# Latest

**URL:** https://discourse.vtk.org/latest.md?page=223

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

**Page:** 224

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## [libexpat 2.2.6 version presents some vulnerabilities](https://discourse.vtk.org/t/libexpat-2-2-6-version-presents-some-vulnerabilities/2697)

<div class="topic-metadata">

**Author:** [@simonesneault](https://discourse.vtk.org/u/simonesneault)\
**Replies:** 2\
**Last updated:** [February 28, 2020, 2:38pm UTC](https://discourse.vtk.org/t/libexpat-2-2-6-version-presents-some-vulnerabilities/2697 "2020-02-28T14:38:37Z")

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Hi All, The embedded version of libexpat (2.2.6) in VTK presents some vulnerabilities : https://nvd.nist.gov/vuln/detail/CVE-2019-15903 https://nvd.nist.gov/vuln/detail/CVE-2018-20843 Would it be possible to bump the…

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## [building libs for r/w vtk and xdmf geometry formats](https://discourse.vtk.org/t/building-libs-for-r-w-vtk-and-xdmf-geometry-formats/2724)

<div class="topic-metadata">

**Author:** [@kcris](https://discourse.vtk.org/u/kcris)\
**Replies:** 0\
**Last updated:** [February 28, 2020, 2:07pm UTC](https://discourse.vtk.org/t/building-libs-for-r-w-vtk-and-xdmf-geometry-formats/2724 "2020-02-28T14:07:53Z")

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Hi, I plan to use vtk libraries for reading/writing various vtk geometry objects (using vtk text formats, xdms formats). Vtk sourcecode is huge and I am a bit lost, there are literally hundreds of modules. And I am ju…

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## [How to reduce Moire pattern](https://discourse.vtk.org/t/how-to-reduce-moire-pattern/2716)

<div class="topic-metadata">

**Author:** [@yuhuimoon](https://discourse.vtk.org/u/yuhuimoon)\
**Replies:** 1\
**Last updated:** [February 28, 2020, 11:08am UTC](https://discourse.vtk.org/t/how-to-reduce-moire-pattern/2716 "2020-02-28T11:08:43Z")

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I use vtkTubeFilter to build some tube models in the scene. When the camera is far from the model, I can see the Moire pattern.(picture 1) The model is built correctly. When the camera is near to it, it renders well.(pic…

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## [Area widget](https://discourse.vtk.org/t/area-widget/2722)

<div class="topic-metadata">

**Author:** [@flaviu2](https://discourse.vtk.org/u/flaviu2)\
**Replies:** 0\
**Last updated:** [February 28, 2020, 11:03am UTC](https://discourse.vtk.org/t/area-widget/2722 "2020-02-28T11:03:49Z")

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Hello all of you. Is there a widget that is similar with distance and angle widget but who can measure area of a surface (rectangle, circle, etc.) ? I thought that border is my widget, but this border widget doesn’t fol…

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## [load C-Style Images without using vtkImageImport](https://discourse.vtk.org/t/load-c-style-images-without-using-vtkimageimport/2708)

<div class="topic-metadata">

**Author:** [@Yongun\_Lee](https://discourse.vtk.org/u/Yongun_Lee)\
**Replies:** 0\
**Last updated:** [February 27, 2020, 7:59am UTC](https://discourse.vtk.org/t/load-c-style-images-without-using-vtkimageimport/2708 "2020-02-27T07:59:55Z")

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Hello. I have a question. Is there a way to load \* C-Style Images \* without using vtkImageImport? Passing an image buffer using vtkImageImport will refresh the image buffer each time. Is there a way to add image slices …

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## [Using vtkImagePermute on vtkImageData with multiple scalars](https://discourse.vtk.org/t/using-vtkimagepermute-on-vtkimagedata-with-multiple-scalars/2714)

<div class="topic-metadata">

**Author:** [@Patrick\_Avery](https://discourse.vtk.org/u/Patrick_Avery)\
**Replies:** 3\
**Last updated:** [February 28, 2020, 12:34am UTC](https://discourse.vtk.org/t/using-vtkimagepermute-on-vtkimagedata-with-multiple-scalars/2714 "2020-02-28T00:34:32Z")

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We have been using vtkImagePermute to swap two axes on vtkImageData in Tomviz. We have also recently been adding support for the vtkImageData to have multiple scalars associated with it (i. e., image-\>GetPointData()-\>Get…

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## [vtkGL2PSExporter end line trouble](https://discourse.vtk.org/t/vtkgl2psexporter-end-line-trouble/2711)

<div class="topic-metadata">

**Author:** [@Nicolas\_Lenoir](https://discourse.vtk.org/u/Nicolas_Lenoir)\
**Replies:** 3\
**Last updated:** [February 27, 2020, 4:56pm UTC](https://discourse.vtk.org/t/vtkgl2psexporter-end-line-trouble/2711 "2020-02-27T16:56:34Z")

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Hello, I post this topic because I have a problem when I export a render window conatining vtkCaptionActor in PDF or SVG file by using vtkGL2PSExporter. When this object is export the containing text appear without end l…

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## [Creating a MR requires to be a VTK "Developer"](https://discourse.vtk.org/t/creating-a-mr-requires-to-be-a-vtk-developer/2705)

<div class="topic-metadata">

**Author:** [@mwestphal](https://discourse.vtk.org/u/mwestphal)\
**Replies:** 3\
**Last updated:** [February 27, 2020, 7:50am UTC](https://discourse.vtk.org/t/creating-a-mr-requires-to-be-a-vtk-developer/2705 "2020-02-27T07:50:08Z")

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It looks like it is required to be part of the VTK group at developer level to be able to create a MR. Is that intended ? The develop.md does not mention it at all. @utkarshayachit @brad.king @cory.quammen

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## [Calling SetSize(X, Y) or Getsize() on a vtkRenderWindow has some undefined behaviors](https://discourse.vtk.org/t/calling-setsize-x-y-or-getsize-on-a-vtkrenderwindow-has-some-undefined-behaviors/2703)

<div class="topic-metadata">

**Author:** [@jjackso2](https://discourse.vtk.org/u/jjackso2)\
**Replies:** 0\
**Last updated:** [February 26, 2020, 10:22pm UTC](https://discourse.vtk.org/t/calling-setsize-x-y-or-getsize-on-a-vtkrenderwindow-has-some-undefined-behaviors/2703 "2020-02-26T22:22:13Z")

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Title. This will result in GetSize() returning values different from X and Y in SetSize(X, Y) called prior. Most often than not, if you try calling SetSize() multiple times with the same values it will end up working …

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## [Rendering problems with per-cell colored surfaces on Surface 7](https://discourse.vtk.org/t/rendering-problems-with-per-cell-colored-surfaces-on-surface-7/2698)

<div class="topic-metadata">

**Author:** [@nenad-vujicic](https://discourse.vtk.org/u/nenad-vujicic)\
**Replies:** 7\
**Last updated:** [February 26, 2020, 2:33pm UTC](https://discourse.vtk.org/t/rendering-problems-with-per-cell-colored-surfaces-on-surface-7/2698 "2020-02-26T14:33:25Z")

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Hello everyone, I’m having problems with using my VTK + QT application and per-cell coloring on Surface 7 tablet. I use VTK version (a5f938b2fdfefa522439065e040cb42f65d88444) which was used btw for the latest ParaView r…

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## [Updating vtkPointInterpolator](https://discourse.vtk.org/t/updating-vtkpointinterpolator/2657)

<div class="topic-metadata">

**Author:** [@michael23](https://discourse.vtk.org/u/michael23)\
**Replies:** 1\
**Last updated:** [February 26, 2020, 12:13pm UTC](https://discourse.vtk.org/t/updating-vtkpointinterpolator/2657 "2020-02-26T12:13:46Z")

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Hi, I am using the vtkPointInterpolator to interpolate the scalars of some points onto a surface. vtkSmartPointer\<vtkDoubleArray\> scalars = vtkSmartPointer\<vtkDoubleArray\>::New(); scalars-\>SetName("sca"); scalars-\>SetN…

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## [Render 3D objects to constant size in 2D.](https://discourse.vtk.org/t/render-3d-objects-to-constant-size-in-2d/2660)

<div class="topic-metadata">

**Author:** [@aries24](https://discourse.vtk.org/u/aries24)\
**Replies:** 4\
**Last updated:** [February 26, 2020, 12:00pm UTC](https://discourse.vtk.org/t/render-3d-objects-to-constant-size-in-2d/2660 "2020-02-26T12:00:22Z")

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We are creating an application using VTK to visualize a network of nodes and connecting edges in 3D. In a previous version of this application, visualization was solely done in 2D. Since these networks may have large va…

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## [How to check if a line intersects with (triangular) cell?](https://discourse.vtk.org/t/how-to-check-if-a-line-intersects-with-triangular-cell/2672)

<div class="topic-metadata">

**Author:** [@normanius](https://discourse.vtk.org/u/normanius)\
**Replies:** 6\
**Last updated:** [February 26, 2020, 10:39am UTC](https://discourse.vtk.org/t/how-to-check-if-a-line-intersects-with-triangular-cell/2672 "2020-02-26T10:39:52Z")

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Dear all I would like to test if a line intersects with a triangle. If the line is not lying in the same plane as triangle this is done easily with vtkTriangle.IntersectWithLine(). But how can I detect a collision if t…

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## [How do I build special lattice model with implicit modeling?](https://discourse.vtk.org/t/how-do-i-build-special-lattice-model-with-implicit-modeling/2651)

<div class="topic-metadata">

**Author:** [@Puth\_Charlie](https://discourse.vtk.org/u/Puth_Charlie)\
**Replies:** 2\
**Last updated:** [February 26, 2020, 4:17am UTC](https://discourse.vtk.org/t/how-do-i-build-special-lattice-model-with-implicit-modeling/2651 "2020-02-26T04:17:47Z")

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In VTK, is there any way to generate a lattice model similar to the one shown below by either implicit modeling or Level-set? If I switch to a lattice model like the one below, how do I build with implicit modeling?

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## [How to decimate a 3D box mesh generated by GMSH?](https://discourse.vtk.org/t/how-to-decimate-a-3d-box-mesh-generated-by-gmsh/2699)

<div class="topic-metadata">

**Author:** [@duy\_duc](https://discourse.vtk.org/u/duy_duc)\
**Replies:** 3\
**Last updated:** [February 25, 2020, 8:24pm UTC](https://discourse.vtk.org/t/how-to-decimate-a-3d-box-mesh-generated-by-gmsh/2699 "2020-02-25T20:24:04Z")

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Hi everyone I am new to VTK. I want to decimate a box meshed with tetrahedra and generated by GMSH. I follow the example for Python here. However, my decimated mesh only contain boundaries of the box and 2D triangle m…

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## [VTK 9.0](https://discourse.vtk.org/t/vtk-9-0/2691)

<div class="topic-metadata">

**Author:** [@TJ\_Corona](https://discourse.vtk.org/u/TJ_Corona)\
**Replies:** 3\
**Last updated:** [February 25, 2020, 2:57pm UTC](https://discourse.vtk.org/t/vtk-9-0/2691 "2020-02-25T14:57:43Z")

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Hi, Does anyone have work in progress that should delay the branch point for v9.0.0? If so, please add the v9.0.0\_rc1 milestone on any relevant merge requests and mention @ben.boeckel @TJ\_Corona so they can be more e…

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## [Fill area between lines with different colors](https://discourse.vtk.org/t/fill-area-between-lines-with-different-colors/2681)

<div class="topic-metadata">

**Author:** [@kerim](https://discourse.vtk.org/u/kerim)\
**Replies:** 1\
**Last updated:** [February 24, 2020, 7:25pm UTC](https://discourse.vtk.org/t/fill-area-between-lines-with-different-colors/2681 "2020-02-24T19:25:09Z")

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Hi, Is there a way to plot line that has three dimensions (x, y, z) on two dimensional XY axes and fill the area between this line and some baseline (usually baseline is a constant value line) with color coded by z-valu…

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## [strange problems when running the examples in different languages](https://discourse.vtk.org/t/strange-problems-when-running-the-examples-in-different-languages/2571)

<div class="topic-metadata">

**Author:** [@chaos](https://discourse.vtk.org/u/chaos)\
**Replies:** 7\
**Last updated:** [February 24, 2020, 2:12pm UTC](https://discourse.vtk.org/t/strange-problems-when-running-the-examples-in-different-languages/2571 "2020-02-24T14:12:13Z")

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Hi, I’m a VTK beginner, and I have a strange problem when I ran the VTK example, which was that setting the renderer’s background color would sometimes fail and the background would turn black, and dragging the actor ins…

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## [How to create a rectilinear grid by vtk.js?](https://discourse.vtk.org/t/how-to-create-a-rectilinear-grid-by-vtk-js/2687)

<div class="topic-metadata">

**Author:** [@Yue\_JIN](https://discourse.vtk.org/u/Yue_JIN)\
**Replies:** 1\
**Last updated:** [February 24, 2020, 7:53am UTC](https://discourse.vtk.org/t/how-to-create-a-rectilinear-grid-by-vtk-js/2687 "2020-02-24T07:53:05Z")

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Is it possible to create a rectilinear/structured grid from scratch by vtk.js? In C++, we can use vtkRectilinearGrid. But in official website, I haven’t found any related example.

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## [vtkWebViewPort: vtkOpenGLCamera has no attribute 'ResetCamera'](https://discourse.vtk.org/t/vtkwebviewport-vtkopenglcamera-has-no-attribute-resetcamera/2654)

<div class="topic-metadata">

**Author:** [@BotellaA](https://discourse.vtk.org/u/BotellaA)\
**Replies:** 1\
**Last updated:** [February 23, 2020, 8:10pm UTC](https://discourse.vtk.org/t/vtkwebviewport-vtkopenglcamera-has-no-attribute-resetcamera/2654 "2020-02-23T20:10:13Z")

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I am using the vkWebViewPort and the rpc "viewport.camera.reset" . Here is the error I get: "AttributeError("'vtkmodules.vtkRenderingOpenGL2.vtkOpenGLCamera' object has no attribute 'ResetCamera'",)" I cannot find how t…

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## [VTK (pyqt): from world coordinate to display coordinate](https://discourse.vtk.org/t/vtk-pyqt-from-world-coordinate-to-display-coordinate/2626)

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**Author:** [@zhang-qiang-github](https://discourse.vtk.org/u/zhang-qiang-github)\
**Replies:** 14\
**Last updated:** [February 23, 2020, 3:07am UTC](https://discourse.vtk.org/t/vtk-pyqt-from-world-coordinate-to-display-coordinate/2626 "2020-02-23T03:07:22Z")

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I am using VTK for my project. Now, I need to convert the point from world coordinate to display coordinate, and the result is wrong. The following pyqt code is used to reproduce the problem I meet. from PyQt5.QtWidgets…

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## [copy data from Armadillo matrix to vtkFloatArray](https://discourse.vtk.org/t/copy-data-from-armadillo-matrix-to-vtkfloatarray/2677)

<div class="topic-metadata">

**Author:** [@kerim](https://discourse.vtk.org/u/kerim)\
**Replies:** 4\
**Last updated:** [February 22, 2020, 11:23pm UTC](https://discourse.vtk.org/t/copy-data-from-armadillo-matrix-to-vtkfloatarray/2677 "2020-02-22T23:23:02Z")

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Hi, I use armadillo as math library and I would like to use VTK library to plot data. Is there a way to prepare data for plotting like: fvec(100) DATA; // armadillo vector of type float DATA.ones(100); // sets all 1…

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## [vtkDijkstraGraphGeodesicPath scalar weight question](https://discourse.vtk.org/t/vtkdijkstragraphgeodesicpath-scalar-weight-question/2663)

<div class="topic-metadata">

**Author:** [@Sunderlandkyl](https://discourse.vtk.org/u/Sunderlandkyl)\
**Replies:** 1\
**Last updated:** [February 22, 2020, 4:17pm UTC](https://discourse.vtk.org/t/vtkdijkstragraphgeodesicpath-scalar-weight-question/2663 "2020-02-22T16:17:44Z")

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When UseScalarWeights is enabled, the cost is calculated by dividing the distance by the squared scalar weight: https://gitlab.kitware.com/vtk/vtk/blob/master/Filters/Modeling/vtkDijkstraGraphGeodesicPath.cxx#L165-169 …

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## [VTK 8.2 + EGL offscreen rendering, nvidia driver 440.33.01](https://discourse.vtk.org/t/vtk-8-2-egl-offscreen-rendering-nvidia-driver-440-33-01/2607)

<div class="topic-metadata">

**Author:** [@Sophonet](https://discourse.vtk.org/u/Sophonet)\
**Replies:** 4\
**Last updated:** [February 22, 2020, 1:31pm UTC](https://discourse.vtk.org/t/vtk-8-2-egl-offscreen-rendering-nvidia-driver-440-33-01/2607 "2020-02-22T13:31:13Z")

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Hi there, I am interested in EGL-accelerated offscreen rendering and have read https://blog.kitware.com/off-screen-rendering-through-the-native-platform-interface-egl/. I have successfully built VTK 8.2.0 with using GC…

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## [Plot disappearing](https://discourse.vtk.org/t/plot-disappearing/2676)

<div class="topic-metadata">

**Author:** [@snip777](https://discourse.vtk.org/u/snip777)\
**Replies:** 0\
**Last updated:** [February 21, 2020, 8:52pm UTC](https://discourse.vtk.org/t/plot-disappearing/2676 "2020-02-21T20:52:33Z")

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I wrote custom plot which derives from vtkPlot and added it to vtkChartXY. When i zoomin at some point the plot just disappears. I looked at vtk sources and found that the problem originates in function vtkChart::Calcu…

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## [Best way to overlay multiple 2D images?](https://discourse.vtk.org/t/best-way-to-overlay-multiple-2d-images/2671)

<div class="topic-metadata">

**Author:** [@msmerps](https://discourse.vtk.org/u/msmerps)\
**Replies:** 2\
**Last updated:** [February 21, 2020, 5:22pm UTC](https://discourse.vtk.org/t/best-way-to-overlay-multiple-2d-images/2671 "2020-02-21T17:22:27Z")

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Hi, I’m interested in making overlays of two or more 2D images in VTK (e.g., two MRIs taken multiple years apart). There appear to be two ways of doing this in VTK: via vtkImageBlend (https://itk.org/Wiki/VTK/Examples/…

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## [vtkTextWidget position is not updated when the camera or zoom is used](https://discourse.vtk.org/t/vtktextwidget-position-is-not-updated-when-the-camera-or-zoom-is-used/2604)

<div class="topic-metadata">

**Author:** [@zandarina](https://discourse.vtk.org/u/zandarina)\
**Replies:** 2\
**Last updated:** [February 21, 2020, 4:37pm UTC](https://discourse.vtk.org/t/vtktextwidget-position-is-not-updated-when-the-camera-or-zoom-is-used/2604 "2020-02-21T16:37:32Z")

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Dear all, I am trying to put a text around a object all in 2d. But i found that this widget when i move the camera (or zoom in an area) the objects moves correctly but the text widget stays and is not accordingly update…

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## [explain the vtk architecture design](https://discourse.vtk.org/t/explain-the-vtk-architecture-design/1978)

<div class="topic-metadata">

**Author:** [@kayarre](https://discourse.vtk.org/u/kayarre)\
**Replies:** 21\
**Last updated:** [February 21, 2020, 4:08pm UTC](https://discourse.vtk.org/t/explain-the-vtk-architecture-design/1978 "2020-02-21T16:08:41Z")

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Hi, I have been using VTK for over 5 years now and the various projects derived from it vmtk, paraview, 3Dslicer, etc. generally using the python bindings when developing scripts and such. I am now developing in c++ an…

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## [Sensible default for covalent radius](https://discourse.vtk.org/t/sensible-default-for-covalent-radius/2648)

<div class="topic-metadata">

**Author:** [@Jellby](https://discourse.vtk.org/u/Jellby)\
**Replies:** 3\
**Last updated:** [February 21, 2020, 10:58am UTC](https://discourse.vtk.org/t/sensible-default-for-covalent-radius/2648 "2020-02-21T10:58:44Z")

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I’m using vtkMolecule and vtkSimpleBondPerceiver to display reasonable structures for molecules. But there is a problem when a particular atom does not have a covalent radius specified in the default database: the radius…

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## [Get a vector at specific voxel coordinates](https://discourse.vtk.org/t/get-a-vector-at-specific-voxel-coordinates/2664)

<div class="topic-metadata">

**Author:** [@Nina](https://discourse.vtk.org/u/Nina)\
**Replies:** 0\
**Last updated:** [February 20, 2020, 6:20pm UTC](https://discourse.vtk.org/t/get-a-vector-at-specific-voxel-coordinates/2664 "2020-02-20T18:20:20Z")

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Hi, I have applied a 3d sobel filter on vtkImageData like this: vtkSmartPointer\<vtkImageSobel3D\> sobelFilter = vtkSmartPointer\<vtkImageSobel3D\>::New(); sobelFilter-\>SetInputData(image); sobelFilter-\>Update(); My quest…

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