# Development

**URL:** https://discourse.vtk.org/c/development/7.md?page=19

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

**Page:** 20

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## [Color Mask Overlay support in vtkResliceImageViewer??](https://discourse.vtk.org/t/color-mask-overlay-support-in-vtkresliceimageviewer/4471)

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**Author:** [@sherinnovation](https://discourse.vtk.org/u/sherinnovation)\
**Replies:** 2\
**Last updated:** [August 1, 2023, 2:46am UTC](https://discourse.vtk.org/t/color-mask-overlay-support-in-vtkresliceimageviewer/4471 "2023-08-01T02:46:04Z")

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I have an MRI volume data as well as a corresponding binary mask volume that defines certain sub regions of interest in the original MRI volume. Can I use my binary mask volume as a color overlay on top of vtkResliceImag…

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## [Does the VTKCommand InteractionEvent also gets triggered when we use the mouse wheel?](https://discourse.vtk.org/t/does-the-vtkcommand-interactionevent-also-gets-triggered-when-we-use-the-mouse-wheel/12055)

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**Author:** [@adityaDas](https://discourse.vtk.org/u/adityaDas)\
**Replies:** 1\
**Last updated:** [July 28, 2023, 7:20pm UTC](https://discourse.vtk.org/t/does-the-vtkcommand-interactionevent-also-gets-triggered-when-we-use-the-mouse-wheel/12055 "2023-07-28T19:20:54Z")

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I am using the callback function that is supposed to get triggered every time there is an interaction with the objects in the scene. For that, I am using the VTKCommand InteractionEvent. However, what I have noticed is t…

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## [How to use property UseImageActor of ResliceCursorRepresentation class](https://discourse.vtk.org/t/how-to-use-property-useimageactor-of-reslicecursorrepresentation-class/12048)

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**Author:** [@quantiehan](https://discourse.vtk.org/u/quantiehan)\
**Replies:** 0\
**Last updated:** [July 28, 2023, 1:12am UTC](https://discourse.vtk.org/t/how-to-use-property-useimageactor-of-reslicecursorrepresentation-class/12048 "2023-07-28T01:12:30Z")

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The default value of UseImageActor is zero. If set to 1, the image will not be displayed. Why I try it, The reason is that the same window width and window level result in a significant difference in grayscale display …

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## [how to get the individual polygon from the vtkpolydatareader (\*.vtk)](https://discourse.vtk.org/t/how-to-get-the-individual-polygon-from-the-vtkpolydatareader-vtk/12040)

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**Author:** [@senthilgis](https://discourse.vtk.org/u/senthilgis)\
**Replies:** 0\
**Last updated:** [July 27, 2023, 9:14am UTC](https://discourse.vtk.org/t/how-to-get-the-individual-polygon-from-the-vtkpolydatareader-vtk/12040 "2023-07-27T09:14:35Z")

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Hi, Can anyone help me to get the separate polygon from the set of polys array ? var reader = vtk.IO.Legacy.vtkPolyDataReader.newInstance(); const polydata = reader.getOutputData(); const polys = polydata.getPolys().…

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## [Visualize real-time data to VTK using images or images from RealSense SDK2 Cam D435 models (using MFC)](https://discourse.vtk.org/t/visualize-real-time-data-to-vtk-using-images-or-images-from-realsense-sdk2-cam-d435-models-using-mfc/12036)

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**Author:** [@Kim](https://discourse.vtk.org/u/Kim)\
**Replies:** 0\
**Last updated:** [July 27, 2023, 5:12am UTC](https://discourse.vtk.org/t/visualize-real-time-data-to-vtk-using-images-or-images-from-realsense-sdk2-cam-d435-models-using-mfc/12036 "2023-07-27T05:12:35Z")

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Hello, I am currently using RealSense Camera D435 I want to show the video image of Realsensers2sdk to VTK in real time, but I left it because I was wondering how to approach it and how to convert the image data from RS…

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## [Expanding a closed contour surface by some distance with the help of surface normals.](https://discourse.vtk.org/t/expanding-a-closed-contour-surface-by-some-distance-with-the-help-of-surface-normals/11724)

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**Author:** [@Sai\_Chaitanya\_Rodda](https://discourse.vtk.org/u/Sai_Chaitanya_Rodda)\
**Replies:** 4\
**Last updated:** [July 27, 2023, 3:28am UTC](https://discourse.vtk.org/t/expanding-a-closed-contour-surface-by-some-distance-with-the-help-of-surface-normals/11724 "2023-07-27T03:28:16Z")

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Hello Everyone, I have a closed contour polydata with points and normals (created from vtkPolyDataNormals). I tried to exoand the contour with the help of the normals by a certain distance (1 m). This I have done by cal…

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## [vtkPolyDataNormals appears to behave incorrectly](https://discourse.vtk.org/t/vtkpolydatanormals-appears-to-behave-incorrectly/11988)

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**Author:** [@whereismymoney](https://discourse.vtk.org/u/whereismymoney)\
**Replies:** 4\
**Last updated:** [July 22, 2023, 11:33pm UTC](https://discourse.vtk.org/t/vtkpolydatanormals-appears-to-behave-incorrectly/11988 "2023-07-22T23:33:55Z")

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The sample code I provide here allows you to easily compare SetComputePointNormals(true) and SetComputePointNormals(false), so we can compare the correct behavior with the incorrect behavior, shown in this image: Her…

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## [vtkDelaunay2D failed to triangulate some special concav polygons](https://discourse.vtk.org/t/vtkdelaunay2d-failed-to-triangulate-some-special-concav-polygons/9811)

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**Author:** [@Robinhwd](https://discourse.vtk.org/u/Robinhwd)\
**Replies:** 11\
**Last updated:** [November 22, 2022, 1:44am UTC](https://discourse.vtk.org/t/vtkdelaunay2d-failed-to-triangulate-some-special-concav-polygons/9811 "2022-11-22T01:44:04Z")

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Hi vtkers, I was trying to triangulate a mesh which includes two special concav polygons. The triangulation was perfect by using VTK 5.10 (vtkDelaunay2D), however when I update VTK to 9.2, it failed. Some triangles…

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## [The code throws SIGSEGV after upgrading to VTK 9.2.6](https://discourse.vtk.org/t/the-code-throws-sigsegv-after-upgrading-to-vtk-9-2-6/11955)

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**Author:** [@efourkal](https://discourse.vtk.org/u/efourkal)\
**Replies:** 3\
**Last updated:** [July 18, 2023, 12:46pm UTC](https://discourse.vtk.org/t/the-code-throws-sigsegv-after-upgrading-to-vtk-9-2-6/11955 "2023-07-18T12:46:28Z")

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I have upgraded VTK from version 9.1 to 9.2.6. The code compiles, but throws SIGSEGV signal. GDB debugging gives the following: Thread 2 received signal SIGSEGV, Segmentation fault. vtkPoints::InsertNextPoint (this=0x6…

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## [Help: Contour lines displayed discontinous](https://discourse.vtk.org/t/help-contour-lines-displayed-discontinous/11948)

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**Author:** [@hxf0223](https://discourse.vtk.org/u/hxf0223)\
**Replies:** 6\
**Last updated:** [July 17, 2023, 12:16pm UTC](https://discourse.vtk.org/t/help-contour-lines-displayed-discontinous/11948 "2023-07-17T12:16:05Z")

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I’m new on VTK, there’s a problem I do not know how to resolve: Select a contour to display using vtkContourFilter (The input data is a vtkUnstructuredGrid) filter-\>SetInputData(grid); filter-\>SetValue(0, 0.0); filter-\>S…

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## [How can I show just border of Actor](https://discourse.vtk.org/t/how-can-i-show-just-border-of-actor/11903)

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**Author:** [@A.M\_Shahpouri](https://discourse.vtk.org/u/A.M_Shahpouri)\
**Replies:** 6\
**Last updated:** [July 15, 2023, 8:28am UTC](https://discourse.vtk.org/t/how-can-i-show-just-border-of-actor/11903 "2023-07-15T08:28:26Z")

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Hi I have a filled Actor Now I want to view just Border of this actor how can I do this?

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## [vtkCaption2D border size](https://discourse.vtk.org/t/vtkcaption2d-border-size/11947)

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**Author:** [@DominionSoftware](https://discourse.vtk.org/u/DominionSoftware)\
**Replies:** 0\
**Last updated:** [July 14, 2023, 2:54pm UTC](https://discourse.vtk.org/t/vtkcaption2d-border-size/11947 "2023-07-14T14:54:39Z")

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I’m having trouble gettting the size of the border to match the text. It seems a bit like a catch 22 in that the size of the text is not known until render. So getting the bounds of a new caption before rendering is in…

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## [about vtk SMP](https://discourse.vtk.org/t/about-vtk-smp/11941)

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**Author:** [@marlon.ma](https://discourse.vtk.org/u/marlon.ma)\
**Replies:** 2\
**Last updated:** [July 14, 2023, 1:01am UTC](https://discourse.vtk.org/t/about-vtk-smp/11941 "2023-07-14T01:01:48Z")

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ImageMapToColors = vtkSmartPointer\<vtkImageMapToWindowLevelColors\>::New(); ImageMapToColors-\>SetWindow(Window); ImageMapToColors-\>SetLevel(level); ImageMapToColors-\>SetInputData(ImageData); ImageMapToColors-\>SetEnabl…

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## [Get Wrong World position When Rotate Image Data](https://discourse.vtk.org/t/get-wrong-world-position-when-rotate-image-data/11933)

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**Author:** [@m.h.shanazary](https://discourse.vtk.org/u/m.h.shanazary)\
**Replies:** 0\
**Last updated:** [July 12, 2023, 1:51pm UTC](https://discourse.vtk.org/t/get-wrong-world-position-when-rotate-image-data/11933 "2023-07-12T13:51:47Z")

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Hi I Get World Position With vtkWorldPointPicker Its Work When Have not Rotate image Data but When I Rotate VtkImageData its wrong working its my code Rotate And Method To Get Mouse position Method I get world position …

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## [Issue about cmake VTK for QVTKOpenGLNativeWidget](https://discourse.vtk.org/t/issue-about-cmake-vtk-for-qvtkopenglnativewidget/11909)

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**Author:** [@yen](https://discourse.vtk.org/u/yen)\
**Replies:** 1\
**Last updated:** [July 11, 2023, 9:56pm UTC](https://discourse.vtk.org/t/issue-about-cmake-vtk-for-qvtkopenglnativewidget/11909 "2023-07-11T21:56:53Z")

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Hello, I am currently using Qt6 and VTK-9.2. When I want to use QVTKOpenGLNativeWidget, I re-compile my vtk by cmake-gui. However, when I finished configuring VTK, my building and install procedure kept encountering erro…

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## [vtkQWidgetWidget Example usage (other than the unit tests)](https://discourse.vtk.org/t/vtkqwidgetwidget-example-usage-other-than-the-unit-tests/11893)

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**Author:** [@Michael\_Jackson](https://discourse.vtk.org/u/Michael_Jackson)\
**Replies:** 1\
**Last updated:** [July 7, 2023, 9:05am UTC](https://discourse.vtk.org/t/vtkqwidgetwidget-example-usage-other-than-the-unit-tests/11893 "2023-07-07T09:05:10Z")

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Is there a working example that uses the vtkQWidgetWidget with Qt6 (Hopefully). I tried to adapt the unit test bits into our application but nothing shows up that we can “see”. Was just adding a simple QButton. I’d like …

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## [ReadPixel slowly web gl](https://discourse.vtk.org/t/readpixel-slowly-web-gl/11877)

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**Author:** [@mazurkin.daniel](https://discourse.vtk.org/u/mazurkin.daniel)\
**Replies:** 0\
**Last updated:** [July 5, 2023, 8:30am UTC](https://discourse.vtk.org/t/readpixel-slowly-web-gl/11877 "2023-07-05T08:30:00Z")

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Hello, there is a problem when using ReadPixel for transferring 3D Slicer tools to the browser. This issue was discovered through graphics execution profiling. What are the possible solutions to this problem?

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## [Problem with Gouraud shading and bitmap texture](https://discourse.vtk.org/t/problem-with-gouraud-shading-and-bitmap-texture/11869)

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**Author:** [@Jon](https://discourse.vtk.org/u/Jon)\
**Replies:** 0\
**Last updated:** [July 3, 2023, 2:55pm UTC](https://discourse.vtk.org/t/problem-with-gouraud-shading-and-bitmap-texture/11869 "2023-07-03T14:55:36Z")

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Good day everyone, I’m having difficulty with applying Gouraud shading to a textured mesh in vtk.js. I created two meshes identically by adding points and cells from external data. Vertex normals were added to polyData…

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## [I may have discovered a bug about vtkAngeWidget](https://discourse.vtk.org/t/i-may-have-discovered-a-bug-about-vtkangewidget/11757)

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**Author:** [@marlon.ma](https://discourse.vtk.org/u/marlon.ma)\
**Replies:** 1\
**Last updated:** [July 3, 2023, 5:46am UTC](https://discourse.vtk.org/t/i-may-have-discovered-a-bug-about-vtkangewidget/11757 "2023-07-03T05:46:35Z")

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I have recently been developing the placement of multiple vtkAngleWidgets in the vtkRestricterImageViewer, but I have found that when placing multiple vtkAngleWidgets, there will be some situations where the haldles cann…

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## [Why is my CUBE not displayed in vtkRenderWindow ?](https://discourse.vtk.org/t/why-is-my-cube-not-displayed-in-vtkrenderwindow/11809)

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**Author:** [@zhuofalin](https://discourse.vtk.org/u/zhuofalin)\
**Replies:** 1\
**Last updated:** [June 28, 2023, 7:00pm UTC](https://discourse.vtk.org/t/why-is-my-cube-not-displayed-in-vtkrenderwindow/11809 "2023-06-28T19:00:34Z")

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When I ran the example code today, I found that the code ran successfully, but the window showing the result was not displayed. What is the reason? Environment: windows10, IDE: VS2022, and use cmake to program .sln …

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## [Visibility, camera and mesh](https://discourse.vtk.org/t/visibility-camera-and-mesh/11812)

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**Author:** [@Victor](https://discourse.vtk.org/u/Victor)\
**Replies:** 9\
**Last updated:** [June 28, 2023, 7:13am UTC](https://discourse.vtk.org/t/visibility-camera-and-mesh/11812 "2023-06-28T07:13:09Z")

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Hello everyone, I have a problem to be solved. There is a triangular mesh of STL format and 3 cameras in my scene. I need to get the index ID of all the mesh faces that is visible to each camera. Since there are close…

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## [Highlighting the edges of an actor](https://discourse.vtk.org/t/highlighting-the-edges-of-an-actor/1343)

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**Author:** [@at123](https://discourse.vtk.org/u/at123)\
**Replies:** 16\
**Last updated:** [June 28, 2023, 2:14am UTC](https://discourse.vtk.org/t/highlighting-the-edges-of-an-actor/1343 "2023-06-28T02:14:01Z")

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Hello, I am trying to highlight the edges of an actor when I select it with the cursor. Is there a method that has this functionality? I would greatly appreciate any help. Thanks.

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## [Render() was called after Start() when not offScreen, but not called when offScreen](https://discourse.vtk.org/t/render-was-called-after-start-when-not-offscreen-but-not-called-when-offscreen/11764)

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**Author:** [@gpu](https://discourse.vtk.org/u/gpu)\
**Replies:** 1\
**Last updated:** [June 25, 2023, 2:45am UTC](https://discourse.vtk.org/t/render-was-called-after-start-when-not-offscreen-but-not-called-when-offscreen/11764 "2023-06-25T02:45:37Z")

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after SetOffScreenRendering(1), Render() was not called after Start(). However, when SetOffScreenRendering(0), Render() was called after Start(). why? thanks

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## [We assembled a widget from 3D Slicer in the browser](https://discourse.vtk.org/t/we-assembled-a-widget-from-3d-slicer-in-the-browser/11756)

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**Author:** [@mazurkin.daniel](https://discourse.vtk.org/u/mazurkin.daniel)\
**Replies:** 16\
**Last updated:** [June 23, 2023, 2:07am UTC](https://discourse.vtk.org/t/we-assembled-a-widget-from-3d-slicer-in-the-browser/11756 "2023-06-23T02:07:32Z")

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We assembled a widget from 3D Slicer in the browser, and if you’re interested, we can share the instructions.

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## [porting a C++ example to Emscripten](https://discourse.vtk.org/t/porting-a-c-example-to-emscripten/4687)

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**Author:** [@SArbabi](https://discourse.vtk.org/u/SArbabi)\
**Replies:** 12\
**Last updated:** [June 23, 2023, 2:02am UTC](https://discourse.vtk.org/t/porting-a-c-example-to-emscripten/4687 "2023-06-23T02:02:19Z")

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Hi, upon running cmake -G Ninja for one of the C++ examples to the Emscripten folder, I get this error: CMake Warning at CMakeLists.txt:17 (find\_package): By not providing "FindVTK.cmake" in CMAKE\_MODULE\_PATH this pr…

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## [is it able to directly draw to the backbuffer(or offScreen framebuffer) of vtkOpenGLRenderWindow by CUDA](https://discourse.vtk.org/t/is-it-able-to-directly-draw-to-the-backbuffer-or-offscreen-framebuffer-of-vtkopenglrenderwindow-by-cuda/11763)

<div class="topic-metadata">

**Author:** [@gpu](https://discourse.vtk.org/u/gpu)\
**Replies:** 0\
**Last updated:** [June 19, 2023, 2:58pm UTC](https://discourse.vtk.org/t/is-it-able-to-directly-draw-to-the-backbuffer-or-offscreen-framebuffer-of-vtkopenglrenderwindow-by-cuda/11763 "2023-06-19T14:58:39Z")

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not OffScreen mode, is it to cudaGraphicsGLRegisterBuffer the backBuffer of vtkOpenGLRenderWindow? while OffScreen mode, is it to cudaGraphicsGLRegisterBuffer the framebuffer of vtkOpenGLRenderWindow? meanwhile using Cr…

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## [Access to intermediate points \`vtkContourRepresentation\`](https://discourse.vtk.org/t/access-to-intermediate-points-vtkcontourrepresentation/11755)

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**Author:** [@Jens\_Munk\_Hansen](https://discourse.vtk.org/u/Jens_Munk_Hansen)\
**Replies:** 1\
**Last updated:** [June 18, 2023, 7:37pm UTC](https://discourse.vtk.org/t/access-to-intermediate-points-vtkcontourrepresentation/11755 "2023-06-18T19:37:30Z")

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I working with the family of vtkContourWidget specifically to define trajectories on surfaces of organs. I decided to inherit the representation to expose the intermediate points and create an observer which defines orie…

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## [How to use GPU rendering when using qquickvtkitem](https://discourse.vtk.org/t/how-to-use-gpu-rendering-when-using-qquickvtkitem/11752)

<div class="topic-metadata">

**Author:** [@notThisMoment](https://discourse.vtk.org/u/notThisMoment)\
**Replies:** 0\
**Last updated:** [June 18, 2023, 9:17am UTC](https://discourse.vtk.org/t/how-to-use-gpu-rendering-when-using-qquickvtkitem/11752 "2023-06-18T09:17:10Z")

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Always use the CPU instead of the GPU when rendering, even when vtkopenglrenderwindow is used

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## [how to create vtk mesh with texture](https://discourse.vtk.org/t/how-to-create-vtk-mesh-with-texture/11749)

<div class="topic-metadata">

**Author:** [@ZUNTING\_HU](https://discourse.vtk.org/u/ZUNTING_HU)\
**Replies:** 0\
**Last updated:** [June 17, 2023, 10:21am UTC](https://discourse.vtk.org/t/how-to-create-vtk-mesh-with-texture/11749 "2023-06-17T10:21:01Z")

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I have one mesh in memory , one image in memory and every vertex texture coordinate in the image. how to create vtk mesh polydate with this source?

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## [vtkLineSource has setPoint1(Vector3) but only setPoint2(x,y,z)?](https://discourse.vtk.org/t/vtklinesource-has-setpoint1-vector3-but-only-setpoint2-x-y-z/11704)

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**Author:** [@JohnSkinner](https://discourse.vtk.org/u/JohnSkinner)\
**Replies:** 0\
**Last updated:** [June 13, 2023, 5:32pm UTC](https://discourse.vtk.org/t/vtklinesource-has-setpoint1-vector3-but-only-setpoint2-x-y-z/11704 "2023-06-13T17:32:10Z")

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probably should have a setPoint2(Vector3) also. noted for vtk.js 28.2.1

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