# Latest

**URL:** https://discourse.vtk.org/latest.md?page=251

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

**Page:** 252

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## [overlapping 2 volumes in a render window](https://discourse.vtk.org/t/overlapping-2-volumes-in-a-render-window/775)

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**Author:** [@Marco\_Festugato](https://discourse.vtk.org/u/Marco_Festugato)\
**Replies:** 2\
**Last updated:** [April 23, 2019, 12:30pm UTC](https://discourse.vtk.org/t/overlapping-2-volumes-in-a-render-window/775 "2019-04-23T12:30:21Z")

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Hello, I have 199 CT slices of the liver (volume 1) from which I have segmented the liver vessels (volume 2: 199 slices containing only the vessels in binary images). Now I want to overlap these 2 volumes: I want to see…

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## [Is zfp used in VTK?](https://discourse.vtk.org/t/is-zfp-used-in-vtk/786)

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**Author:** [@opoplawski](https://discourse.vtk.org/u/opoplawski)\
**Replies:** 2\
**Last updated:** [April 22, 2019, 9:23pm UTC](https://discourse.vtk.org/t/is-zfp-used-in-vtk/786 "2019-04-22T21:23:21Z")

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There is ThirdParty/zfp in the VTK source - but I can’t find any evidence that it is in use. Is there some planned future use or should it be removed? https://gitlab.kitware.com/vtk/vtk/issues/17540

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## [VTK install directory control reduced in new build system](https://discourse.vtk.org/t/vtk-install-directory-control-reduced-in-new-build-system/811)

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**Author:** [@cryos](https://discourse.vtk.org/u/cryos)\
**Replies:** 3\
**Last updated:** [April 22, 2019, 4:23pm UTC](https://discourse.vtk.org/t/vtk-install-directory-control-reduced-in-new-build-system/811 "2019-04-22T16:23:52Z")

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We have been using VTK\_INSTALL\_LIBRARY\_DIR, VTK\_INSTALL\_ARCHIVE\_DIR etc to control where VTK (and ParaView) install their files. We did this to simplify packaging by removing version information from install directories,…

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## [Getting color codes of the points](https://discourse.vtk.org/t/getting-color-codes-of-the-points/809)

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**Author:** [@sariug](https://discourse.vtk.org/u/sariug)\
**Replies:** 0\
**Last updated:** [April 22, 2019, 10:52am UTC](https://discourse.vtk.org/t/getting-color-codes-of-the-points/809 "2019-04-22T10:52:09Z")

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Hello, I used streamtracer and happily got my streamline(points). I color them with velocity magnitudes. I am using an external viewer, therefore (in order not to calculate all the look up table data, velocities and mor…

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## [how to apply MIP on 2D DICOM](https://discourse.vtk.org/t/how-to-apply-mip-on-2d-dicom/725)

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**Author:** [@Aravind](https://discourse.vtk.org/u/Aravind)\
**Replies:** 1\
**Last updated:** [April 22, 2019, 7:34am UTC](https://discourse.vtk.org/t/how-to-apply-mip-on-2d-dicom/725 "2019-04-22T07:34:26Z")

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Hello - I am trying to do a MIP on the DICOM images. Not sure what I am doing wrong any help would be appreciated. Here is my code. I am unable to set up the pipeline I believe to scroll through the stack with the MIP. I…

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## [How to sample implicit function in different bounds](https://discourse.vtk.org/t/how-to-sample-implicit-function-in-different-bounds/808)

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**Author:** [@Frank](https://discourse.vtk.org/u/Frank)\
**Replies:** 0\
**Last updated:** [April 22, 2019, 6:42am UTC](https://discourse.vtk.org/t/how-to-sample-implicit-function-in-different-bounds/808 "2019-04-22T06:42:39Z")

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I get a vtkImplicitFunction object and want to sample it over a structured point set. I know the approximate shape of the implicit. So I want to sample vtkImplicitFunction in different bounds(they could be overlap) and f…

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## [Problems with vtkRenderWindowInteractor on macOS using Cocoa](https://discourse.vtk.org/t/problems-with-vtkrenderwindowinteractor-on-macos-using-cocoa/805)

<div class="topic-metadata">

**Author:** [@NoeMurr](https://discourse.vtk.org/u/NoeMurr)\
**Replies:** 2\
**Last updated:** [April 22, 2019, 2:21am UTC](https://discourse.vtk.org/t/problems-with-vtkrenderwindowinteractor-on-macos-using-cocoa/805 "2019-04-22T02:21:29Z")

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Hi all, I’m learning VTK reading the book VTKTextBook. I’ve tried to execute the Cone example at link: https://lorensen.github.io/VTKExamples/site/Cxx/GeometricObjects/Cone/ When I run it I’ve got a strange behavior …

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## [Four dipsplay Window](https://discourse.vtk.org/t/four-dipsplay-window/414)

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**Author:** [@dp1991](https://discourse.vtk.org/u/dp1991)\
**Replies:** 11\
**Last updated:** [April 22, 2019, 12:30am UTC](https://discourse.vtk.org/t/four-dipsplay-window/414 "2019-04-22T00:30:55Z")

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Hi i need to display my image into 4 window 1 axial 2- sagittal 3- coronal 4- 3D view like 3dslicer default how to do it ??

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## [displaying 3D volume in RED](https://discourse.vtk.org/t/displaying-3d-volume-in-red/804)

<div class="topic-metadata">

**Author:** [@Marco\_Festugato](https://discourse.vtk.org/u/Marco_Festugato)\
**Replies:** 2\
**Last updated:** [April 21, 2019, 3:46pm UTC](https://discourse.vtk.org/t/displaying-3d-volume-in-red/804 "2019-04-21T15:46:07Z")

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Hi, I want to display my 3D volume (range from 0 to 255) in uniform red. I’ve thought of this code: colorTransferFunction-\> AddRGBPoint (0.0 0.0 0.0 0.0); // i don't know if with …

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## [Contour isosurfaces for positive and negative values: orientation](https://discourse.vtk.org/t/contour-isosurfaces-for-positive-and-negative-values-orientation/800)

<div class="topic-metadata">

**Author:** [@Jellby](https://discourse.vtk.org/u/Jellby)\
**Replies:** 1\
**Last updated:** [April 20, 2019, 12:27pm UTC](https://discourse.vtk.org/t/contour-isosurfaces-for-positive-and-negative-values-orientation/800 "2019-04-20T12:27:25Z")

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I have some scalar field for which I want to represent contours for +v and -v simultaneously, with different colors, with the caveat that the contours for -v should be “reversed”, i.e., they enclose the volume for which …

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## [ResliceImageViewer for MPR](https://discourse.vtk.org/t/resliceimageviewer-for-mpr/799)

<div class="topic-metadata">

**Author:** [@Marco\_Festugato](https://discourse.vtk.org/u/Marco_Festugato)\
**Replies:** 0\
**Last updated:** [April 20, 2019, 8:11am UTC](https://discourse.vtk.org/t/resliceimageviewer-for-mpr/799 "2019-04-20T08:11:32Z")

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Hi all, I’m trying to figure it out how this class works. I have a 3D volume of which i want to perform MPR (like in the image below) I think I have to use the vtkResliceImageViewer but I dont understand how it works…

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## [Simulating stereo vision using VTK](https://discourse.vtk.org/t/simulating-stereo-vision-using-vtk/780)

<div class="topic-metadata">

**Author:** [@abaldur](https://discourse.vtk.org/u/abaldur)\
**Replies:** 5\
**Last updated:** [April 19, 2019, 10:57pm UTC](https://discourse.vtk.org/t/simulating-stereo-vision-using-vtk/780 "2019-04-19T22:57:19Z")

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Hi Suppose I want to use VTK to simulate a stereo vision system composed of a line laser and a camera. The laser is capable of projecting a uniform line beam onto some 3D geometry, which I have in the form of an STL f…

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## [vtkloguru link errors building Mac app that doesn't use CMake](https://discourse.vtk.org/t/vtkloguru-link-errors-building-mac-app-that-doesnt-use-cmake/795)

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**Author:** [@seanm](https://discourse.vtk.org/u/seanm)\
**Replies:** 2\
**Last updated:** [April 19, 2019, 8:13pm UTC](https://discourse.vtk.org/t/vtkloguru-link-errors-building-mac-app-that-doesnt-use-cmake/795 "2019-04-19T20:13:05Z")

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Hi all, For the first time in a few months, I’m trying to build my Mac app against vtk master. I’m getting link errors like: “vtkloguru::vstrprintf(char const\*, \_\_va\_list\_tag\*)”, referenced from: vtkLogger::LogScopeR…

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## [vtkImageResliceMapper and BorderOff() / BorderOn()](https://discourse.vtk.org/t/vtkimagereslicemapper-and-borderoff-borderon/794)

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**Author:** [@jonklingensmith](https://discourse.vtk.org/u/jonklingensmith)\
**Replies:** 0\
**Last updated:** [April 19, 2019, 5:25pm UTC](https://discourse.vtk.org/t/vtkimagereslicemapper-and-borderoff-borderon/794 "2019-04-19T17:25:05Z")

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I am trying to get a thin, colored border line - color coded to indicate axial, sagittal, and coronal - on the edge of 3 typical orthogonal cut planes through an image volume. It looks like I can possibly use vtkCutter()…

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## [How to get a reasonably good triangulated surface from a level-set volumetric field](https://discourse.vtk.org/t/how-to-get-a-reasonably-good-triangulated-surface-from-a-level-set-volumetric-field/765)

<div class="topic-metadata">

**Author:** [@rdbisme](https://discourse.vtk.org/u/rdbisme)\
**Replies:** 2\
**Last updated:** [April 19, 2019, 11:59am UTC](https://discourse.vtk.org/t/how-to-get-a-reasonably-good-triangulated-surface-from-a-level-set-volumetric-field/765 "2019-04-19T11:59:28Z")

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Hello, I’m exploring some algorithms to compute curvatures on surfaces and I’m using VTK under the hoods to manage the triangulation of a level-set surface (and data structures). The problem I’m encountering is a relati…

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## [Should we replace SafeDownCast with dynamic\_cast](https://discourse.vtk.org/t/should-we-replace-safedowncast-with-dynamic-cast/669)

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**Author:** [@lorensen](https://discourse.vtk.org/u/lorensen)\
**Replies:** 9\
**Last updated:** [April 19, 2019, 1:44am UTC](https://discourse.vtk.org/t/should-we-replace-safedowncast-with-dynamic-cast/669 "2019-04-19T01:44:59Z")

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Folks, SafeDownCast was added to vtk way back when dynamic\_cast was not available everywhere. Should we replace SafeDownCast in vtk with dynamic\_cast? It is more natural for modern C++ and is well-documented. It may …

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## [VTKExamples Links to vtk.js](https://discourse.vtk.org/t/vtkexamples-links-to-vtk-js/783)

<div class="topic-metadata">

**Author:** [@lorensen](https://discourse.vtk.org/u/lorensen)\
**Replies:** 0\
**Last updated:** [April 18, 2019, 10:22pm UTC](https://discourse.vtk.org/t/vtkexamples-links-to-vtk-js/783 "2019-04-18T22:22:28Z")

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We added a link to vtk.js on the VTKExamples Project. See: VTKExamples on ResearchGate and click on Project Log to see the announcement. Also, feel free to browse VTKExamples Bill

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## [VTK Hackathon](https://discourse.vtk.org/t/vtk-hackathon/662)

<div class="topic-metadata">

**Author:** [@will.schroeder](https://discourse.vtk.org/u/will.schroeder)\
**Replies:** 15\
**Last updated:** [April 18, 2019, 5:49pm UTC](https://discourse.vtk.org/t/vtk-hackathon/662 "2019-04-18T17:49:25Z")

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Recently some stars have aligned and we’d like to hold a VTK hackathon on April 18, 2019. We will begin at 9:00am EDT and run through early afternoon. We will reserve a conference room(s) at various Kitware offices (so n…

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## [mpr](https://discourse.vtk.org/t/mpr/782)

<div class="topic-metadata">

**Author:** [@Marco\_Festugato](https://discourse.vtk.org/u/Marco_Festugato)\
**Replies:** 2\
**Last updated:** [April 18, 2019, 5:04pm UTC](https://discourse.vtk.org/t/mpr/782 "2019-04-18T17:04:53Z")

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Hi guys! I want to perform MPR on my 3D volume…how could I do that? Which classes should i use? Is there any example (i dont find any…). Thanks in advance!

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## [for(vtkDataObject \*ds : vtk::Range(multiblock\_ds)) { .. }](https://discourse.vtk.org/t/for-vtkdataobject-ds-vtk-range-multiblock-ds/262)

<div class="topic-metadata">

**Author:** [@allison.vacanti](https://discourse.vtk.org/u/allison.vacanti)\
**Replies:** 7\
**Last updated:** [April 18, 2019, 3:51pm UTC](https://discourse.vtk.org/t/for-vtkdataobject-ds-vtk-range-multiblock-ds/262 "2019-04-18T15:51:18Z")

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Similar to the vtk::DataArrayTupleRange, vtk::DataArrayValueRange, and vtk::Range(vtkCollection\*) helpers added recently, it’s the vtkCompositeDataSet hierarchy’s turn to get C++11 for-range support: https://gitlab.kitw…

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## [Change the colour of the background of vtkImageReslice for areas out of the region of the surface](https://discourse.vtk.org/t/change-the-colour-of-the-background-of-vtkimagereslice-for-areas-out-of-the-region-of-the-surface/776)

<div class="topic-metadata">

**Author:** [@zandarina](https://discourse.vtk.org/u/zandarina)\
**Replies:** 0\
**Last updated:** [April 18, 2019, 11:16am UTC](https://discourse.vtk.org/t/change-the-colour-of-the-background-of-vtkimagereslice-for-areas-out-of-the-region-of-the-surface/776 "2019-04-18T11:16:32Z")

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Hi everybody, I have a doubt, i am getting certain planes of a surface with vtkImageReslice but i found that these regions outside the volume are painted in a weird colour different to black. I read that there is a bug …

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## [How to create a cylinder implicit with specified height](https://discourse.vtk.org/t/how-to-create-a-cylinder-implicit-with-specified-height/681)

<div class="topic-metadata">

**Author:** [@Frank](https://discourse.vtk.org/u/Frank)\
**Replies:** 4\
**Last updated:** [April 14, 2019, 3:40am UTC](https://discourse.vtk.org/t/how-to-create-a-cylinder-implicit-with-specified-height/681 "2019-04-14T03:40:28Z")

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I want to create a implicit cylinder with specified height. From VTK doc, it says The cylinder is infinite in extent. To truncate the cylinder in modeling operations use the vtkImplicitBoolean in combination with clippin…

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## [Labels in VTK js for annotations in image slice](https://discourse.vtk.org/t/labels-in-vtk-js-for-annotations-in-image-slice/685)

<div class="topic-metadata">

**Author:** [@Andrzej\_Marciniak](https://discourse.vtk.org/u/Andrzej_Marciniak)\
**Replies:** 1\
**Last updated:** [April 17, 2019, 5:38pm UTC](https://discourse.vtk.org/t/labels-in-vtk-js-for-annotations-in-image-slice/685 "2019-04-17T17:38:25Z")

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Hi all, Is there any way to add annotations using vtkLabelWidget (or something else) which will work in a way that annotation is visible only on a particular slice? More precisely, is it possible to “attach” label to a …

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## [How to remove the cut of the appended planes around a curve in vtkImageReslice](https://discourse.vtk.org/t/how-to-remove-the-cut-of-the-appended-planes-around-a-curve-in-vtkimagereslice/773)

<div class="topic-metadata">

**Author:** [@zandarina](https://discourse.vtk.org/u/zandarina)\
**Replies:** 0\
**Last updated:** [April 17, 2019, 10:00am UTC](https://discourse.vtk.org/t/how-to-remove-the-cut-of-the-appended-planes-around-a-curve-in-vtkimagereslice/773 "2019-04-17T10:00:07Z")

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Dear all, I have implemented with vtkImageReslice, the append of all especific planes around a curve. It works perfect but i realized that we can see where the cut of the plane is applied: plane 1 appended to plane 2 a…

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## [vtkWarpVector does not work. Any possible bug?](https://discourse.vtk.org/t/vtkwarpvector-does-not-work-any-possible-bug/745)

<div class="topic-metadata">

**Author:** [@zandarina](https://discourse.vtk.org/u/zandarina)\
**Replies:** 6\
**Last updated:** [April 17, 2019, 9:51am UTC](https://discourse.vtk.org/t/vtkwarpvector-does-not-work-any-possible-bug/745 "2019-04-17T09:51:21Z")

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Dear all, I want to scale the spline from its center as an offset (the same it does with the right mouse but we do not have access to use this function). I have tried many ways with no success. I have checked this vtkWa…

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## [No shadows](https://discourse.vtk.org/t/no-shadows/767)

<div class="topic-metadata">

**Author:** [@graphicsmonkey](https://discourse.vtk.org/u/graphicsmonkey)\
**Replies:** 0\
**Last updated:** [April 17, 2019, 3:27am UTC](https://discourse.vtk.org/t/no-shadows/767 "2019-04-17T03:27:27Z")

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I’m trying to get shadows to work with no luck yet. I added the following code based on some of the examples but i’m not seeing anything change. Is there something missing? Many thanks. auto shadows = vtkSmartPointer\<…

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## [parallel rendering in python](https://discourse.vtk.org/t/parallel-rendering-in-python/761)

<div class="topic-metadata">

**Author:** [@clairecita](https://discourse.vtk.org/u/clairecita)\
**Replies:** 1\
**Last updated:** [April 16, 2019, 5:06pm UTC](https://discourse.vtk.org/t/parallel-rendering-in-python/761 "2019-04-16T17:06:59Z")

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Hi, I am trying to do parallele rendering in python but I am having trouble finding a solution. Neither vtkParallelRenderManager() nor vtkCompositeManager() work in python. Does anybody have another solution ?

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## [Python wrapped library and VTK 8.2.0](https://discourse.vtk.org/t/python-wrapped-library-and-vtk-8-2-0/763)

<div class="topic-metadata">

**Author:** [@kit](https://discourse.vtk.org/u/kit)\
**Replies:** 0\
**Last updated:** [April 16, 2019, 11:52am UTC](https://discourse.vtk.org/t/python-wrapped-library-and-vtk-8-2-0/763 "2019-04-16T11:52:05Z")

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Hi, I have a library which links against VTK and uses the python wrapping when I try to compile it against version 8.2.0 it breaks at the python wrapping stage. Would be correct in thinking there are some changes in thi…

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## [Adding metadata to a vtkOpenGLActor](https://discourse.vtk.org/t/adding-metadata-to-a-vtkopenglactor/762)

<div class="topic-metadata">

**Author:** [@msmerps](https://discourse.vtk.org/u/msmerps)\
**Replies:** 3\
**Last updated:** [April 15, 2019, 8:53pm UTC](https://discourse.vtk.org/t/adding-metadata-to-a-vtkopenglactor/762 "2019-04-15T20:53:23Z")

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Hi VTK experts, I would like to add some metadata, a string, to a vtkActor (more specifically a vtkOpenGLActor) so that when a user clicks on it, I can use the metadata to identify what the object represents and act app…

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## [vtkArrowSource](https://discourse.vtk.org/t/vtkarrowsource/759)

<div class="topic-metadata">

**Author:** [@marf](https://discourse.vtk.org/u/marf)\
**Replies:** 1\
**Last updated:** [April 15, 2019, 3:06pm UTC](https://discourse.vtk.org/t/vtkarrowsource/759 "2019-04-15T15:06:03Z")

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After importing the newest vtk.js from https://unpkg.com/vtk.js@8.4.2/dist/vtk.js I realized that the vtkArrowSource is not part of it. Before I used an older version, where it wasn’t included either but I hoped this wou…

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