# Latest

**URL:** https://discourse.vtk.org/latest.md?page=160

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

**Page:** 161

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## [Event Processing order when Vtk Application is slow](https://discourse.vtk.org/t/event-processing-order-when-vtk-application-is-slow/6758)

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**Author:** [@sateesh](https://discourse.vtk.org/u/sateesh)\
**Replies:** 2\
**Last updated:** [October 7, 2021, 5:44am UTC](https://discourse.vtk.org/t/event-processing-order-when-vtk-application-is-slow/6758 "2021-10-07T05:44:48Z")

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Hi, There seems to be some issue with the event processing order using VTK version 8.1.0 and Qt version 5.10. This occurs when there are more graphics rendered in QVTKOpenGLWidget based window, which makes the applicat…

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## [VTK-9.0.3-1 is asserting with a simple cube FEM in FreeCAD](https://discourse.vtk.org/t/vtk-9-0-3-1-is-asserting-with-a-simple-cube-fem-in-freecad/6749)

<div class="topic-metadata">

**Author:** [@linux\_guy](https://discourse.vtk.org/u/linux_guy)\
**Replies:** 24\
**Last updated:** [October 7, 2021, 12:11am UTC](https://discourse.vtk.org/t/vtk-9-0-3-1-is-asserting-with-a-simple-cube-fem-in-freecad/6749 "2021-10-07T00:11:48Z")

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I’m not sure where to report a bug/issue, so here I am. Full description of the issue is here: https://forum.freecadweb.org/viewtopic.php?f=18&t=62566&p=537350#p537350 How should I proceed ?

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## [Clarifications and Modifications of Global Ids](https://discourse.vtk.org/t/clarifications-and-modifications-of-global-ids/6746)

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**Author:** [@Yohann\_Bearzi](https://discourse.vtk.org/u/Yohann_Bearzi)\
**Replies:** 5\
**Last updated:** [October 6, 2021, 2:23pm UTC](https://discourse.vtk.org/t/clarifications-and-modifications-of-global-ids/6746 "2021-10-06T14:23:55Z")

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This post follows this discussion. In VTK, cell data and point data hold a concept called “attribute types”. Some of the most noticeable ones are Normals, Scalars, and GlobalIds. Global ids can be generated using vtkGe…

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## [How to make display size of an actor independent from zoom level with vtk.js ?](https://discourse.vtk.org/t/how-to-make-display-size-of-an-actor-independent-from-zoom-level-with-vtk-js/6588)

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**Author:** [@toro](https://discourse.vtk.org/u/toro)\
**Replies:** 4\
**Last updated:** [October 6, 2021, 8:08am UTC](https://discourse.vtk.org/t/how-to-make-display-size-of-an-actor-independent-from-zoom-level-with-vtk-js/6588 "2021-10-06T08:08:31Z")

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In a scene, I want the zoom action to effectively change the rendered size of most of the actors in the scene (typically those built from vtkCubeSource), except some of them (for example, built from a vtkSphereSource) fo…

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## [Why the quality of volume rendering in vtk.js is so much worse than in native vtk?](https://discourse.vtk.org/t/why-the-quality-of-volume-rendering-in-vtk-js-is-so-much-worse-than-in-native-vtk/6767)

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**Author:** [@take5v](https://discourse.vtk.org/u/take5v)\
**Replies:** 7\
**Last updated:** [October 5, 2021, 8:00pm UTC](https://discourse.vtk.org/t/why-the-quality-of-volume-rendering-in-vtk-js-is-so-much-worse-than-in-native-vtk/6767 "2021-10-05T20:00:37Z")

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Hi, I really appreciate the work done in porting vtk to the web and I hope vtk.js project will flourish in the future. However, currently, there is a great gap in the quality of volume rendering between native vtk and v…

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## [How to draw perfectly uniform stipple lines](https://discourse.vtk.org/t/how-to-draw-perfectly-uniform-stipple-lines/6750)

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**Author:** [@Seun](https://discourse.vtk.org/u/Seun)\
**Replies:** 0\
**Last updated:** [October 1, 2021, 7:26pm UTC](https://discourse.vtk.org/t/how-to-draw-perfectly-uniform-stipple-lines/6750 "2021-10-01T19:26:55Z")

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Hello everyone, I was wondering if I could get some help with rendering stippled lines. I’m currently using a vtkActor attached to a PolyDataMapper of which I customise the Shader property in order to get the desired ef…

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## [VTK windows not showing until I move mouse](https://discourse.vtk.org/t/vtk-windows-not-showing-until-i-move-mouse/6745)

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**Author:** [@Kevin\_Sweeney](https://discourse.vtk.org/u/Kevin_Sweeney)\
**Replies:** 1\
**Last updated:** [October 5, 2021, 2:06pm UTC](https://discourse.vtk.org/t/vtk-windows-not-showing-until-i-move-mouse/6745 "2021-10-05T14:06:58Z")

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Probably a simple question, but some of my windows are not showing anything until I move/click my mouse over them. It could be due to the setup that I have the code in, but the code below shows a snippet. What am I f…

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## [vtk.js in medical image processing](https://discourse.vtk.org/t/vtk-js-in-medical-image-processing/5946)

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**Author:** [@zrxiaojie](https://discourse.vtk.org/u/zrxiaojie)\
**Replies:** 6\
**Last updated:** [October 5, 2021, 2:04pm UTC](https://discourse.vtk.org/t/vtk-js-in-medical-image-processing/5946 "2021-10-05T14:04:32Z")

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Hi, I have a question with vtk.js in medical image processing. vtk.js has a powerful image display function. But for processing medical images like segmentation on the web, is this feasible? When we develop desktop softw…

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## [How to pass geo from vtk to netgen & pass mesh from netgen to vtk directly without needing to exporting/read file?](https://discourse.vtk.org/t/how-to-pass-geo-from-vtk-to-netgen-pass-mesh-from-netgen-to-vtk-directly-without-needing-to-exporting-read-file/6766)

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**Author:** [@AlexLuya](https://discourse.vtk.org/u/AlexLuya)\
**Replies:** 1\
**Last updated:** [October 5, 2021, 10:41am UTC](https://discourse.vtk.org/t/how-to-pass-geo-from-vtk-to-netgen-pass-mesh-from-netgen-to-vtk-directly-without-needing-to-exporting-read-file/6766 "2021-10-05T10:41:45Z")

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Following code can export meshing result as vtu file from netgen import occ, meshing from ngsolve.utils import \* from vtkmodules.vtkIOXML import vtkXMLUnstructuredGridReader from ngsolve.comp import \* from ngsolve.solv…

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## [Unable to cast from double\* to vtkSmartPointer\<double\>](https://discourse.vtk.org/t/unable-to-cast-from-double-to-vtksmartpointer-double/6723)

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**Author:** [@huaweiping](https://discourse.vtk.org/u/huaweiping)\
**Replies:** 6\
**Last updated:** [October 5, 2021, 10:36am UTC](https://discourse.vtk.org/t/unable-to-cast-from-double-to-vtksmartpointer-double/6723 "2021-10-05T10:36:07Z")

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Hi, Today I find a problem about casting a raw pointer to a SmartPointer. I’m actually randomly facing a segmentation fault when just simply allocating vector (which is very rare I guess) and I can’t figure out the reas…

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## [How to manage several polydata at the same time](https://discourse.vtk.org/t/how-to-manage-several-polydata-at-the-same-time/6761)

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**Author:** [@Texas](https://discourse.vtk.org/u/Texas)\
**Replies:** 1\
**Last updated:** [October 4, 2021, 5:10pm UTC](https://discourse.vtk.org/t/how-to-manage-several-polydata-at-the-same-time/6761 "2021-10-04T17:10:37Z")

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Hello, I have a mesh named my\_initial\_mesh with, let say for the example 6 cells named \[0 1 2 3 4 5\] I would like to delete 2 cells and plot the results of both at the same time so i do : my\_troncated\_mesh=my\_mesh m…

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## [positioning and scaling of Actor2D with image](https://discourse.vtk.org/t/positioning-and-scaling-of-actor2d-with-image/6754)

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**Author:** [@rdbrn](https://discourse.vtk.org/u/rdbrn)\
**Replies:** 10\
**Last updated:** [October 4, 2021, 2:16pm UTC](https://discourse.vtk.org/t/positioning-and-scaling-of-actor2d-with-image/6754 "2021-10-04T14:16:11Z")

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I’m trying to display a static image in on of the corners of the screen. Like a company logo or some additional information (see Adding a logo-widget · Issue #474 · marcomusy/vedo (github.com)) . Easiest seems to use a …

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## [Export scene](https://discourse.vtk.org/t/export-scene/6731)

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**Author:** [@naffrancois](https://discourse.vtk.org/u/naffrancois)\
**Replies:** 2\
**Last updated:** [October 3, 2021, 8:17am UTC](https://discourse.vtk.org/t/export-scene/6731 "2021-10-03T08:17:46Z")

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Dear all, Please forgive me if this question has been already answered, I could not find clear explanations in other threads. I am currently working with a simple java-vtk window in which I do several things like set i…

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## [Converting physical coordinates to id coordinates](https://discourse.vtk.org/t/converting-physical-coordinates-to-id-coordinates/6753)

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**Author:** [@ugursasun](https://discourse.vtk.org/u/ugursasun)\
**Replies:** 0\
**Last updated:** [October 2, 2021, 1:12pm UTC](https://discourse.vtk.org/t/converting-physical-coordinates-to-id-coordinates/6753 "2021-10-02T13:12:30Z")

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Hello. I am a beginner VTK user and I need an immediate help. I am working on a extension on an old code. As I understand, I need to give Pick() function id coordinates( back then, code was working properly with id coor…

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## [\[vtk.js\] Using image stream with a RenderWindow instead of a full screen renderer](https://discourse.vtk.org/t/vtk-js-using-image-stream-with-a-renderwindow-instead-of-a-full-screen-renderer/6737)

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**Author:** [@ev-elucidbio](https://discourse.vtk.org/u/ev-elucidbio)\
**Replies:** 3\
**Last updated:** [October 1, 2021, 5:00pm UTC](https://discourse.vtk.org/t/vtk-js-using-image-stream-with-a-renderwindow-instead-of-a-full-screen-renderer/6737 "2021-10-01T17:00:27Z")

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Hi, I’m trying to follow the imagestream demo, but using two render windows instead of the full screen renderer. Under the hood, it looks like the full screen renderer uses the render window to attach itself to the body…

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## [Python IDE autocompletion for upcoming VTK 9.1](https://discourse.vtk.org/t/python-ide-autocompletion-for-upcoming-vtk-9-1/6708)

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**Author:** [@dgobbi](https://discourse.vtk.org/u/dgobbi)\
**Replies:** 30\
**Last updated:** [October 1, 2021, 4:04am UTC](https://discourse.vtk.org/t/python-ide-autocompletion-for-upcoming-vtk-9-1/6708 "2021-10-01T04:04:40Z")

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Hi all, just today I merged a patch into VTK-master to improve the vtk-python method descriptors and docstrings. This should help autocompletion and hinting for ipython and jupyter. Anyone who wants to try it out, plea…

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## [Vtk point set registration](https://discourse.vtk.org/t/vtk-point-set-registration/2599)

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**Author:** [@ShaneKirkbride](https://discourse.vtk.org/u/ShaneKirkbride)\
**Replies:** 11\
**Last updated:** [October 1, 2021, 1:41am UTC](https://discourse.vtk.org/t/vtk-point-set-registration/2599 "2021-10-01T01:41:09Z")

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Does the ICP algorithm support deformable or non-rigid meshes?

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## [Unable to customize mouse gestures in vtkInteractorStyleRubberBand3D](https://discourse.vtk.org/t/unable-to-customize-mouse-gestures-in-vtkinteractorstylerubberband3d/6740)

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**Author:** [@scotsman60](https://discourse.vtk.org/u/scotsman60)\
**Replies:** 0\
**Last updated:** [September 30, 2021, 10:13pm UTC](https://discourse.vtk.org/t/unable-to-customize-mouse-gestures-in-vtkinteractorstylerubberband3d/6740 "2021-09-30T22:13:14Z")

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I’m using Python 3.8 and vtk 9.0.1 and attempting to customize a vtkInteractorStyleRubberBand3D to support custom view manipulation mouse button bindings and support rubber band picking and rubber band zoom. I was previ…

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## [Vtu xsd format](https://discourse.vtk.org/t/vtu-xsd-format/6733)

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**Author:** [@hamid\_badi](https://discourse.vtk.org/u/hamid_badi)\
**Replies:** 0\
**Last updated:** [September 30, 2021, 3:43pm UTC](https://discourse.vtk.org/t/vtu-xsd-format/6733 "2021-09-30T15:43:10Z")

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Hi, Is there a xsd vtu file format ? I can’t find a precise description of the vtu file format. Best regards.

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## [Issues with vtkImageCanvasSource2D](https://discourse.vtk.org/t/issues-with-vtkimagecanvassource2d/6729)

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**Author:** [@kynetyk](https://discourse.vtk.org/u/kynetyk)\
**Replies:** 1\
**Last updated:** [September 30, 2021, 2:20pm UTC](https://discourse.vtk.org/t/issues-with-vtkimagecanvassource2d/6729 "2021-09-30T14:20:02Z")

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Hello! I’m writing a PyQt5 application to draw on medical images using vtkImageCanvasSource2D, however I’m having issues with oriented images. It seems that when I connect a vtkImageCanvasSource2D to a mapper using Get…

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## [Differences in brightness rendering with Xvfb](https://discourse.vtk.org/t/differences-in-brightness-rendering-with-xvfb/6680)

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**Author:** [@ian\_glover](https://discourse.vtk.org/u/ian_glover)\
**Replies:** 1\
**Last updated:** [September 30, 2021, 2:14pm UTC](https://discourse.vtk.org/t/differences-in-brightness-rendering-with-xvfb/6680 "2021-09-30T14:14:47Z")

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I am having a problem with some unit tests we have to check behaviour of our code applying transformations and displaying the results using vtkImageResliceToColors. The test code renders to image and saves the result as…

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## [vtk.js interactorStyleManipulator constrain rotation](https://discourse.vtk.org/t/vtk-js-interactorstylemanipulator-constrain-rotation/6712)

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**Author:** [@siebe](https://discourse.vtk.org/u/siebe)\
**Replies:** 2\
**Last updated:** [September 30, 2021, 12:37pm UTC](https://discourse.vtk.org/t/vtk-js-interactorstylemanipulator-constrain-rotation/6712 "2021-09-30T12:37:40Z")

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Hi, I’m using a vtkRenderWindowInteractor with the vtkInteractorStyleManipulator style applied to it. This allows to rotate the 3D view using mouse gestures. I was wandering if there is a way to constrain the 3D rotati…

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## [vtk-examples Repository Scraping](https://discourse.vtk.org/t/vtk-examples-repository-scraping/6730)

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**Author:** [@amaclean](https://discourse.vtk.org/u/amaclean)\
**Replies:** 0\
**Last updated:** [September 30, 2021, 7:12am UTC](https://discourse.vtk.org/t/vtk-examples-repository-scraping/6730 "2021-09-30T07:12:55Z")

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I have just completed a major rewrite of ScrapeRepo.py. This script generates all the markdown files for the web. Please let me know it you see any issues on the web pages e.g missing/bad links or missing images. Here …

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## [Problem with vtkLinearExtrusionFilter](https://discourse.vtk.org/t/problem-with-vtklinearextrusionfilter/6721)

<div class="topic-metadata">

**Author:** [@Beheshtian](https://discourse.vtk.org/u/Beheshtian)\
**Replies:** 2\
**Last updated:** [September 29, 2021, 11:39pm UTC](https://discourse.vtk.org/t/problem-with-vtklinearextrusionfilter/6721 "2021-09-29T23:39:12Z")

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Hi all, I wanna create a 3D object from a surface. I’m using vtkLinearExtusionFilter to extrude a surface but when I do that see some holes on extrude output and some bad edges. see the pic below. here is my code: …

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## [Vtkpolydata inside another one](https://discourse.vtk.org/t/vtkpolydata-inside-another-one/6725)

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**Author:** [@Hanxin\_Hua](https://discourse.vtk.org/u/Hanxin_Hua)\
**Replies:** 0\
**Last updated:** [September 29, 2021, 8:06pm UTC](https://discourse.vtk.org/t/vtkpolydata-inside-another-one/6725 "2021-09-29T20:06:59Z")

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Hello Everyone, I have a question. I define two polydata p1 and p2. If p2 is in p1, then I do nothing. If p2 has some part outside p1, then I use vtkBooleanOperationPolyDataFilter to calculate the union of p1 and p2 a…

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## [Delaunay2/3D VTK.js](https://discourse.vtk.org/t/delaunay2-3d-vtk-js/6692)

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**Author:** [@Kevin\_Sweeney](https://discourse.vtk.org/u/Kevin_Sweeney)\
**Replies:** 15\
**Last updated:** [September 29, 2021, 6:22pm UTC](https://discourse.vtk.org/t/delaunay2-3d-vtk-js/6692 "2021-09-29T18:22:06Z")

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Firstly, as a confirmation, am I correct in saying that Delaunay2/3D is not currently available in VTK.js? Within a project, would it be possible to create the Delaunay actor / mapper in Python for a given set of points…

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## [Trackpad Interactions](https://discourse.vtk.org/t/trackpad-interactions/6598)

<div class="topic-metadata">

**Author:** [@coffeecup](https://discourse.vtk.org/u/coffeecup)\
**Replies:** 5\
**Last updated:** [September 29, 2021, 4:49pm UTC](https://discourse.vtk.org/t/trackpad-interactions/6598 "2021-09-29T16:49:14Z")

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Hi, I am trying to understand which Events correspond to trackpad events. When I create a vtkSphereWidget and click on it using my Mac trackpad, it lights up - so I know vtk can accept trackpad events. However, when I…

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## [Creating a new vtkDataSet from an existing vtkDataSet](https://discourse.vtk.org/t/creating-a-new-vtkdataset-from-an-existing-vtkdataset/5870)

<div class="topic-metadata">

**Author:** [@huaweiping](https://discourse.vtk.org/u/huaweiping)\
**Replies:** 2\
**Last updated:** [September 29, 2021, 9:01am UTC](https://discourse.vtk.org/t/creating-a-new-vtkdataset-from-an-existing-vtkdataset/5870 "2021-09-29T09:01:51Z")

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Hello, I just met a question about creating a new vtkDataSet from an existing vtkDataSet. I have an original dataset A vtkSmartPointer\<vtkDataSet\> A = CreateDataSetA(); And now I want to create a deepcopy of the DataS…

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## [No Image when slicing along YZ or XZ plane](https://discourse.vtk.org/t/no-image-when-slicing-along-yz-or-xz-plane/6695)

<div class="topic-metadata">

**Author:** [@Birkl](https://discourse.vtk.org/u/Birkl)\
**Replies:** 2\
**Last updated:** [September 29, 2021, 8:39am UTC](https://discourse.vtk.org/t/no-image-when-slicing-along-yz-or-xz-plane/6695 "2021-09-29T08:39:23Z")

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Hi everyone, I’m currently working on MIPs for the 3 anatomical planes but I ran into some issues with sagittal and frontal. For those two I only get a completely black image as the output. Below is the function to g…

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## [vtkGeometryFilter and its evil spawn vtkDataSetSurfaceFilter](https://discourse.vtk.org/t/vtkgeometryfilter-and-its-evil-spawn-vtkdatasetsurfacefilter/4083)

<div class="topic-metadata">

**Author:** [@will.schroeder](https://discourse.vtk.org/u/will.schroeder)\
**Replies:** 5\
**Last updated:** [September 28, 2021, 5:27pm UTC](https://discourse.vtk.org/t/vtkgeometryfilter-and-its-evil-spawn-vtkdatasetsurfacefilter/4083 "2021-09-28T17:27:02Z")

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Summary: Soon I will push a revamped version of vtkGeometryFilter. Since it is used heavily in VTK, I wouldn’t be surprised to see some issues pop up (despite passing all tests). Please let me know if you see anything u…

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