# Support

**URL:** https://discourse.vtk.org/c/support/6.md?page=132

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

**Page:** 133

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## [Building Python 3 support when building from source](https://discourse.vtk.org/t/building-python-3-support-when-building-from-source/3236)

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**Author:** [@mshaikh786](https://discourse.vtk.org/u/mshaikh786)\
**Replies:** 2\
**Last updated:** [May 7, 2020, 3:35pm UTC](https://discourse.vtk.org/t/building-python-3-support-when-building-from-source/3236 "2020-05-07T15:35:29Z")

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Hi, I am building VTK 9.0.0 stable release. How do I direct CMake to build Python3 binding? By default it is building python2.7 bindings.

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## [Building VTK 9.0 fails when using mpi support](https://discourse.vtk.org/t/building-vtk-9-0-fails-when-using-mpi-support/3227)

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**Author:** [@badshah400](https://discourse.vtk.org/u/badshah400)\
**Replies:** 7\
**Last updated:** [May 7, 2020, 1:32am UTC](https://discourse.vtk.org/t/building-vtk-9-0-fails-when-using-mpi-support/3227 "2020-05-07T01:32:10Z")

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When building VTK 9.0 with mpi support, the build fails at linking to generate vtkFiltersParallelGeometryJava with the following errors. Building works without any issue when not compiling with mpi support, which leads m…

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## [Query fraction of rendered pixels](https://discourse.vtk.org/t/query-fraction-of-rendered-pixels/3228)

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**Author:** [@woodscn](https://discourse.vtk.org/u/woodscn)\
**Replies:** 0\
**Last updated:** [May 6, 2020, 6:51pm UTC](https://discourse.vtk.org/t/query-fraction-of-rendered-pixels/3228 "2020-05-06T18:51:26Z")

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I’m fairly new to VTK, so I apologize if this is already answered somewhere. I’m rendering a large point cloud, and I quickly saturate the screen as the data size increases. I’d like to algorithmically describe this sat…

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## [\[VTK 9.0.0rc3\] Python can't set multisamples](https://discourse.vtk.org/t/vtk-9-0-0rc3-python-cant-set-multisamples/3223)

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**Author:** [@jasonb5](https://discourse.vtk.org/u/jasonb5)\
**Replies:** 0\
**Last updated:** [May 6, 2020, 2:32am UTC](https://discourse.vtk.org/t/vtk-9-0-0rc3-python-cant-set-multisamples/3223 "2020-05-06T02:32:20Z")

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Calling SetMultiSamples has no affect using VTK 9.0.0rc3. In both examples I would expect the output to show a difference in images but only the 8.2.0 environment produces these results. I’m unsure if i’m using this corr…

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## [vtkClipVolume using an implicit function (vtkCylinder) - errors on output grid](https://discourse.vtk.org/t/vtkclipvolume-using-an-implicit-function-vtkcylinder-errors-on-output-grid/3198)

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**Author:** [@vitorvas](https://discourse.vtk.org/u/vitorvas)\
**Replies:** 2\
**Last updated:** [May 6, 2020, 2:43pm UTC](https://discourse.vtk.org/t/vtkclipvolume-using-an-implicit-function-vtkcylinder-errors-on-output-grid/3198 "2020-05-06T14:43:30Z")

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Hello! I’m clipping a vtkUnstructuredGrid with a vtkCylinder. I got both parts (making use of GenerateClippedOutputOn()). However, one of my resultant grid has artifacts. I wasn’t able to be sure what are the problem, …

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## [Appending data field to a vtk file (Python VTK)](https://discourse.vtk.org/t/appending-data-field-to-a-vtk-file-python-vtk/3220)

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**Author:** [@Shahid](https://discourse.vtk.org/u/Shahid)\
**Replies:** 5\
**Last updated:** [May 6, 2020, 10:02am UTC](https://discourse.vtk.org/t/appending-data-field-to-a-vtk-file-python-vtk/3220 "2020-05-06T10:02:54Z")

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Hi I have an array which I wish to add as another data field to an existing vtk file - but im struggling to get it to work. I’m using python, specificaly the build of python and vtk that comes with paraview 5.6.This is …

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## [MPR with vtk-dicom](https://discourse.vtk.org/t/mpr-with-vtk-dicom/3224)

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**Author:** [@Yongun\_Lee](https://discourse.vtk.org/u/Yongun_Lee)\
**Replies:** 0\
**Last updated:** [May 6, 2020, 4:46am UTC](https://discourse.vtk.org/t/mpr-with-vtk-dicom/3224 "2020-05-06T04:46:23Z")

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Hi. I used d.gobbi’s vtk-dicom and the MPR is showing abnormally. (Annotated Cube faces the Anterior, but the volume faces the person’s right face.) I loaded one series from vtkDICOMReader and applied the coordinate sy…

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## [How to make a DicomImage fill a window](https://discourse.vtk.org/t/how-to-make-a-dicomimage-fill-a-window/3218)

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**Author:** [@Amnesie](https://discourse.vtk.org/u/Amnesie)\
**Replies:** 2\
**Last updated:** [May 6, 2020, 2:05am UTC](https://discourse.vtk.org/t/how-to-make-a-dicomimage-fill-a-window/3218 "2020-05-06T02:05:35Z")

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Here is my code , vtkSmartPointer imageViewer =vtkSmartPointer::New(); imageViewer-\>SetInputConnection(imageflip-\>GetOutputPort()); imageViewer-\>Render(); imageViewer-\>GetRenderWindow()-\>SetWindowName(“ROI”); imag…

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## [Deleting points from vtkPolyData](https://discourse.vtk.org/t/deleting-points-from-vtkpolydata/3222)

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**Author:** [@MMoussa](https://discourse.vtk.org/u/MMoussa)\
**Replies:** 0\
**Last updated:** [May 6, 2020, 12:25am UTC](https://discourse.vtk.org/t/deleting-points-from-vtkpolydata/3222 "2020-05-06T00:25:30Z")

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Brand new to VTK I am using the C# wrapper (Activiz) to build an interactive application. I’m trying to figure out how to delete points from vtkPolyData (more generally, how to efficiently use this data structure in an …

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## [How to compute surface- and volume-based center of masses for 3D geometries](https://discourse.vtk.org/t/how-to-compute-surface-and-volume-based-center-of-masses-for-3d-geometries/3215)

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**Author:** [@normanius](https://discourse.vtk.org/u/normanius)\
**Replies:** 3\
**Last updated:** [May 5, 2020, 11:05pm UTC](https://discourse.vtk.org/t/how-to-compute-surface-and-volume-based-center-of-masses-for-3d-geometries/3215 "2020-05-05T23:05:04Z")

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Hello For (closed) 3D surface geometries with triangular mesh, I can think of three different types to compute the “center of mass”: point-based: center=sum(points)/len(points) surface-based: center=sum(tri\_areas\*tri…

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## [Vtk threshold not passing cell and point data](https://discourse.vtk.org/t/vtk-threshold-not-passing-cell-and-point-data/3188)

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**Author:** [@a-jp1](https://discourse.vtk.org/u/a-jp1)\
**Replies:** 1\
**Last updated:** [May 5, 2020, 9:40pm UTC](https://discourse.vtk.org/t/vtk-threshold-not-passing-cell-and-point-data/3188 "2020-05-05T21:40:01Z")

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Hi, I’m sure I’ve done this before in c++ with vtk. Have a vtkunstructuredgrid that I threshold on a cell based int array. There is other cell and point data on the mesh but it’s not being passed. If I do the same opt…

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## [Marking algorithm output as unchanged](https://discourse.vtk.org/t/marking-algorithm-output-as-unchanged/3210)

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**Author:** [@BetaRavener](https://discourse.vtk.org/u/BetaRavener)\
**Replies:** 0\
**Last updated:** [May 5, 2020, 9:59am UTC](https://discourse.vtk.org/t/marking-algorithm-output-as-unchanged/3210 "2020-05-05T09:59:28Z")

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Hi. I have a situation in which I have a two filters and a time-aware source. Source (A) is connected to first filter (B), which filters the data based on some criteria. Output of B is connected to computationally heavy …

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## [How to implement a vtkImageData with boolean data?](https://discourse.vtk.org/t/how-to-implement-a-vtkimagedata-with-boolean-data/3209)

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**Author:** [@MichelleKline](https://discourse.vtk.org/u/MichelleKline)\
**Replies:** 2\
**Last updated:** [May 5, 2020, 12:00am UTC](https://discourse.vtk.org/t/how-to-implement-a-vtkimagedata-with-boolean-data/3209 "2020-05-05T00:00:17Z")

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Hello, Is it possible to create a vtkImageData with boolean data? For example: myImage = vtkSmartPointer\<vtkImageData\>::New(); myImage-\>AllocateScalars(VTK\_FLOAT, 1); // is boolean possible? Thank you, Michelle

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## [VolumeRendering Window Width and Window Level using VTK](https://discourse.vtk.org/t/volumerendering-window-width-and-window-level-using-vtk/3200)

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**Author:** [@watson](https://discourse.vtk.org/u/watson)\
**Replies:** 1\
**Last updated:** [May 4, 2020, 11:40pm UTC](https://discourse.vtk.org/t/volumerendering-window-width-and-window-level-using-vtk/3200 "2020-05-04T23:40:18Z")

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I need to change the Window Width and Window Level of the volume rendered image with mouse using vtk . I referred this link https://vtk.org/pipermail/vtkusers/2015-September/092338.html .But it has no precise answer. H…

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## [Does Slicer Allow Us to Export a Single Slice?](https://discourse.vtk.org/t/does-slicer-allow-us-to-export-a-single-slice/3158)

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**Author:** [@MichelleKline](https://discourse.vtk.org/u/MichelleKline)\
**Replies:** 3\
**Last updated:** [May 4, 2020, 11:08pm UTC](https://discourse.vtk.org/t/does-slicer-allow-us-to-export-a-single-slice/3158 "2020-05-04T23:08:37Z")

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Hello, Is there a way in Slicer to export the currently displayed (and likely reformatted) slice of a volume to an output file? For example, I have loaded a double-oblique DICOM, and I am viewing the volume in an axial…

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## [Problem with ambient and specular color in vtkLight using vtk 8.2.0](https://discourse.vtk.org/t/problem-with-ambient-and-specular-color-in-vtklight-using-vtk-8-2-0/2566)

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**Author:** [@santichialvo](https://discourse.vtk.org/u/santichialvo)\
**Replies:** 6\
**Last updated:** [May 4, 2020, 3:09pm UTC](https://discourse.vtk.org/t/problem-with-ambient-and-specular-color-in-vtklight-using-vtk-8-2-0/2566 "2020-05-04T15:09:11Z")

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Hi all, I recently migrated from VTK 6.3 to 8.2. I use two lights on the scene, and I have a small UI option to change the value of the components of the light. For this purpose, I use SetXXXColor() method. It’s strange…

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## [Manipulate data from a vtkXMLUnstructuredGridReader](https://discourse.vtk.org/t/manipulate-data-from-a-vtkxmlunstructuredgridreader/3179)

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**Author:** [@armel.demontgros](https://discourse.vtk.org/u/armel.demontgros)\
**Replies:** 6\
**Last updated:** [May 3, 2020, 9:36pm UTC](https://discourse.vtk.org/t/manipulate-data-from-a-vtkxmlunstructuredgridreader/3179 "2020-05-03T21:36:28Z")

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Hi, I am wondering what is the best way to manipulate the data coming from a vtkXMLUnstructuredGridReader. std::string filename = “C:\\VTK\\exm.vtu”; vtkNew reader; reader-\>SetFileName(filename.c\_str()); reader-\>Updat…

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## [vtkCamera - What coordinate system for setting variables?](https://discourse.vtk.org/t/vtkcamera-what-coordinate-system-for-setting-variables/3173)

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**Author:** [@tchen87](https://discourse.vtk.org/u/tchen87)\
**Replies:** 1\
**Last updated:** [May 1, 2020, 12:29pm UTC](https://discourse.vtk.org/t/vtkcamera-what-coordinate-system-for-setting-variables/3173 "2020-05-01T12:29:42Z")

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I’m attempting to use vtkCamera for my stereo rendering application, with OffAxisProjection. The display I’m using is tilted at an angle, so I wanted to get clarity on the proper coordinate system to use for the various …

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## [is there any way to check mesh is watertight?](https://discourse.vtk.org/t/is-there-any-way-to-check-mesh-is-watertight/3169)

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**Author:** [@srbn.ghosh99](https://discourse.vtk.org/u/srbn.ghosh99)\
**Replies:** 3\
**Last updated:** [April 30, 2020, 10:02pm UTC](https://discourse.vtk.org/t/is-there-any-way-to-check-mesh-is-watertight/3169 "2020-04-30T22:02:27Z")

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Hi, I have used PolyDataConnectivityFilter to get rid of disconnected vertices. Is that enough to check if the mesh is watertight? Or I need to use any other filter to check if the mesh is watertight? Could you sugges…

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## [vtkScalarBarActor](https://discourse.vtk.org/t/vtkscalarbaractor/3186)

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**Author:** [@VannieZ](https://discourse.vtk.org/u/VannieZ)\
**Replies:** 0\
**Last updated:** [April 30, 2020, 6:07pm UTC](https://discourse.vtk.org/t/vtkscalarbaractor/3186 "2020-04-30T18:07:48Z")

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Hello, I am using ActiViz Edition 5.8.0 I am trying to set colorbar values which are always between \[0,1\] (it would be okay, plot looks perfect with many colors on it, but for my subject it is very important to have co…

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## [vtkimageViewer2 can't Render the DicomSeries](https://discourse.vtk.org/t/vtkimageviewer2-cant-render-the-dicomseries/3171)

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**Author:** [@Amnesie](https://discourse.vtk.org/u/Amnesie)\
**Replies:** 3\
**Last updated:** [April 30, 2020, 5:00pm UTC](https://discourse.vtk.org/t/vtkimageviewer2-cant-render-the-dicomseries/3171 "2020-04-30T17:00:43Z")

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Hello everyone , I used ITK to create a Dicomseries from a Raw Volumen pure .raw data not include mhd or any header i just add some tags by manual ,so the Dicomseries dont have much Dicom-Tags. Then i try to render the…

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## [AVIWriter on Ubuntu](https://discourse.vtk.org/t/aviwriter-on-ubuntu/3183)

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**Author:** [@FabianSchuetze](https://discourse.vtk.org/u/FabianSchuetze)\
**Replies:** 1\
**Last updated:** [April 30, 2020, 2:51pm UTC](https://discourse.vtk.org/t/aviwriter-on-ubuntu/3183 "2020-04-30T14:51:38Z")

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I would like to use the VTKAVIWriter.h on Ubuntu but do unfortunately not know how to do that. I indeed find the header in the source files but its not among the installed files after compilation. I looked for compile …

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## [Compile Error: Definition Provided for Explicit instantiation](https://discourse.vtk.org/t/compile-error-definition-provided-for-explicit-instantiation/3176)

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**Author:** [@FabianSchuetze](https://discourse.vtk.org/u/FabianSchuetze)\
**Replies:** 5\
**Last updated:** [April 30, 2020, 8:58am UTC](https://discourse.vtk.org/t/compile-error-definition-provided-for-explicit-instantiation/3176 "2020-04-30T08:58:21Z")

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When compiling software that includes vtkFloatArray.h with Qtcreator and gcc 9.3 as compiler on Ubuntu 20.04 I receive the following error: /usr/local/include/vtk-8.2/vtkFloatArray.h:38:3: error: definition provided for…

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## [Write scene from Vtk PolyData to PNG File](https://discourse.vtk.org/t/write-scene-from-vtk-polydata-to-png-file/3057)

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**Author:** [@goflo](https://discourse.vtk.org/u/goflo)\
**Replies:** 4\
**Last updated:** [April 30, 2020, 7:42am UTC](https://discourse.vtk.org/t/write-scene-from-vtk-polydata-to-png-file/3057 "2020-04-30T07:42:00Z")

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Hi, I have VTK PolyData XML files which are generated by a .NET Core Webservice. I’m building now an other .NET Service which will generate PDF reports. Part of this reports are a few images from the 3D model. I need to…

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## [INTERPOLATE ON STL: Plotting scalar field on 50 points on An 70000-points STL surface](https://discourse.vtk.org/t/interpolate-on-stl-plotting-scalar-field-on-50-points-on-an-70000-points-stl-surface/450)

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**Author:** [@Hosam](https://discourse.vtk.org/u/Hosam)\
**Replies:** 18\
**Last updated:** [April 29, 2020, 1:26am UTC](https://discourse.vtk.org/t/interpolate-on-stl-plotting-scalar-field-on-50-points-on-an-70000-points-stl-surface/450 "2020-04-29T01:26:46Z")

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Hello, I have an STL surface file. The data were sampled on 50 selected points only (wind tunnel test). I want to visualize the field as a contour on the STL file. I know basic stuff on how to use VTK python library.…

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## [How to have multiple polylines in polydata?](https://discourse.vtk.org/t/how-to-have-multiple-polylines-in-polydata/3170)

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**Author:** [@dzenanz](https://discourse.vtk.org/u/dzenanz)\
**Replies:** 7\
**Last updated:** [April 28, 2020, 5:57pm UTC](https://discourse.vtk.org/t/how-to-have-multiple-polylines-in-polydata/3170 "2020-04-28T17:57:06Z")

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I am starting from this example and I want to extend it to put multiple lines in a single polydata. My attempt is below. It results in an empty render window, whereas I expect some lines to be visible. What am I doing wr…

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## [Any guides for building VTK on Ubuntu 18.04 using WSL?](https://discourse.vtk.org/t/any-guides-for-building-vtk-on-ubuntu-18-04-using-wsl/2999)

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**Author:** [@Ahmed\_Salih](https://discourse.vtk.org/u/Ahmed_Salih)\
**Replies:** 14\
**Last updated:** [April 28, 2020, 1:58pm UTC](https://discourse.vtk.org/t/any-guides-for-building-vtk-on-ubuntu-18-04-using-wsl/2999 "2020-04-28T13:58:19Z")

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Hello! I am trying to build VTK 8.1 for Linux basically in WSL, because I want to incorporate this functionality showcasen here in my own code; https://lorensen.github.io/VTKExamples/site/Cxx/IO/WriteVTP/ I am strugg…

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## [Multiple Scalars per Cell or Face](https://discourse.vtk.org/t/multiple-scalars-per-cell-or-face/2493)

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**Author:** [@akaszynski](https://discourse.vtk.org/u/akaszynski)\
**Replies:** 9\
**Last updated:** [April 28, 2020, 1:24pm UTC](https://discourse.vtk.org/t/multiple-scalars-per-cell-or-face/2493 "2020-04-28T13:24:05Z")

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Hello, Aside from array scalars, VTK currently supports point or cell scalars, which means either the scalars array needs to match the number of points or cells. I’d like to plot scalars such that each point of each ce…

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## [Should I enable or disable the VTK\_USE\_SYSTEM\_\* options when using cmake to config vtk.](https://discourse.vtk.org/t/should-i-enable-or-disable-the-vtk-use-system-options-when-using-cmake-to-config-vtk/3166)

<div class="topic-metadata">

**Author:** [@Hongyi\_Zhao](https://discourse.vtk.org/u/Hongyi_Zhao)\
**Replies:** 2\
**Last updated:** [April 27, 2020, 11:54pm UTC](https://discourse.vtk.org/t/should-i-enable-or-disable-the-vtk-use-system-options-when-using-cmake-to-config-vtk/3166 "2020-04-27T23:54:21Z")

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Hi, There are many VTK\_USE\_SYSTEM\_\* options when compiling vtk, say the following ones: -DVTK\_USE\_SYSTEM\_LIBRARIES=ON \\ -DVTK\_USE\_SYSTEM\_LIBPROJ4=OFF \\ -DVTK\_USE\_SYSTEM\_GL2PS=O…

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## [Custom image filter](https://discourse.vtk.org/t/custom-image-filter/3165)

<div class="topic-metadata">

**Author:** [@ShaneKirkbride](https://discourse.vtk.org/u/ShaneKirkbride)\
**Replies:** 0\
**Last updated:** [April 27, 2020, 8:38pm UTC](https://discourse.vtk.org/t/custom-image-filter/3165 "2020-04-27T20:38:47Z")

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I’d like to make a custom image filter. I did see the gauss filter. Similar to imfilter in matlab. I’d like to define my H matrix. I didn’t find anything on a search. Can I do this with vtk? Here is the link to imfilte…

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