** 1\
**Last updated:** [December 11, 2019, 11:01pm UTC](https://discourse.vtk.org/t/obtaining-the-celldata-of-a-given-cell/2210 "2019-12-11T23:01:39Z")

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Consider the code below: reader = PVDReader(FileName="./function.pvd") data = servermanager.Fetch(reader) cells = data.GetCells() cells.InitTraversal() cell\_data\_arr = data.GetCellData().GetArray(0) for i in range(c…

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## [Consistency of face orientation in vtkCell3D](https://discourse.vtk.org/t/consistency-of-face-orientation-in-vtkcell3d/2253)

<div class="topic-metadata">

**Author:** [@Yohann\_Bearzi](https://discourse.vtk.org/u/Yohann_Bearzi)\
**Replies:** 2\
**Last updated:** [December 11, 2019, 3:33pm UTC](https://discourse.vtk.org/t/consistency-of-face-orientation-in-vtkcell3d/2253 "2019-12-11T15:33:33Z")

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Hi everyone, vtkCell class has the method vtkCell::GetFaces, and vtkCell3D class has vtkCell3D::GetFacePoints on top of that. In general, one would want that the orientation of the output face would be consistent, i.e. …

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## [Create a vtkTexture from in-memory imagedata](https://discourse.vtk.org/t/create-a-vtktexture-from-in-memory-imagedata/2227)

<div class="topic-metadata">

**Author:** [@Michael\_Jackson](https://discourse.vtk.org/u/Michael_Jackson)\
**Replies:** 9\
**Last updated:** [December 11, 2019, 2:03pm UTC](https://discourse.vtk.org/t/create-a-vtktexture-from-in-memory-imagedata/2227 "2019-12-11T14:03:43Z")

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I am trying to create a vtkTexture for use on a Quad object. I have the data already existing in memory as an array of floating point values between about 0.3 and 0.93. I have created a vtkLookupTable to map from the val…

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## [Z-Buffer Values Problem with Camera](https://discourse.vtk.org/t/z-buffer-values-problem-with-camera/2224)

<div class="topic-metadata">

**Author:** [@Alex1](https://discourse.vtk.org/u/Alex1)\
**Replies:** 3\
**Last updated:** [December 11, 2019, 12:26pm UTC](https://discourse.vtk.org/t/z-buffer-values-problem-with-camera/2224 "2019-12-11T12:26:45Z")

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Hi all, I try to get the zBuffer Values from my vtkRenderWindow with renWin-\>GetZbufferData(x1,y1,x2,y2) and it works fine, if I print the Image to file I get this : But as soon as I add a Camera to my renderer it do…

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## [Simplification of Python modules, and things to watch for](https://discourse.vtk.org/t/simplification-of-python-modules-and-things-to-watch-for/2251)

<div class="topic-metadata">

**Author:** [@dgobbi](https://discourse.vtk.org/u/dgobbi)\
**Replies:** 1\
**Last updated:** [December 11, 2019, 11:47am UTC](https://discourse.vtk.org/t/simplification-of-python-modules-and-things-to-watch-for/2251 "2019-12-11T11:47:08Z")

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Hi All, This morning I merged a branch into master that changes the way that VTK’s Python modules are built and loaded. As you might recall, the vtk-python modules used to have three components: libvtkCommonCorePytho…

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## [Python test dashboard failures](https://discourse.vtk.org/t/python-test-dashboard-failures/2255)

<div class="topic-metadata">

**Author:** [@sankhesh](https://discourse.vtk.org/u/sankhesh)\
**Replies:** 2\
**Last updated:** [December 11, 2019, 9:41am UTC](https://discourse.vtk.org/t/python-test-dashboard-failures/2255 "2019-12-11T09:41:24Z")

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Hello, VTK merge requests with changes prior to 45c34233 might show multiple (~680) VTKPython dashboard failures. Per Ben, issuing Do: test --clean should clean it up. Best, Sankhesh

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## [AttributeError: 'module' object has no attribute 'vtkOBJWriter'](https://discourse.vtk.org/t/attributeerror-module-object-has-no-attribute-vtkobjwriter/2249)

<div class="topic-metadata">

**Author:** [@idhamari](https://discourse.vtk.org/u/idhamari)\
**Replies:** 2\
**Last updated:** [December 10, 2019, 5:05pm UTC](https://discourse.vtk.org/t/attributeerror-module-object-has-no-attribute-vtkobjwriter/2249 "2019-12-10T17:05:11Z")

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Dear all, Why I get an error saying this module is missing? Python 2.7.15+ (default, Oct 7 2019, 17:39:04) \[GCC 7.4.0\] on linux2 Type "help", "copyright", "credits" or "license" for more information. \>\>\> import vtk \>\>…

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## [Can't run some VTK examples in Qt](https://discourse.vtk.org/t/cant-run-some-vtk-examples-in-qt/2242)

<div class="topic-metadata">

**Author:** [@kerim](https://discourse.vtk.org/u/kerim)\
**Replies:** 7\
**Last updated:** [December 10, 2019, 4:02pm UTC](https://discourse.vtk.org/t/cant-run-some-vtk-examples-in-qt/2242 "2019-12-10T16:02:49Z")

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Hi, I installed VTK-8.2.0 from source on Windows x64 with MSVC x64. I upload CMakeCache from CMake GUI. I can run this example CylinderExample but I can’t run this ParametricKuenDemo. If I try to run this example I ge…

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## [attempt to render to unbound program](https://discourse.vtk.org/t/attempt-to-render-to-unbound-program/2216)

<div class="topic-metadata">

**Author:** [@aglv](https://discourse.vtk.org/u/aglv)\
**Replies:** 2\
**Last updated:** [December 10, 2019, 10:23am UTC](https://discourse.vtk.org/t/attempt-to-render-to-unbound-program/2216 "2019-12-10T10:23:06Z")

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The software I’m working on uses multiple vtkCocoaGLView instances to display stuff. Since updating to recent VTK versions from VTK 5, the rendering pipeline stops working when switching between windows. I tracked this …

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