# Latest

**URL:** https://discourse.vtk.org/latest.md?page=240

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

**Page:** 241

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## [QVTKWidget render window is outside main Qt app window](https://discourse.vtk.org/t/qvtkwidget-render-window-is-outside-main-qt-app-window/1539)

<div class="topic-metadata">

**Author:** [@Edoardo\_Pasca](https://discourse.vtk.org/u/Edoardo_Pasca)\
**Replies:** 10\
**Last updated:** [August 14, 2019, 12:31pm UTC](https://discourse.vtk.org/t/qvtkwidget-render-window-is-outside-main-qt-app-window/1539 "2019-08-14T12:31:53Z")

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Hi all, I put together a VTK viewer in Python. I also extended QVTKWidget to host the viewer in a Qt app. It all looks and works fine with Qt 5.9.7 and VTK 8.1.2 on windows (in a conda environment). If I set up the “sa…

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## [Problems and questions using vtkSmartVolumeMapper for large volume streaming and rendering](https://discourse.vtk.org/t/problems-and-questions-using-vtksmartvolumemapper-for-large-volume-streaming-and-rendering/656)

<div class="topic-metadata">

**Author:** [@csparker247](https://discourse.vtk.org/u/csparker247)\
**Replies:** 18\
**Last updated:** [August 14, 2019, 9:29am UTC](https://discourse.vtk.org/t/problems-and-questions-using-vtksmartvolumemapper-for-large-volume-streaming-and-rendering/656 "2019-08-14T09:29:02Z")

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I need to volume render datasets with a wide range of volume sizes: 5-120GBs is common and 120GB+ are rare but still happen. This will mostly be for non-interactive scenarios (predefined animations or stills), so I can a…

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## [What is the purpose of this line?](https://discourse.vtk.org/t/what-is-the-purpose-of-this-line/1575)

<div class="topic-metadata">

**Author:** [@at123](https://discourse.vtk.org/u/at123)\
**Replies:** 5\
**Last updated:** [August 14, 2019, 3:37am UTC](https://discourse.vtk.org/t/what-is-the-purpose-of-this-line/1575 "2019-08-14T03:37:45Z")

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Hello, I am trying to understand vtkVoxelContourToSurface. I am looking at this example, https://www.paraview.org/Wiki/VTK/Examples/Cxx/PolyData/ContoursToSurface What is the purpose of these three lines? pt\[0\] = stat…

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## [vtkViewport's purpose](https://discourse.vtk.org/t/vtkviewports-purpose/1576)

<div class="topic-metadata">

**Author:** [@at123](https://discourse.vtk.org/u/at123)\
**Replies:** 1\
**Last updated:** [August 13, 2019, 9:24pm UTC](https://discourse.vtk.org/t/vtkviewports-purpose/1576 "2019-08-13T21:24:55Z")

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Hello, what is the purpose of using SetViewport on a vtkRenderer object. What does it do? Thank you.

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## [Import images progressive](https://discourse.vtk.org/t/import-images-progressive/1571)

<div class="topic-metadata">

**Author:** [@yonvaida](https://discourse.vtk.org/u/yonvaida)\
**Replies:** 0\
**Last updated:** [August 13, 2019, 9:16am UTC](https://discourse.vtk.org/t/import-images-progressive/1571 "2019-08-13T09:16:05Z")

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Hello, I create a software that reads dicom images. Images is received from server and i wanted to load them progressive, when image comes i want to append it to vtkImageData. Can someone help me ? Thanks

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## [how to get the image postion](https://discourse.vtk.org/t/how-to-get-the-image-postion/1535)

<div class="topic-metadata">

**Author:** [@pingdan](https://discourse.vtk.org/u/pingdan)\
**Replies:** 2\
**Last updated:** [August 13, 2019, 8:12am UTC](https://discourse.vtk.org/t/how-to-get-the-image-postion/1535 "2019-08-13T08:12:39Z")

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as the graph.I show a picture in a renderer, and I know the renderer size and the picture size.when I press left button down, I can get a point position in the renderer. I want to judge if the point locate on picture. …

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## [intersection two stl](https://discourse.vtk.org/t/intersection-two-stl/1550)

<div class="topic-metadata">

**Author:** [@vahid\_rastgoo](https://discourse.vtk.org/u/vahid_rastgoo)\
**Replies:** 7\
**Last updated:** [August 13, 2019, 1:46am UTC](https://discourse.vtk.org/t/intersection-two-stl/1550 "2019-08-13T01:46:03Z")

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Hello beloveds How to find out if two stl files collided or collapsed in vtk with python But I don’t want to use the vtkcollisiondetectionfilter class, is there any other way?

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## [glFog or depth cueing](https://discourse.vtk.org/t/glfog-or-depth-cueing/1566)

<div class="topic-metadata">

**Author:** [@fcollman](https://discourse.vtk.org/u/fcollman)\
**Replies:** 1\
**Last updated:** [August 13, 2019, 1:15am UTC](https://discourse.vtk.org/t/glfog-or-depth-cueing/1566 "2019-08-13T01:15:31Z")

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I couldn’t figure out how in vtk to get a rendering effect like ‘fog’ where things fade as they get farther away from the camera. This is sometimes called ‘depth cueing’ such as in this product… http://docs.pixologic.c…

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## [Python VTK for visualization in a jupyter notebook running on docker](https://discourse.vtk.org/t/python-vtk-for-visualization-in-a-jupyter-notebook-running-on-docker/622)

<div class="topic-metadata">

**Author:** [@harp](https://discourse.vtk.org/u/harp)\
**Replies:** 8\
**Last updated:** [August 12, 2019, 10:45pm UTC](https://discourse.vtk.org/t/python-vtk-for-visualization-in-a-jupyter-notebook-running-on-docker/622 "2019-08-12T22:45:04Z")

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Hi - I’d like to use python vtk to visualize objects in a jupyter notebook. I am able to run the notebook locally on my machine and it works. However, I am unable to run it when the jupyter notebook is running in docker …

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## [is it possible to use vtkDistanceToCamera to keep an actor size fixed without using vtkGlyph3D](https://discourse.vtk.org/t/is-it-possible-to-use-vtkdistancetocamera-to-keep-an-actor-size-fixed-without-using-vtkglyph3d/1559)

<div class="topic-metadata">

**Author:** [@embeddedmz](https://discourse.vtk.org/u/embeddedmz)\
**Replies:** 1\
**Last updated:** [August 12, 2019, 2:45pm UTC](https://discourse.vtk.org/t/is-it-possible-to-use-vtkdistancetocamera-to-keep-an-actor-size-fixed-without-using-vtkglyph3d/1559 "2019-08-12T14:45:59Z")

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Hi, First of all, there’s this example : https://vtk.org/Wiki/VTK/Examples/Cxx/Visualization/DistanceToCamera that shows how to keep 2 arrows size fixed, whatever the camera zoom level using vtkDistanceToCamera and vtkG…

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## [OSPRay features supported in vtkOSPRayRenderNode](https://discourse.vtk.org/t/ospray-features-supported-in-vtkosprayrendernode/1489)

<div class="topic-metadata">

**Author:** [@Sean\_Curtis](https://discourse.vtk.org/u/Sean_Curtis)\
**Replies:** 7\
**Last updated:** [August 12, 2019, 1:41pm UTC](https://discourse.vtk.org/t/ospray-features-supported-in-vtkosprayrendernode/1489 "2019-08-12T13:41:16Z")

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I’m having difficulty reasoning about documented OSPRay functionality and how to access it via VTK. Is there some definitive document somewhere that articulates that mapping that I’ve missed? Or is there some philosophic…

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## [Segfault with QVTKWidget](https://discourse.vtk.org/t/segfault-with-qvtkwidget/1545)

<div class="topic-metadata">

**Author:** [@Gib\_Bogle](https://discourse.vtk.org/u/Gib_Bogle)\
**Replies:** 2\
**Last updated:** [August 11, 2019, 11:40pm UTC](https://discourse.vtk.org/t/segfault-with-qvtkwidget/1545 "2019-08-11T23:40:16Z")

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The following code works on Windows, but the last line causes a crash on Linux (Ubuntu 16.04): (page\_VTK points to a QMdiArea widget that has been created on a form) qvtkWidget = new QVTKWidget(page\_VTK,QFlag(0)); QVB…

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## [collision of two objects](https://discourse.vtk.org/t/collision-of-two-objects/1519)

<div class="topic-metadata">

**Author:** [@Vahid](https://discourse.vtk.org/u/Vahid)\
**Replies:** 4\
**Last updated:** [August 11, 2019, 9:03pm UTC](https://discourse.vtk.org/t/collision-of-two-objects/1519 "2019-08-11T21:03:26Z")

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Dear All, I imported two objects and I would like to detect the collision of theses objects. After the contact, I want to stop the moving object. Could you please give me some advise on this question ? Thanks

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## [Signed vs. unsigned pixel data in DICOMAppHelper](https://discourse.vtk.org/t/signed-vs-unsigned-pixel-data-in-dicomapphelper/955)

<div class="topic-metadata">

**Author:** [@jfollweiler](https://discourse.vtk.org/u/jfollweiler)\
**Replies:** 6\
**Last updated:** [August 11, 2019, 8:39pm UTC](https://discourse.vtk.org/t/signed-vs-unsigned-pixel-data-in-dicomapphelper/955 "2019-08-11T20:39:00Z")

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I’m attempting to use the vtkDICOMImageReader class to read in some DICOM files. The pixel data in the DICOM file headers is written as signed shorts and is to be rescaled as floats. In the DICOMAppHelper class with th…

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## [Passing data](https://discourse.vtk.org/t/passing-data/1497)

<div class="topic-metadata">

**Author:** [@Richard\_Thompson](https://discourse.vtk.org/u/Richard_Thompson)\
**Replies:** 1\
**Last updated:** [August 11, 2019, 4:20am UTC](https://discourse.vtk.org/t/passing-data/1497 "2019-08-11T04:20:57Z")

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Hi, I have a 2 vtkDelaunay3D objects that I want to pass into vtkBooleanOPerationPolyDataFilter. What is the general syntax to accomplish this? Thanks.

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## [Empty position in Rectlinear \_grid dataset](https://discourse.vtk.org/t/empty-position-in-rectlinear-grid-dataset/1512)

<div class="topic-metadata">

**Author:** [@Jiaxiang\_Wang](https://discourse.vtk.org/u/Jiaxiang_Wang)\
**Replies:** 1\
**Last updated:** [August 11, 2019, 4:16am UTC](https://discourse.vtk.org/t/empty-position-in-rectlinear-grid-dataset/1512 "2019-08-11T04:16:38Z")

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Hi, For a rectlinear grid data set vtk file, it give the range of x,y,z coordinate. Then for each position, it will give a voxel (a number). Is there a way to declare that position doesn’t contain any voxel. For exampl…

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## [vtkMath, vtkPointLocator, vtkDistancePolyDataFilter issue](https://discourse.vtk.org/t/vtkmath-vtkpointlocator-vtkdistancepolydatafilter-issue/1487)

<div class="topic-metadata">

**Author:** [@at123](https://discourse.vtk.org/u/at123)\
**Replies:** 1\
**Last updated:** [August 11, 2019, 4:09am UTC](https://discourse.vtk.org/t/vtkmath-vtkpointlocator-vtkdistancepolydatafilter-issue/1487 "2019-08-11T04:09:36Z")

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Hello, I recieve these errors when I try to pass a vtkAppendPolyData to a vtkBooleanOperationPolyDataFilter. What do these errors mean? Any help would be appreciated. Thanks! Generic Warning: In /work/standalone-x64-bui…

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## [Segmentation Fault](https://discourse.vtk.org/t/segmentation-fault/1540)

<div class="topic-metadata">

**Author:** [@at123](https://discourse.vtk.org/u/at123)\
**Replies:** 2\
**Last updated:** [August 11, 2019, 4:02am UTC](https://discourse.vtk.org/t/segmentation-fault/1540 "2019-08-11T04:02:26Z")

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Hello, I get a segmentation fault (core dumped) error whenever I run my program. This happens when I draw non circular contours. Here is the code: def generateVolume(self): if len(self.reslicers\[self.contourOrient…

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## [How can I use a vtk interactor with an external event loop?](https://discourse.vtk.org/t/how-can-i-use-a-vtk-interactor-with-an-external-event-loop/335)

<div class="topic-metadata">

**Author:** [@langer](https://discourse.vtk.org/u/langer)\
**Replies:** 1\
**Last updated:** [August 9, 2019, 11:32am UTC](https://discourse.vtk.org/t/how-can-i-use-a-vtk-interactor-with-an-external-event-loop/335 "2019-08-09T11:32:48Z")

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I have a program that has a GUI written in gtk+2 and uses vtk for 3D graphics. Currently we handle all mouse and keyboard events in gtk+2, and don’t use a vtkRenderWindowInteractor at all. We call vtk methods in respo…

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## [Redefine Cells of simplex mesh](https://discourse.vtk.org/t/redefine-cells-of-simplex-mesh/1514)

<div class="topic-metadata">

**Author:** [@srbn.ghosh99](https://discourse.vtk.org/u/srbn.ghosh99)\
**Replies:** 1\
**Last updated:** [August 9, 2019, 11:28am UTC](https://discourse.vtk.org/t/redefine-cells-of-simplex-mesh/1514 "2019-08-09T11:28:22Z")

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Hi, In my simplex mesh, I want to Redefine some cells with different points and save them. Lets say , one cell has 6 points,(1,2,3,4,5,6). I want to eliminate one point from the cell and redefine with (1,2,3,4,5). I am…

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## [find the actor that another actor is intersecting with](https://discourse.vtk.org/t/find-the-actor-that-another-actor-is-intersecting-with/1379)

<div class="topic-metadata">

**Author:** [@svabhishek29](https://discourse.vtk.org/u/svabhishek29)\
**Replies:** 9\
**Last updated:** [August 9, 2019, 11:23am UTC](https://discourse.vtk.org/t/find-the-actor-that-another-actor-is-intersecting-with/1379 "2019-08-09T11:23:35Z")

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hi, i have a situation in which i have a sphere in a field of multiple randomly placed cubes, the sphere is controlled by keyboard and when the sphere intersects a cube or collides with a cube i want to change the color …

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## [Linking VTK static libraries](https://discourse.vtk.org/t/linking-vtk-static-libraries/1534)

<div class="topic-metadata">

**Author:** [@Gib\_Bogle](https://discourse.vtk.org/u/Gib_Bogle)\
**Replies:** 1\
**Last updated:** [August 9, 2019, 1:08am UTC](https://discourse.vtk.org/t/linking-vtk-static-libraries/1534 "2019-08-09T01:08:21Z")

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I am trying to port a program that uses VTK in a Qt GUI from Windows to Linux. To keep this as straightforward as possible I’m sticking with the Qt and VTK versions that I’ve been using: Qt-4.8.6 and VTK-5.10. The VTK …

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## [Images exported from OSPRay renders have channel values that max out at 254](https://discourse.vtk.org/t/images-exported-from-ospray-renders-have-channel-values-that-max-out-at-254/1531)

<div class="topic-metadata">

**Author:** [@Sean\_Curtis](https://discourse.vtk.org/u/Sean_Curtis)\
**Replies:** 0\
**Last updated:** [August 8, 2019, 9:33pm UTC](https://discourse.vtk.org/t/images-exported-from-ospray-renders-have-channel-values-that-max-out-at-254/1531 "2019-08-08T21:33:19Z")

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I’ve encountered two instances that suggest there’s some funny truncating taking place somewhere in either OSPRay or the OSPRay/VTK interface. Essentially, it comes down to the fact that colors are not coming back quite …

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## [New VTK Examples Project YouTube channel](https://discourse.vtk.org/t/new-vtk-examples-project-youtube-channel/1530)

<div class="topic-metadata">

**Author:** [@lorensen](https://discourse.vtk.org/u/lorensen)\
**Replies:** 0\
**Last updated:** [August 8, 2019, 7:57pm UTC](https://discourse.vtk.org/t/new-vtk-examples-project-youtube-channel/1530 "2019-08-08T19:57:04Z")

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Folks, We have created a new youtube channel for the VTK Examples Project here. The channel will provide video demonstrations of some examples. This new channel is a work in progress as we add new videos and documenta…

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## [Rendering issue with vtkImageViewer2 and Qt (works with vtkImageViewer)](https://discourse.vtk.org/t/rendering-issue-with-vtkimageviewer2-and-qt-works-with-vtkimageviewer/1529)

<div class="topic-metadata">

**Author:** [@NewProggie](https://discourse.vtk.org/u/NewProggie)\
**Replies:** 0\
**Last updated:** [August 8, 2019, 7:28pm UTC](https://discourse.vtk.org/t/rendering-issue-with-vtkimageviewer2-and-qt-works-with-vtkimageviewer/1529 "2019-08-08T19:28:51Z")

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Hello my fellow VTK users, I want to embed an instance of vtkImageViewer2 into my Qt5 application to visualize a series of DICOM images. I’m currently experiencing some rendering issues because the widget doesn’t displa…

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## [Documentation - Add a path to where the class is in the VTK directory.](https://discourse.vtk.org/t/documentation-add-a-path-to-where-the-class-is-in-the-vtk-directory/1389)

<div class="topic-metadata">

**Author:** [@amaclean](https://discourse.vtk.org/u/amaclean)\
**Replies:** 2\
**Last updated:** [August 8, 2019, 10:41am UTC](https://discourse.vtk.org/t/documentation-add-a-path-to-where-the-class-is-in-the-vtk-directory/1389 "2019-08-08T10:41:38Z")

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When looking at the classes in VTK Class List It would be nice to add in \*\* Detailed Description\*\* an indication as to where the class is in the VTK source. For example, in the case of /vtkSubdivideTetra, in \*\* Detaile…

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## [wglMakeCurrent failed in MakeCurrent()](https://discourse.vtk.org/t/wglmakecurrent-failed-in-makecurrent/1516)

<div class="topic-metadata">

**Author:** [@Wenye\_He](https://discourse.vtk.org/u/Wenye_He)\
**Replies:** 0\
**Last updated:** [August 8, 2019, 2:48am UTC](https://discourse.vtk.org/t/wglmakecurrent-failed-in-makecurrent/1516 "2019-08-08T02:48:00Z")

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I got an error, vtkWin32OpenGLRenderWindow (0000024A62E4C270): wglMakeCurrent failed in MakeCurrent(), error: The handle is invalid. What is this error and how to fix it? I create one mainwindow to display 3D model an…

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## [vtkSmithPlot vtkChart](https://discourse.vtk.org/t/vtksmithplot-vtkchart/1510)

<div class="topic-metadata">

**Author:** [@jal](https://discourse.vtk.org/u/jal)\
**Replies:** 0\
**Last updated:** [August 7, 2019, 7:52pm UTC](https://discourse.vtk.org/t/vtksmithplot-vtkchart/1510 "2019-08-07T19:52:06Z")

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Is anyone aware of an implementation of smith chart for vtkPlot/vtkChart? Didn’t want to go off on my own if something exists.

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## [Actor is oddly coloured](https://discourse.vtk.org/t/actor-is-oddly-coloured/1504)

<div class="topic-metadata">

**Author:** [@at123](https://discourse.vtk.org/u/at123)\
**Replies:** 6\
**Last updated:** [August 7, 2019, 6:43pm UTC](https://discourse.vtk.org/t/actor-is-oddly-coloured/1504 "2019-08-07T18:43:15Z")

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Hi, I declared a vtkActor and set it to one colour. I pass a vtkBooleanOperationPolyDataFilter to the vtkPolyDataMapper and then to the vtkActor. When the vtkActor is rendered, it is not the colour I specified. Instead,…

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## [What does this error mean?](https://discourse.vtk.org/t/what-does-this-error-mean/1509)

<div class="topic-metadata">

**Author:** [@at123](https://discourse.vtk.org/u/at123)\
**Replies:** 1\
**Last updated:** [August 7, 2019, 6:34pm UTC](https://discourse.vtk.org/t/what-does-this-error-mean/1509 "2019-08-07T18:34:21Z")

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HI, I pass a vtkBooleanOperationPolyDataFilter to vtkDelaunay3D. I create a mapper and actor to display it. The actor renders successfully, but I get this error: vtkDelaunay3D (0x3280c00): 1 degenerate triangles encoun…

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