# Latest

**URL:** https://discourse.vtk.org/latest.md?page=244

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

**Page:** 245

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## [apply filter multiple times](https://discourse.vtk.org/t/apply-filter-multiple-times/1300)

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**Author:** [@martin.genet](https://discourse.vtk.org/u/martin.genet)\
**Replies:** 0\
**Last updated:** [July 7, 2019, 1:16pm UTC](https://discourse.vtk.org/t/apply-filter-multiple-times/1300 "2019-07-07T13:16:48Z")

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Dear all: I am having some issue setting up a rather complex pipeline involving, but not exclusively, vtk objects and filters. I think basically the issue boils down to this: I create an unstructured grid with some vect…

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## [How to preserve array data with vtkClipPolyData?](https://discourse.vtk.org/t/how-to-preserve-array-data-with-vtkclippolydata/1271)

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**Author:** [@normanius](https://discourse.vtk.org/u/normanius)\
**Replies:** 3\
**Last updated:** [July 7, 2019, 11:21am UTC](https://discourse.vtk.org/t/how-to-preserve-array-data-with-vtkclippolydata/1271 "2019-07-07T11:21:48Z")

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I’m using vtkClipPolyData to clip a vtkPolyData object. Is it possible to preserve the array data stored in the source object? I noticed that after clipping, the output does not contain any point- or cell-data. If it’s …

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## [Is it possible to turn off triangles on vtkClipDataSet filter?](https://discourse.vtk.org/t/is-it-possible-to-turn-off-triangles-on-vtkclipdataset-filter/279)

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**Author:** [@banesullivan](https://discourse.vtk.org/u/banesullivan)\
**Replies:** 25\
**Last updated:** [July 6, 2019, 7:41pm UTC](https://discourse.vtk.org/t/is-it-possible-to-turn-off-triangles-on-vtkclipdataset-filter/279 "2019-07-06T19:41:37Z")

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Is it possible to turn off triangles when clipping a dataset via the vtk.vtkClipDataSet filter? The slicing filter (vtk.vtkCutter) has an awesome GenerateTrianglesOff() method… is there an equivalent for the clip filter? …

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## [VTU file error visualize on paraview](https://discourse.vtk.org/t/vtu-file-error-visualize-on-paraview/1253)

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**Author:** [@Vaya\_Putra](https://discourse.vtk.org/u/Vaya_Putra)\
**Replies:** 3\
**Last updated:** [July 6, 2019, 2:30am UTC](https://discourse.vtk.org/t/vtu-file-error-visualize-on-paraview/1253 "2019-07-06T02:30:50Z")

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hi i create new file VTU file, but i can not visualize in paraview got some error Error parsing XML in stream at line 158, column 2, byte index 2505: mismatched tag Error parsing input file. ReadXMLInformation abort…

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## [CT opacity gradient piecewise function](https://discourse.vtk.org/t/ct-opacity-gradient-piecewise-function/1274)

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**Author:** [@socd06](https://discourse.vtk.org/u/socd06)\
**Replies:** 4\
**Last updated:** [July 5, 2019, 3:25pm UTC](https://discourse.vtk.org/t/ct-opacity-gradient-piecewise-function/1274 "2019-07-05T15:25:05Z")

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Hi, I’m going through examples from the textbook and user guide and I recently started working on https://lorensen.github.io/VTKExamples/site/Cxx/Medical/MedicalDemo4/ To volume render DICOM CT data. I can’t figure out…

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## [Remove collinear points from polyline](https://discourse.vtk.org/t/remove-collinear-points-from-polyline/1282)

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**Author:** [@lplavorante](https://discourse.vtk.org/u/lplavorante)\
**Replies:** 0\
**Last updated:** [July 5, 2019, 1:04pm UTC](https://discourse.vtk.org/t/remove-collinear-points-from-polyline/1282 "2019-07-05T13:04:46Z")

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Greetings! Does VTK provide a filter to remove collinear points from a polyline (stored as vtkPolyData)? Basically, my polylines contain contiguous collinear segments and I need to replace each such group with a single …

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## [Plot Individual Values for Each Cell](https://discourse.vtk.org/t/plot-individual-values-for-each-cell/1277)

<div class="topic-metadata">

**Author:** [@akaszynski](https://discourse.vtk.org/u/akaszynski)\
**Replies:** 0\
**Last updated:** [July 5, 2019, 8:13am UTC](https://discourse.vtk.org/t/plot-individual-values-for-each-cell/1277 "2019-07-05T08:13:35Z")

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I’d like to plot scalars that are individual for each cell and each point. To clarify, the number of scalars matches the (npoints\*ncells). Since this doesn’t match the number of cells or the number of points, you can’t…

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## [VTKChartLegend not movable](https://discourse.vtk.org/t/vtkchartlegend-not-movable/1237)

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**Author:** [@ChristopherWaters](https://discourse.vtk.org/u/ChristopherWaters)\
**Replies:** 1\
**Last updated:** [July 4, 2019, 2:43am UTC](https://discourse.vtk.org/t/vtkchartlegend-not-movable/1237 "2019-07-04T02:43:28Z")

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My VTKChartLegend is unmovable, even with this returning true: chart-\>GetLegend()-\>GetDragEnabled(); Everything else about my VTKChartXY is working, and the interactor seems to be fully functional except for this. I am…

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## [Problem in volume Rendering. Noise added automatically](https://discourse.vtk.org/t/problem-in-volume-rendering-noise-added-automatically/1235)

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**Author:** [@arefinster](https://discourse.vtk.org/u/arefinster)\
**Replies:** 4\
**Last updated:** [July 3, 2019, 7:23pm UTC](https://discourse.vtk.org/t/problem-in-volume-rendering-noise-added-automatically/1235 "2019-07-03T19:23:16Z")

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Hi, I have been trying to render a custom volume in vtk, but it is showing a lot of statics (random values). I have tried many options with no avail. Here is my code snippet. for (int k = 0; k \< existingVolDims\[2\]; k++…

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## [Get Point Array Data from an case file](https://discourse.vtk.org/t/get-point-array-data-from-an-case-file/1264)

<div class="topic-metadata">

**Author:** [@cvAIRteam](https://discourse.vtk.org/u/cvAIRteam)\
**Replies:** 0\
**Last updated:** [July 3, 2019, 4:50pm UTC](https://discourse.vtk.org/t/get-point-array-data-from-an-case-file/1264 "2019-07-03T16:50:27Z")

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Hello everyone, I am a vtk beginner. I use it with python. In a case file, there is a point array called “Velocity” and i would like to extract/get the data of this array. At the beginning, I process as follow: read…

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## [Opacity issue with point picking on surface](https://discourse.vtk.org/t/opacity-issue-with-point-picking-on-surface/1193)

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**Author:** [@kayarre](https://discourse.vtk.org/u/kayarre)\
**Replies:** 13\
**Last updated:** [July 3, 2019, 3:19pm UTC](https://discourse.vtk.org/t/opacity-issue-with-point-picking-on-surface/1193 "2019-07-03T15:19:43Z")

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I have edited a actor to have an opacity less than 1, such that I can see a second actor inside the first. There seems to be a weird behavior that I didn’t notice when the opacity was set to 1. When using an interacti…

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## [vtkExtractUnstructuredGrid does not return any points on Windows](https://discourse.vtk.org/t/vtkextractunstructuredgrid-does-not-return-any-points-on-windows/1164)

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**Author:** [@ataber](https://discourse.vtk.org/u/ataber)\
**Replies:** 13\
**Last updated:** [July 3, 2019, 12:57am UTC](https://discourse.vtk.org/t/vtkextractunstructuredgrid-does-not-return-any-points-on-windows/1164 "2019-07-03T00:57:06Z")

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The vtkExtractUnstructuredGrid class is awesome on Linux, where it successfully merges points for unstructured grids. However, on Windows, it returns 0 points with merging on. I have explicitly turned off all clipping so…

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## [Culling of Point Labels](https://discourse.vtk.org/t/culling-of-point-labels/1243)

<div class="topic-metadata">

**Author:** [@akaszynski](https://discourse.vtk.org/u/akaszynski)\
**Replies:** 3\
**Last updated:** [July 2, 2019, 7:04pm UTC](https://discourse.vtk.org/t/culling-of-point-labels/1243 "2019-07-02T19:04:29Z")

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Is there a way to cull or hide point labels when they are behind a mesh? There’s a good example of this phenomenon here at pyvista Issue 282. I’ve tried to use vtkLabelPlacementMapper instead of vtkLabeledDataMapper, b…

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## [Header-only vtk-derived class](https://discourse.vtk.org/t/header-only-vtk-derived-class/1254)

<div class="topic-metadata">

**Author:** [@tom](https://discourse.vtk.org/u/tom)\
**Replies:** 9\
**Last updated:** [July 2, 2019, 5:40pm UTC](https://discourse.vtk.org/t/header-only-vtk-derived-class/1254 "2019-07-02T17:40:41Z")

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Hi, I’m writing a few classes that derive from vtkSocketController. They have some things in common, so I’d like to write a small header-only abstract class for my other classes to inherit from. However, I’m having pr…

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## [VTK unstructured grid raw format in XML type](https://discourse.vtk.org/t/vtk-unstructured-grid-raw-format-in-xml-type/434)

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**Author:** [@Mini\_love](https://discourse.vtk.org/u/Mini_love)\
**Replies:** 10\
**Last updated:** [July 2, 2019, 4:49pm UTC](https://discourse.vtk.org/t/vtk-unstructured-grid-raw-format-in-xml-type/434 "2019-07-02T16:49:16Z")

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I am a newer of VTK, and I want to write a program to save my CFD results in Raw .vtu format. I find some examples from git-hub, but both of them don't work. I hope some one can help me. Do you have any Raw .vtu examp…

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## [vtkStreamTracer using regular grid?](https://discourse.vtk.org/t/vtkstreamtracer-using-regular-grid/1215)

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**Author:** [@Jesper\_Henriksen](https://discourse.vtk.org/u/Jesper_Henriksen)\
**Replies:** 1\
**Last updated:** [July 2, 2019, 11:41am UTC](https://discourse.vtk.org/t/vtkstreamtracer-using-regular-grid/1215 "2019-07-02T11:41:26Z")

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Hi guys, I’m having great trouble getting the vtkStreamTracer to show any traces from generated data (the original code used a vtkRTAnalyticSource to generate the data). It is probably some thing trivial but I have been…

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## [3d Render with vtkVolume error](https://discourse.vtk.org/t/3d-render-with-vtkvolume-error/1244)

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**Author:** [@pingdan](https://discourse.vtk.org/u/pingdan)\
**Replies:** 0\
**Last updated:** [July 2, 2019, 1:22am UTC](https://discourse.vtk.org/t/3d-render-with-vtkvolume-error/1244 "2019-07-02T01:22:39Z")

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ERROR: In D:\\ct\\VTK\\VTK-8.1.2\\Rendering\\OpenGL2\\vtkWin32OpenGLRenderWindow.cxx, line 227 vtkWin32OpenGLRenderWindow (000001F37C5C8A70): wglMakeCurrent failed in MakeCurrent(), error … many errors like this. how to so…

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## [Geometry Shader Implementation](https://discourse.vtk.org/t/geometry-shader-implementation/1189)

<div class="topic-metadata">

**Author:** [@Tharun](https://discourse.vtk.org/u/Tharun)\
**Replies:** 2\
**Last updated:** [July 1, 2019, 5:01pm UTC](https://discourse.vtk.org/t/geometry-shader-implementation/1189 "2019-07-01T17:01:43Z")

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Can someone please guide me on how to inject Geometry Shader Code?

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## [make cube a parent of camera](https://discourse.vtk.org/t/make-cube-a-parent-of-camera/1239)

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**Author:** [@svabhishek29](https://discourse.vtk.org/u/svabhishek29)\
**Replies:** 0\
**Last updated:** [July 1, 2019, 3:24pm UTC](https://discourse.vtk.org/t/make-cube-a-parent-of-camera/1239 "2019-07-01T15:24:34Z")

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hi, is it possible in vtk, to make an actor like a cube actor, a parent of the active camera? so that if i change the transform of the cube actor the camera relatively follows the cube with the same off set i had set i…

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## [Synchronize renderWindow, addObserver on vtkRenderWindowInteractor in vtk.js](https://discourse.vtk.org/t/synchronize-renderwindow-addobserver-on-vtkrenderwindowinteractor-in-vtk-js/1218)

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**Author:** [@PBrockmann](https://discourse.vtk.org/u/PBrockmann)\
**Replies:** 6\
**Last updated:** [June 30, 2019, 9:15pm UTC](https://discourse.vtk.org/t/synchronize-renderwindow-addobserver-on-vtkrenderwindowinteractor-in-vtk-js/1218 "2019-06-30T21:15:27Z")

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Hi, I would like to synchronize 2 renderWindows (or more). Any mouse move from one will be apply to the others. I have imagined to capture the camera from one renderWindow and then apply it to the other but I cannot …

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## [interactor stops after scaling volume](https://discourse.vtk.org/t/interactor-stops-after-scaling-volume/1223)

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**Author:** [@svabhishek29](https://discourse.vtk.org/u/svabhishek29)\
**Replies:** 2\
**Last updated:** [June 29, 2019, 8:37am UTC](https://discourse.vtk.org/t/interactor-stops-after-scaling-volume/1223 "2019-06-29T08:37:13Z")

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hi, i was experimenting with medical demo volume rendering example with my own nii file, i want to use the convention 1 unit = 1 meter so i scaled the volume by using vtk transform scale property and after the volume i…

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## [VTK 8.2 with Gallium Driver SWR fails with vtkOpenGLSphereMapper](https://discourse.vtk.org/t/vtk-8-2-with-gallium-driver-swr-fails-with-vtkopenglspheremapper/1206)

<div class="topic-metadata">

**Author:** [@psandana](https://discourse.vtk.org/u/psandana)\
**Replies:** 3\
**Last updated:** [June 28, 2019, 7:44pm UTC](https://discourse.vtk.org/t/vtk-8-2-with-gallium-driver-swr-fails-with-vtkopenglspheremapper/1206 "2019-06-28T19:44:50Z")

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Hi, I tried to use vtkAtoms which uses vtkOpenGLSphereMapper inside. On the new VTK 8.2 they are using a geometry shader. Using Mesa 17 with the llvmpipe driver works perfectly. But when changing to the SWR driver it fa…

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## [vtkStaticCellLocator FindClosestPoint?](https://discourse.vtk.org/t/vtkstaticcelllocator-findclosestpoint/1091)

<div class="topic-metadata">

**Author:** [@michal.wozniak](https://discourse.vtk.org/u/michal.wozniak)\
**Replies:** 5\
**Last updated:** [June 28, 2019, 4:28pm UTC](https://discourse.vtk.org/t/vtkstaticcelllocator-findclosestpoint/1091 "2019-06-28T16:28:53Z")

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Hi, the standard vtkCellLocator contains the method FindClosestPoint, but with a bigger dataset, it’s getting slow. I thought I could parallelize my call to Locator::FindClosestPoint(…) but this method use QueryNumber …

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## [painting vtkWindowToImageFilter output into QPixmap in Qt widget](https://discourse.vtk.org/t/painting-vtkwindowtoimagefilter-output-into-qpixmap-in-qt-widget/1226)

<div class="topic-metadata">

**Author:** [@sbucc](https://discourse.vtk.org/u/sbucc)\
**Replies:** 3\
**Last updated:** [June 28, 2019, 4:27pm UTC](https://discourse.vtk.org/t/painting-vtkwindowtoimagefilter-output-into-qpixmap-in-qt-widget/1226 "2019-06-28T16:27:58Z")

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I’m trying to use vtkWindowToImageFilter to paint a single view of an object into a widget in my Qt application. The closest I can get is this (still wrong): # generate the view renderWin = vtk.vtkRenderWindow()…

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## [Use of Tessellation Shader in VTK](https://discourse.vtk.org/t/use-of-tessellation-shader-in-vtk/1181)

<div class="topic-metadata">

**Author:** [@Tharun](https://discourse.vtk.org/u/Tharun)\
**Replies:** 3\
**Last updated:** [June 28, 2019, 3:38pm UTC](https://discourse.vtk.org/t/use-of-tessellation-shader-in-vtk/1181 "2019-06-28T15:38:36Z")

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I have a triangular mesh(polygons as cells in vtkPolyData). Each point has different scalar value. There is a lookup table for coloring based on scalars. On using Point Color data as scalars, triangles have graded colo…

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## [vtkResliceImageViewer](https://discourse.vtk.org/t/vtkresliceimageviewer/1233)

<div class="topic-metadata">

**Author:** [@Marco\_Festugato](https://discourse.vtk.org/u/Marco_Festugato)\
**Replies:** 0\
**Last updated:** [June 28, 2019, 8:36am UTC](https://discourse.vtk.org/t/vtkresliceimageviewer/1233 "2019-06-28T08:36:07Z")

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Hello, I want to perform MPR on my 3D volume and display the 3 planes (axial, coronal and sagittal) in one render window. Problem is that, if I want to change the cursor (and update the other 2 views) in the upper plane …

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## [Generating 3d body mesh from pointcloud](https://discourse.vtk.org/t/generating-3d-body-mesh-from-pointcloud/545)

<div class="topic-metadata">

**Author:** [@thully](https://discourse.vtk.org/u/thully)\
**Replies:** 8\
**Last updated:** [June 28, 2019, 7:50am UTC](https://discourse.vtk.org/t/generating-3d-body-mesh-from-pointcloud/545 "2019-06-28T07:50:39Z")

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I have several pointcloud files consisting of x, y, and z points associated with a human body. What I’d like to do is generate a 3d mesh of this body from the pointcloud. Is this possible, and if so what filters should I…

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## [2D vtk Renders in QT](https://discourse.vtk.org/t/2d-vtk-renders-in-qt/1231)

<div class="topic-metadata">

**Author:** [@ChristopherWaters](https://discourse.vtk.org/u/ChristopherWaters)\
**Replies:** 2\
**Last updated:** [June 28, 2019, 5:45am UTC](https://discourse.vtk.org/t/2d-vtk-renders-in-qt/1231 "2019-06-28T05:45:20Z")

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I am unable to do 2D vtk renders in QT without having override errors: “Generic Warning: In vtkContextDevice2D.cxx, line 31 Error: no override found for 'vtkContextDevice2D”. While trying to solve this I have been read…

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## [vtk rendering problem on embedded linux](https://discourse.vtk.org/t/vtk-rendering-problem-on-embedded-linux/1229)

<div class="topic-metadata">

**Author:** [@1112](https://discourse.vtk.org/u/1112)\
**Replies:** 0\
**Last updated:** [June 28, 2019, 2:25am UTC](https://discourse.vtk.org/t/vtk-rendering-problem-on-embedded-linux/1229 "2019-06-28T02:25:39Z")

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hello everyone I build vtk8.2.0 by nanopi m4 (OS is ‘Armbian Bionic desktop legacy kernel 4.4.y’). At first time vtk was successfully, but rendering is very slow and FPS is only about 5 I use ‘glmark2-es2’ to evaluate…

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## [vtkVolume can color mapping?](https://discourse.vtk.org/t/vtkvolume-can-color-mapping/1207)

<div class="topic-metadata">

**Author:** [@Script\_K](https://discourse.vtk.org/u/Script_K)\
**Replies:** 8\
**Last updated:** [June 27, 2019, 11:34pm UTC](https://discourse.vtk.org/t/vtkvolume-can-color-mapping/1207 "2019-06-27T23:34:07Z")

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now i making pI’m creating a program that overlays two objects and prints one object with color mapping based on the coordinate values. The overlay output was successful, but I could not find a way to do color mapping. …

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