# Latest

**URL:** https://discourse.vtk.org/latest.md?page=184

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

**Page:** 185

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## [vtkWarpScalar produces hexagonal peaks](https://discourse.vtk.org/t/vtkwarpscalar-produces-hexagonal-peaks/5208)

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**Author:** [@cricket](https://discourse.vtk.org/u/cricket)\
**Replies:** 7\
**Last updated:** [February 23, 2021, 11:15pm UTC](https://discourse.vtk.org/t/vtkwarpscalar-produces-hexagonal-peaks/5208 "2021-02-23T23:15:23Z")

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Hi, I am trying to create a simple height map from a numpy array. Everything is zero, except for a peak in the center. The peak is hexagonal, and tilted, and so it’s not symmetrical. I want to create a spectrogram, b…

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## [Help with XMLPStructuredGrid writer](https://discourse.vtk.org/t/help-with-xmlpstructuredgrid-writer/5202)

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**Author:** [@Daniel\_Coxe](https://discourse.vtk.org/u/Daniel_Coxe)\
**Replies:** 1\
**Last updated:** [February 23, 2021, 6:50pm UTC](https://discourse.vtk.org/t/help-with-xmlpstructuredgrid-writer/5202 "2021-02-23T18:50:25Z")

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I am new here and was wondering if I could get a hand with this. I did a search for “parallel” and there are a lot of questions but not a whole lot of answers. I have largish 3D datasets that I need to visualize (turbu…

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## [problem in using vtkextrusion for 3D files](https://discourse.vtk.org/t/problem-in-using-vtkextrusion-for-3d-files/5236)

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**Author:** [@Amir\_Hossein\_Zeydi](https://discourse.vtk.org/u/Amir_Hossein_Zeydi)\
**Replies:** 1\
**Last updated:** [February 23, 2021, 4:36pm UTC](https://discourse.vtk.org/t/problem-in-using-vtkextrusion-for-3d-files/5236 "2021-02-23T16:36:33Z")

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I used vtkextrusion to extrude a 3D STL of bone. But after using the code below it just duplicated it for me. this is my code: import vtk filename = "the file" #First STL file reader = vtk.vtkSTLReader() reader.Set…

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## [Project STL file on a surface](https://discourse.vtk.org/t/project-stl-file-on-a-surface/5235)

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**Author:** [@Amir\_Hossein\_Zeydi](https://discourse.vtk.org/u/Amir_Hossein_Zeydi)\
**Replies:** 0\
**Last updated:** [February 23, 2021, 2:09pm UTC](https://discourse.vtk.org/t/project-stl-file-on-a-surface/5235 "2021-02-23T14:09:48Z")

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I need a 2D projection of a STL file. It’s like the clipping method in VTK python but I need biggest 2D surface of that STL.

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## [Remove displayed points delimited by 6 planes](https://discourse.vtk.org/t/remove-displayed-points-delimited-by-6-planes/5183)

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**Author:** [@Luis\_Carlos\_Carneiro](https://discourse.vtk.org/u/Luis_Carlos_Carneiro)\
**Replies:** 7\
**Last updated:** [February 23, 2021, 1:23pm UTC](https://discourse.vtk.org/t/remove-displayed-points-delimited-by-6-planes/5183 "2021-02-23T13:23:11Z")

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Dear All, Which the best way to remove displayed points of a volume, delimited by 6 planes? I want to give 6x3 points (x,y,z each point) defining the planes and remove the points inside. Each plane defined by 3 points. …

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## [VTK Enclosed points. Wrong results](https://discourse.vtk.org/t/vtk-enclosed-points-wrong-results/5231)

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**Author:** [@IVarha](https://discourse.vtk.org/u/IVarha)\
**Replies:** 4\
**Last updated:** [February 22, 2021, 10:08pm UTC](https://discourse.vtk.org/t/vtk-enclosed-points-wrong-results/5231 "2021-02-22T22:08:58Z")

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Dear VTK community, I am trying check which points of my data located inside of the mesh. I use VTKEnclosedPoints to perform this check however it produce wrong results for my data (All points are off the dataset while v…

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## [Missing (not found) function/object](https://discourse.vtk.org/t/missing-not-found-function-object/5022)

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**Author:** [@Luis\_Carlos\_Carneiro](https://discourse.vtk.org/u/Luis_Carlos_Carneiro)\
**Replies:** 22\
**Last updated:** [February 22, 2021, 8:49pm UTC](https://discourse.vtk.org/t/missing-not-found-function-object/5022 "2021-02-22T20:49:06Z")

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Dear All, Where is defined “onRemoteMouseEvent” in model.interactorStyle.onRemoteMouseEvent((e) =\> { in …node\_modules\\vtk.js\\Sources\\Rendering\\Misc\\RemoteView\\index.js Thanks, Luís Gonçalves

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## [Retaining the color of the 2d image used for Volume Rendering.](https://discourse.vtk.org/t/retaining-the-color-of-the-2d-image-used-for-volume-rendering/5230)

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**Author:** [@Saptarshi\_Paul](https://discourse.vtk.org/u/Saptarshi_Paul)\
**Replies:** 8\
**Last updated:** [February 22, 2021, 6:25pm UTC](https://discourse.vtk.org/t/retaining-the-color-of-the-2d-image-used-for-volume-rendering/5230 "2021-02-22T18:25:34Z")

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Hello Everyone: I am very new to volume rendering, and I was able to render a 3d Volume using stack of 2D images in png format. The resultant 3dVolume is in grey scale, but I want the color of the volume to be same as …

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## [About performance of method vtkImageViewer2.SetSlice(int)](https://discourse.vtk.org/t/about-performance-of-method-vtkimageviewer2-setslice-int/4803)

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**Author:** [@learn\_forever](https://discourse.vtk.org/u/learn_forever)\
**Replies:** 20\
**Last updated:** [February 22, 2021, 3:44pm UTC](https://discourse.vtk.org/t/about-performance-of-method-vtkimageviewer2-setslice-int/4803 "2021-02-22T15:44:43Z")

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Hi, I did some performance profilling for the method vtkImageViewer2.SetSlice(int), and found that method consumed large amounts of CPU usage, especailly when continually setting different slices. Is this a known issue…

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## [Multiple views of the same scene](https://discourse.vtk.org/t/multiple-views-of-the-same-scene/5045)

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**Author:** [@sheepy9](https://discourse.vtk.org/u/sheepy9)\
**Replies:** 2\
**Last updated:** [February 22, 2021, 1:35pm UTC](https://discourse.vtk.org/t/multiple-views-of-the-same-scene/5045 "2021-02-22T13:35:05Z")

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Hi, I’ve seen a similar question here, but the details are slightly different so I’d thought to ask again. So I need some way to visualise multiple views of the same scene, so I need to draw a different camera perspect…

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## [How can I solve the error, Cannot build Rendering examples without VTK\_SOURCE\_DIR](https://discourse.vtk.org/t/how-can-i-solve-the-error-cannot-build-rendering-examples-without-vtk-source-dir/5219)

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**Author:** [@xiaocaiji](https://discourse.vtk.org/u/xiaocaiji)\
**Replies:** 6\
**Last updated:** [February 21, 2021, 4:09pm UTC](https://discourse.vtk.org/t/how-can-i-solve-the-error-cannot-build-rendering-examples-without-vtk-source-dir/5219 "2021-02-21T16:09:59Z")

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I tried to build the example “Rendering” in VTK8.2.0, and then I get the error: In the CMakeLists, what I have seen is

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## [Change the radius of picked actor (vtkSphereSource)](https://discourse.vtk.org/t/change-the-radius-of-picked-actor-vtkspheresource/4838)

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**Author:** [@Travis](https://discourse.vtk.org/u/Travis)\
**Replies:** 3\
**Last updated:** [February 21, 2021, 1:59pm UTC](https://discourse.vtk.org/t/change-the-radius-of-picked-actor-vtkspheresource/4838 "2021-02-21T13:59:55Z")

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Hi, I’m following this example https://lorensen.github.io/VTKExamples/site/Python/Picking/HighlightPickedActor/ which shows how to change color of the picked actor which is a vtkSphereSource. However, how is it possib…

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## [Trouble installing VTK on ubuntu](https://discourse.vtk.org/t/trouble-installing-vtk-on-ubuntu/5148)

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**Author:** [@kland](https://discourse.vtk.org/u/kland)\
**Replies:** 1\
**Last updated:** [February 21, 2021, 1:43pm UTC](https://discourse.vtk.org/t/trouble-installing-vtk-on-ubuntu/5148 "2021-02-21T13:43:52Z")

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Hello, when I try to run “make install” for VTK I get the following error: \[ 53%\] Built target ImagingMath make\[2\]: \*\*\* No rule to make target ‘/usr/lib/x86\_64-linux-gnu/libGLX.so’, needed by ‘lib/libvtkglew-9.0.so.9.0…

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## [Can we create Unstructured grid with time series? How?](https://discourse.vtk.org/t/can-we-create-unstructured-grid-with-time-series-how/5114)

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**Author:** [@henry](https://discourse.vtk.org/u/henry)\
**Replies:** 1\
**Last updated:** [February 21, 2021, 1:32pm UTC](https://discourse.vtk.org/t/can-we-create-unstructured-grid-with-time-series-how/5114 "2021-02-21T13:32:52Z")

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I just started to use VTK, and I know that we can create vtk objects with times series by creating a series of files with specific naming rule (e.g. f0.vtu, f1.vtu, … f\*.vtu …). Can we create one vtk object with time se…

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## [How to convert a gray image to rgb image with a specified colormap?](https://discourse.vtk.org/t/how-to-convert-a-gray-image-to-rgb-image-with-a-specified-colormap/5088)

<div class="topic-metadata">

**Author:** [@zhang-qiang-github](https://discourse.vtk.org/u/zhang-qiang-github)\
**Replies:** 1\
**Last updated:** [February 21, 2021, 12:38pm UTC](https://discourse.vtk.org/t/how-to-convert-a-gray-image-to-rgb-image-with-a-specified-colormap/5088 "2021-02-21T12:38:09Z")

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I need to convert a gray image to rgb color image. And I find that vtkLookupTable is useful to convert gray image to colored image. But, how can I assign the colormap? In matlab, there are some available colormaps, such …

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## [\[VTK 9.0.0\] Rendering Issue (many artifacts) with Nouveau driver](https://discourse.vtk.org/t/vtk-9-0-0-rendering-issue-many-artifacts-with-nouveau-driver/5222)

<div class="topic-metadata">

**Author:** [@aangelos28](https://discourse.vtk.org/u/aangelos28)\
**Replies:** 7\
**Last updated:** [February 21, 2021, 5:00am UTC](https://discourse.vtk.org/t/vtk-9-0-0-rendering-issue-many-artifacts-with-nouveau-driver/5222 "2021-02-21T05:00:08Z")

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Hello, I compiled and ran the TriangleColoredPoints example (https://vtk.org/Wiki/VTK/Examples/Cxx/PolyData/TriangleColoredPoints) but no render window was displaying and I was getting the following warning: WARN| vtkIn…

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## [Reading MRI in python using VTK](https://discourse.vtk.org/t/reading-mri-in-python-using-vtk/5214)

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**Author:** [@Aya\_Hassan](https://discourse.vtk.org/u/Aya_Hassan)\
**Replies:** 0\
**Last updated:** [February 19, 2021, 6:50am UTC](https://discourse.vtk.org/t/reading-mri-in-python-using-vtk/5214 "2021-02-19T06:50:38Z")

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How can I read MRI images in python using VTK ?

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## [Transform Filter Applied to Unstructured Grid](https://discourse.vtk.org/t/transform-filter-applied-to-unstructured-grid/5203)

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**Author:** [@gsandh16](https://discourse.vtk.org/u/gsandh16)\
**Replies:** 3\
**Last updated:** [February 18, 2021, 8:03pm UTC](https://discourse.vtk.org/t/transform-filter-applied-to-unstructured-grid/5203 "2021-02-18T20:03:44Z")

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Hello, I am dealing with some issues related to applying a vtkTransformFilter() to a vtkUnstructuredGrid(). Namely, the unstructured grid does not have the same items before and after the application of the filter. Here…

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## [Use std::unique\_ptr with vtkObject instead of vtkSmartPointer](https://discourse.vtk.org/t/use-std-unique-ptr-with-vtkobject-instead-of-vtksmartpointer/5195)

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**Author:** [@boelraty](https://discourse.vtk.org/u/boelraty)\
**Replies:** 11\
**Last updated:** [February 17, 2021, 9:45pm UTC](https://discourse.vtk.org/t/use-std-unique-ptr-with-vtkobject-instead-of-vtksmartpointer/5195 "2021-02-17T21:45:18Z")

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Hi, Some people in my team would like to get rid of vtkSmartPointer and use the more classic std::unique\_ptr instead. My initial thought was : “Hell no !” but their implementation does not seem too bad. I’m wondering i…

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## [vtkBoxWidget change handles behavior](https://discourse.vtk.org/t/vtkboxwidget-change-handles-behavior/4344)

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**Author:** [@panicbuttonvfx](https://discourse.vtk.org/u/panicbuttonvfx)\
**Replies:** 3\
**Last updated:** [February 17, 2021, 2:30pm UTC](https://discourse.vtk.org/t/vtkboxwidget-change-handles-behavior/4344 "2021-02-17T14:30:12Z")

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Hi, Is it possible to change vtkBoxWidget handle’s behavior? I’d like to have the widget to either rotate or move locked on the axis of the handle I’m dragging (instead of resizing the box). Thanks!

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## [Transparent NaN scalars (vtk.js)](https://discourse.vtk.org/t/transparent-nan-scalars-vtk-js/5167)

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**Author:** [@Uros\_Stankovic](https://discourse.vtk.org/u/Uros_Stankovic)\
**Replies:** 4\
**Last updated:** [February 17, 2021, 1:39pm UTC](https://discourse.vtk.org/t/transparent-nan-scalars-vtk-js/5167 "2021-02-17T13:39:23Z")

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On the picture gray areas have NaN value, i need them to be transparent. I used lookupTable.setNanColor(1.0, 1.0, 1.0, 0), but alpha value doesn’t work. const lookupTable = vtkColorTransferFunction.newInstance(); c…

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## [Plane Fitting with vtk](https://discourse.vtk.org/t/plane-fitting-with-vtk/5196)

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**Author:** [@Seram](https://discourse.vtk.org/u/Seram)\
**Replies:** 7\
**Last updated:** [February 17, 2021, 12:23pm UTC](https://discourse.vtk.org/t/plane-fitting-with-vtk/5196 "2021-02-17T12:23:30Z")

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Hello I want to implement Plane Fitting using vtk. Can I get some information for your reference? I’m always getting your help. Thank you. BR

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## [Numpy tensor to vtkImageData](https://discourse.vtk.org/t/numpy-tensor-to-vtkimagedata/5154)

<div class="topic-metadata">

**Author:** [@rijobro](https://discourse.vtk.org/u/rijobro)\
**Replies:** 11\
**Last updated:** [February 16, 2021, 3:27pm UTC](https://discourse.vtk.org/t/numpy-tensor-to-vtkimagedata/5154 "2021-02-16T15:27:31Z")

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In python I’d like to use VTK to compute an inverse displacement field. The numpy array has shape, for example, \[100, 100, 1, 3\], the 3 being the tensor component. I want to copy this into a vtkImageData, and my current…

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## [Problem with vtkParallelRenderManger while using translucent cutplane](https://discourse.vtk.org/t/problem-with-vtkparallelrendermanger-while-using-translucent-cutplane/5198)

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**Author:** [@hari](https://discourse.vtk.org/u/hari)\
**Replies:** 0\
**Last updated:** [February 16, 2021, 7:07am UTC](https://discourse.vtk.org/t/problem-with-vtkparallelrendermanger-while-using-translucent-cutplane/5198 "2021-02-16T07:07:33Z")

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Hi All, I am quite new to vtk and I am trying to do a volume rendering of a vtkImageDataset in parallel using vtkcompositeendermanger. I am following these two examples \[1\] (https://gitlab.kitware.com/vtk/vtk/-/blob/fd…

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## [Cross Compiling VTK for Mobile Architectures](https://discourse.vtk.org/t/cross-compiling-vtk-for-mobile-architectures/5193)

<div class="topic-metadata">

**Author:** [@timt](https://discourse.vtk.org/u/timt)\
**Replies:** 6\
**Last updated:** [February 15, 2021, 9:11pm UTC](https://discourse.vtk.org/t/cross-compiling-vtk-for-mobile-architectures/5193 "2021-02-15T21:11:08Z")

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I am interested in consolidating our current functionality for cross-compiling VTK for mobile architectures (iOS, tvOS, Android, etc.). This is likely to have a lot of overlap with the new Apple M1 (arm64) chip support. …

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## [Non-Uniform Scale in vtk](https://discourse.vtk.org/t/non-uniform-scale-in-vtk/5190)

<div class="topic-metadata">

**Author:** [@zandarina](https://discourse.vtk.org/u/zandarina)\
**Replies:** 2\
**Last updated:** [February 15, 2021, 12:41pm UTC](https://discourse.vtk.org/t/non-uniform-scale-in-vtk/5190 "2021-02-15T12:41:24Z")

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Hello, I would like to know if vtk has a tool to apply a non-uniform scale. For example, I want to scale a polydata according to a vector but not symmetrically. Scale only allows positive vectors and different from 0. A…

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## [vtkOverlappingAMR + hidden cells](https://discourse.vtk.org/t/vtkoverlappingamr-hidden-cells/5192)

<div class="topic-metadata">

**Author:** [@hakostra](https://discourse.vtk.org/u/hakostra)\
**Replies:** 0\
**Last updated:** [February 15, 2021, 12:33pm UTC](https://discourse.vtk.org/t/vtkoverlappingamr-hidden-cells/5192 "2021-02-15T12:33:28Z")

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I use Python to assemble an vtkOverlappingAMR datastructure. The data I fill into it comes from a CFD code. This code use an immersed boundary method, so some gridcells are “blocked” - because no fluid is present there. …

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## [Minimum java version](https://discourse.vtk.org/t/minimum-java-version/5173)

<div class="topic-metadata">

**Author:** [@toddy](https://discourse.vtk.org/u/toddy)\
**Replies:** 9\
**Last updated:** [February 15, 2021, 5:47am UTC](https://discourse.vtk.org/t/minimum-java-version/5173 "2021-02-15T05:47:58Z")

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Does VTK require a minimum version of Java to compile its wrapper code?

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## [2D actor display problem](https://discourse.vtk.org/t/2d-actor-display-problem/5186)

<div class="topic-metadata">

**Author:** [@yuhuimoon](https://discourse.vtk.org/u/yuhuimoon)\
**Replies:** 0\
**Last updated:** [February 15, 2021, 2:41am UTC](https://discourse.vtk.org/t/2d-actor-display-problem/5186 "2021-02-15T02:41:30Z")

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Hi, everyone! I meet a problem about vtk 2D actor. I use vtkAxisActor2D as a axis in the axial view (x-y plane) and it can display facing the camera rightly. Now I want to show it in sagittal view(y-z plane) and coronal…

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## [Can I pick the point on pointcloud just like picture?](https://discourse.vtk.org/t/can-i-pick-the-point-on-pointcloud-just-like-picture/5172)

<div class="topic-metadata">

**Author:** [@timeanddoctor](https://discourse.vtk.org/u/timeanddoctor)\
**Replies:** 2\
**Last updated:** [February 15, 2021, 12:57am UTC](https://discourse.vtk.org/t/can-i-pick-the-point-on-pointcloud-just-like-picture/5172 "2021-02-15T00:57:18Z")

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def pick(obj,event): clickPos = obj.GetEventPosition() #print (clickPos) picker.Pick(clickPos\[0\], clickPos\[1\], 0, ren) p=picker.GetPickPosition() print ('position：',p)

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