# Latest

**URL:** https://discourse.vtk.org/latest.md?page=176

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

**Page:** 177

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## [Issues with line rendering](https://discourse.vtk.org/t/issues-with-line-rendering/5752)

<div class="topic-metadata">

**Author:** [@jensgw](https://discourse.vtk.org/u/jensgw)\
**Replies:** 2\
**Last updated:** [May 12, 2021, 12:25pm UTC](https://discourse.vtk.org/t/issues-with-line-rendering/5752 "2021-05-12T12:25:59Z")

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Hi there, does anybody have an idea what happens to the lines in the attached picture? Depending on the viewing angle the thick part of the line moves. The line should be of uniform thickness of 3 px.

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## [The new VTK Examples site is now live](https://discourse.vtk.org/t/the-new-vtk-examples-site-is-now-live/4652)

<div class="topic-metadata">

**Author:** [@amaclean](https://discourse.vtk.org/u/amaclean)\
**Replies:** 70\
**Last updated:** [May 12, 2021, 3:36am UTC](https://discourse.vtk.org/t/the-new-vtk-examples-site-is-now-live/4652 "2021-05-12T03:36:22Z")

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The new VTK Examples site is now live, please use this site: VTKExamples from now on. There have been many changes as outlined below. Special thanks must go to the people who have helped move the examples from Bill Loren…

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## [vtkXYZMolReader](https://discourse.vtk.org/t/vtkxyzmolreader/5761)

<div class="topic-metadata">

**Author:** [@mwestphal](https://discourse.vtk.org/u/mwestphal)\
**Replies:** 1\
**Last updated:** [May 11, 2021, 10:34pm UTC](https://discourse.vtk.org/t/vtkxyzmolreader/5761 "2021-05-11T22:34:16Z")

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There is .xyz molecule reader in VTK. It looks like the older one (vtkXYZMolReader) has less feature and is less tested than the newer one (vtkXYZMolReader2). https://gitlab.kitware.com/vtk/vtk/-/merge\_requests/7954#no…

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## [Remote visualisation. Any advantages of Paraview-based server as it is compared to VTK-based server in multi-user mode?](https://discourse.vtk.org/t/remote-visualisation-any-advantages-of-paraview-based-server-as-it-is-compared-to-vtk-based-server-in-multi-user-mode/5763)

<div class="topic-metadata">

**Author:** [@EMalikova](https://discourse.vtk.org/u/EMalikova)\
**Replies:** 2\
**Last updated:** [May 11, 2021, 6:16pm UTC](https://discourse.vtk.org/t/remote-visualisation-any-advantages-of-paraview-based-server-as-it-is-compared-to-vtk-based-server-in-multi-user-mode/5763 "2021-05-11T18:16:14Z")

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Dear All, I have been playing with launching remote visualisation in multi-user mode and I am trying to understand the possibilities/limitations that I have to deal with depending on the solutions that I chose. In the …

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## [VTKjs release memory](https://discourse.vtk.org/t/vtkjs-release-memory/5707)

<div class="topic-metadata">

**Author:** [@ronzim](https://discourse.vtk.org/u/ronzim)\
**Replies:** 2\
**Last updated:** [May 11, 2021, 2:09pm UTC](https://discourse.vtk.org/t/vtkjs-release-memory/5707 "2021-05-11T14:09:21Z")

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Hi, I would like to ask which is the correct method to release memory allocated by a volumeMapper. I have a genericRenderWindow with just an actor (vtkVolume) and its mapper (vtkVolumeMapper). When I build the scene I …

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## [How to project points to Polydata?](https://discourse.vtk.org/t/how-to-project-points-to-polydata/5694)

<div class="topic-metadata">

**Author:** [@scotsman60](https://discourse.vtk.org/u/scotsman60)\
**Replies:** 7\
**Last updated:** [May 11, 2021, 1:47pm UTC](https://discourse.vtk.org/t/how-to-project-points-to-polydata/5694 "2021-05-11T13:47:11Z")

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Hello!!! I’m using VTK 9.01 and Python 3.8.3 and I’m trying to probe point scalar values from a Polydata to a set of target Points. The target Points lie close to, but not necessarily ON the cells in the polydata and t…

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## [Error when using VTK as server](https://discourse.vtk.org/t/error-when-using-vtk-as-server/5760)

<div class="topic-metadata">

**Author:** [@joaomlap](https://discourse.vtk.org/u/joaomlap)\
**Replies:** 1\
**Last updated:** [May 11, 2021, 12:10pm UTC](https://discourse.vtk.org/t/error-when-using-vtk-as-server/5760 "2021-05-11T12:10:20Z")

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Hi, I’ve been recreating the examples given here: web-project-templates/vue-vtkjs-pvw-template at master · Kitware/web-project-templates · GitHub with React and using Paraview (pvpython) as a server. However, yesterday…

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## [Parallel Projection not working](https://discourse.vtk.org/t/parallel-projection-not-working/5741)

<div class="topic-metadata">

**Author:** [@devngc](https://discourse.vtk.org/u/devngc)\
**Replies:** 11\
**Last updated:** [May 11, 2021, 5:21am UTC](https://discourse.vtk.org/t/parallel-projection-not-working/5741 "2021-05-11T05:21:18Z")

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Hey All, I am trying to make the ParallelProjection work and I am able to create a camera that uses parallel projection bu the I observe that it does not generate flat views that I expect. Following is what I am doing t…

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## [New here](https://discourse.vtk.org/t/new-here/5748)

<div class="topic-metadata">

**Author:** [@drishti\_vishesh](https://discourse.vtk.org/u/drishti_vishesh)\
**Replies:** 1\
**Last updated:** [May 10, 2021, 7:52pm UTC](https://discourse.vtk.org/t/new-here/5748 "2021-05-10T19:52:25Z")

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Hi, Can anyone help me in knowing how I can get started with making custom modules for VTK in Python?

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## [Delaunay triangulation numerically sensitive vtk-9.0.1 vtkDelaunay2D handle large numbers of points System.StackOverflowException](https://discourse.vtk.org/t/delaunay-triangulation-numerically-sensitive-vtk-9-0-1-vtkdelaunay2d-handle-large-numbers-of-points-system-stackoverflowexception/5729)

<div class="topic-metadata">

**Author:** [@yaoganxingwei](https://discourse.vtk.org/u/yaoganxingwei)\
**Replies:** 2\
**Last updated:** [May 10, 2021, 9:22am UTC](https://discourse.vtk.org/t/delaunay-triangulation-numerically-sensitive-vtk-9-0-1-vtkdelaunay2d-handle-large-numbers-of-points-system-stackoverflowexception/5729 "2021-05-10T09:22:38Z")

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In VTK, Delaunay triangulation is numerically sensitive. The vtk-9.0.1 version of vtkDelaunay2D may not be robust enough to reliably handle large numbers of points(For example, 3 million points.). IDE pops up Exception…

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## [How does VTK implement model error detection and repair?](https://discourse.vtk.org/t/how-does-vtk-implement-model-error-detection-and-repair/5731)

<div class="topic-metadata">

**Author:** [@Koly](https://discourse.vtk.org/u/Koly)\
**Replies:** 3\
**Last updated:** [May 10, 2021, 6:13am UTC](https://discourse.vtk.org/t/how-does-vtk-implement-model-error-detection-and-repair/5731 "2021-05-10T06:13:59Z")

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How does VTK implement model error detection and repair? I want to implement the function that is checking bad edges、holes、Bad triangle（including bad orientation、intersections、Overlap）and repairing them. How VTK to do i…

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## [python bindings of vtk based tools](https://discourse.vtk.org/t/python-bindings-of-vtk-based-tools/3003)

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**Author:** [@kayarre](https://discourse.vtk.org/u/kayarre)\
**Replies:** 14\
**Last updated:** [May 8, 2021, 10:01pm UTC](https://discourse.vtk.org/t/python-bindings-of-vtk-based-tools/3003 "2021-05-08T22:01:41Z")

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In reading through this discussion on Remote modules vs external modules I want to create python bindings for a c++ project that heavily depends on VTK, and possibly make a paraview plugin with it. What would be the bes…

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## [Render time in Slicer vs in python code](https://discourse.vtk.org/t/render-time-in-slicer-vs-in-python-code/5639)

<div class="topic-metadata">

**Author:** [@tzodge](https://discourse.vtk.org/u/tzodge)\
**Replies:** 5\
**Last updated:** [May 8, 2021, 10:17am UTC](https://discourse.vtk.org/t/render-time-in-slicer-vs-in-python-code/5639 "2021-05-08T10:17:34Z")

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I am trying to generate DRR of a CT using python code. I am also using Slicer to get an idea of the approximate idea of the transfer function. I observered that just ther rendering part of my code (only the line renWin.…

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## [modify position of points on boundary of polydata surface](https://discourse.vtk.org/t/modify-position-of-points-on-boundary-of-polydata-surface/5716)

<div class="topic-metadata">

**Author:** [@bistek](https://discourse.vtk.org/u/bistek)\
**Replies:** 1\
**Last updated:** [May 7, 2021, 4:40pm UTC](https://discourse.vtk.org/t/modify-position-of-points-on-boundary-of-polydata-surface/5716 "2021-05-07T16:40:33Z")

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Hello, I am trying to modify the coordinates of points on the boundary of a triangulated surface (polydata made of triangle cells), in order to slightly expand some sections of the boundary in a direction that is perpend…

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## [Passing python vtk\_ptr to C++ Failed](https://discourse.vtk.org/t/passing-python-vtk-ptr-to-c-failed/5713)

<div class="topic-metadata">

**Author:** [@WailmerPail](https://discourse.vtk.org/u/WailmerPail)\
**Replies:** 6\
**Last updated:** [May 7, 2021, 3:39pm UTC](https://discourse.vtk.org/t/passing-python-vtk-ptr-to-c-failed/5713 "2021-05-07T15:39:10Z")

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Hello Team, I tried to pass the py\_vtk\_ptr to cpp\_vtk for modifiying the value rapidly. I used the method from pletzer/vtkpythoncpp, like ///==== addr = int(pdata.GetAddressAsString(‘vtkPolyData’)\[5:\], 16) lib.foo(c…

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## [VTK 6.3.0](https://discourse.vtk.org/t/vtk-6-3-0/5734)

<div class="topic-metadata">

**Author:** [@colinbannister](https://discourse.vtk.org/u/colinbannister)\
**Replies:** 2\
**Last updated:** [May 7, 2021, 1:52pm UTC](https://discourse.vtk.org/t/vtk-6-3-0/5734 "2021-05-07T13:52:11Z")

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I am trying to build ITK-snap which has VTK as a pre-requisite.BuildingITK-SNAP. The version recommended is 6.3.0, but I can’t find a download. Can anyone help ? Thanks in advance Colin

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## [Clipping on UniformGrid (Color errors)](https://discourse.vtk.org/t/clipping-on-uniformgrid-color-errors/5724)

<div class="topic-metadata">

**Author:** [@Guillaume\_Gillet](https://discourse.vtk.org/u/Guillaume_Gillet)\
**Replies:** 0\
**Last updated:** [May 7, 2021, 8:22am UTC](https://discourse.vtk.org/t/clipping-on-uniformgrid-color-errors/5724 "2021-05-07T08:22:32Z")

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So i’m coming here because i’m actually working on performance enhancement, and i’m now asked to add clipping to my uniformgrid exampls, but i’m facing two problems, if i use the raw grid and vtkClipDataSet i have my col…

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## [When I use QVTKOpenGLStereoWidget](https://discourse.vtk.org/t/when-i-use-qvtkopenglstereowidget/5723)

<div class="topic-metadata">

**Author:** [@loufear](https://discourse.vtk.org/u/loufear)\
**Replies:** 1\
**Last updated:** [May 7, 2021, 8:18am UTC](https://discourse.vtk.org/t/when-i-use-qvtkopenglstereowidget/5723 "2021-05-07T08:18:14Z")

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QVTKOpenGLStereoWidget actor ghosting \* When mouse events are triggered

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## [Streamtracer with CSV data](https://discourse.vtk.org/t/streamtracer-with-csv-data/5720)

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**Author:** [@Ondrej\_Tkadlec](https://discourse.vtk.org/u/Ondrej_Tkadlec)\
**Replies:** 0\
**Last updated:** [May 6, 2021, 8:00pm UTC](https://discourse.vtk.org/t/streamtracer-with-csv-data/5720 "2021-05-06T20:00:31Z")

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Hi, I’m trying to make 3D streamtracer with data from CSV file. It has 3 columns x,y,z for points in 3D space and 3 columns vx,vy,vz for the 3D vector that belongs to that point. I’m able to plot glyph plot but I’m unab…

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## [Darker version of lookup table for backfaces of vtkPolyData?](https://discourse.vtk.org/t/darker-version-of-lookup-table-for-backfaces-of-vtkpolydata/2108)

<div class="topic-metadata">

**Author:** [@maleike](https://discourse.vtk.org/u/maleike)\
**Replies:** 8\
**Last updated:** [May 6, 2021, 6:24pm UTC](https://discourse.vtk.org/t/darker-version-of-lookup-table-for-backfaces-of-vtkpolydata/2108 "2021-05-06T18:24:20Z")

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I am using vtkPolyData for visualization of surfaces in my application. By default I derive a backface color for the object as a ‘darker’ version of the frontface color so that users can easily tell apart inside and outs…

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## [Animation & actor-\>SetMapper](https://discourse.vtk.org/t/animation-actor-setmapper/5704)

<div class="topic-metadata">

**Author:** [@nparent](https://discourse.vtk.org/u/nparent)\
**Replies:** 1\
**Last updated:** [May 6, 2021, 3:07pm UTC](https://discourse.vtk.org/t/animation-actor-setmapper/5704 "2021-05-06T15:07:08Z")

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Hi, I would like to create animations in which I change the vtkMapper of the actor. Basically, I have a curve (rod) that I want to animate. It is named yarn and it evolves in time by calling yarn-\>step() and then I ca…

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## [Color Volume Rendering: vtkDataArray Indexing](https://discourse.vtk.org/t/color-volume-rendering-vtkdataarray-indexing/5695)

<div class="topic-metadata">

**Author:** [@Alireza](https://discourse.vtk.org/u/Alireza)\
**Replies:** 5\
**Last updated:** [May 5, 2021, 4:38pm UTC](https://discourse.vtk.org/t/color-volume-rendering-vtkdataarray-indexing/5695 "2021-05-05T16:38:46Z")

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I’m trying to do a color volume rendering for a 3D segmentation that has RGB values. To have a color image, I started by drawing a Red box, for some reason I’m not able to get a color volume rendering of it at all. My …

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## [Forcing rendering](https://discourse.vtk.org/t/forcing-rendering/5692)

<div class="topic-metadata">

**Author:** [@Luis\_Carlos\_Carneiro](https://discourse.vtk.org/u/Luis_Carlos_Carneiro)\
**Replies:** 1\
**Last updated:** [May 4, 2021, 4:04pm UTC](https://discourse.vtk.org/t/forcing-rendering/5692 "2021-05-04T16:04:56Z")

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Dear All, I do the rendering of several volumes in same 3D image. Some of them are over the others and shadow the previous rendered ones. How I force re-render the previous ones (volumes) to appear the shadowed areas?…

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## [Performance degrade for more than 10000 actor](https://discourse.vtk.org/t/performance-degrade-for-more-than-10000-actor/5683)

<div class="topic-metadata">

**Author:** [@Anil\_Singh](https://discourse.vtk.org/u/Anil_Singh)\
**Replies:** 7\
**Last updated:** [May 4, 2021, 3:00pm UTC](https://discourse.vtk.org/t/performance-degrade-for-more-than-10000-actor/5683 "2021-05-04T15:00:09Z")

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Hello Team, I tried to support large actor count with individual interaction. Performance degrade when actor count goes beyond 1000 actor. Please support me on this. I need to move individual sphere with mouse as same t…

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## [Co-planar surfaces rendered differently depending on depth peeling activation](https://discourse.vtk.org/t/co-planar-surfaces-rendered-differently-depending-on-depth-peeling-activation/5616)

<div class="topic-metadata">

**Author:** [@afa](https://discourse.vtk.org/u/afa)\
**Replies:** 5\
**Last updated:** [May 4, 2021, 2:38pm UTC](https://discourse.vtk.org/t/co-planar-surfaces-rendered-differently-depending-on-depth-peeling-activation/5616 "2021-05-04T14:38:53Z")

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Hello, I often find myself in a situation where I have to deal with co-planar surfaces. The render differs depending whether or not I am using depth peeling. Occlussion or composite change nothing in the result. I am …

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## [To render the real size of actor without zooming](https://discourse.vtk.org/t/to-render-the-real-size-of-actor-without-zooming/5385)

<div class="topic-metadata">

**Author:** [@zandarina](https://discourse.vtk.org/u/zandarina)\
**Replies:** 3\
**Last updated:** [May 4, 2021, 1:39pm UTC](https://discourse.vtk.org/t/to-render-the-real-size-of-actor-without-zooming/5385 "2021-05-04T13:39:57Z")

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I am rendering circles in the position of the mouse. My surprise is if I zoom in the scene and I add a circle they become larger than the original one. If it has a radius of three I would like to see the circle of radius…

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## [add label to clicked 3D position](https://discourse.vtk.org/t/add-label-to-clicked-3d-position/3828)

<div class="topic-metadata">

**Author:** [@mohammad\_jalili](https://discourse.vtk.org/u/mohammad_jalili)\
**Replies:** 1\
**Last updated:** [May 4, 2021, 1:37pm UTC](https://discourse.vtk.org/t/add-label-to-clicked-3d-position/3828 "2021-05-04T13:37:33Z")

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Hello everyone. I have rendered a 3D DICOM and now I want to add vtkTextActor3D in some 3D position when user clicks. How to do that?

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## [Render window stuck after setting interpolation type to linear](https://discourse.vtk.org/t/render-window-stuck-after-setting-interpolation-type-to-linear/5702)

<div class="topic-metadata">

**Author:** [@xxyyy159](https://discourse.vtk.org/u/xxyyy159)\
**Replies:** 0\
**Last updated:** [May 4, 2021, 1:32pm UTC](https://discourse.vtk.org/t/render-window-stuck-after-setting-interpolation-type-to-linear/5702 "2021-05-04T13:32:57Z")

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Hi all, I’m using vtkCameraInterpolator for some program and I find an example here(link below). https://kitware.github.io/vtk-examples/site/Cxx/Rendering/InterpolateCamera/ After setting the interpolation type to lin…

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## [How can I obtain the intersection line from a isosurface which is cut by other surface?](https://discourse.vtk.org/t/how-can-i-obtain-the-intersection-line-from-a-isosurface-which-is-cut-by-other-surface/5691)

<div class="topic-metadata">

**Author:** [@DavidMiraut](https://discourse.vtk.org/u/DavidMiraut)\
**Replies:** 5\
**Last updated:** [May 4, 2021, 1:05pm UTC](https://discourse.vtk.org/t/how-can-i-obtain-the-intersection-line-from-a-isosurface-which-is-cut-by-other-surface/5691 "2021-05-04T13:05:09Z")

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Hello, I would like to obtain the representation of the intersection of an isosurface with other surface (in this example code, it is just a plane). The isosurface is extrated from a volume image via vtkMarchingCubes, v…

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## [pypi vtk on macOS 11 Big Sur](https://discourse.vtk.org/t/pypi-vtk-on-macos-11-big-sur/5647)

<div class="topic-metadata">

**Author:** [@noamb](https://discourse.vtk.org/u/noamb)\
**Replies:** 2\
**Last updated:** [May 4, 2021, 12:54pm UTC](https://discourse.vtk.org/t/pypi-vtk-on-macos-11-big-sur/5647 "2021-05-04T12:54:47Z")

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What’s the current status of python vtk installation via pip on the latest macOS (11)? I’m reluctant to upgrade because I’ve heard rumors that it’s not working, and the binary files on pypi do seem a bit old to support …

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