# Support

**URL:** https://discourse.vtk.org/c/support/6.md?page=84

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

**Page:** 85

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## [Update 2D image](https://discourse.vtk.org/t/update-2d-image/7696)

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**Author:** [@jamsoft](https://discourse.vtk.org/u/jamsoft)\
**Replies:** 0\
**Last updated:** [January 21, 2022, 6:02pm UTC](https://discourse.vtk.org/t/update-2d-image/7696 "2022-01-21T18:02:48Z")

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Hello all, In my project, I need to cut the volume by plane, move the plane by the keyboard arrows and show the slice content. Everything works well with the following (part of) code: planeSagittal\_vtkPlane = vtk.v…

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## [Cube in cube](https://discourse.vtk.org/t/cube-in-cube/7366)

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**Author:** [@jamsoft](https://discourse.vtk.org/u/jamsoft)\
**Replies:** 5\
**Last updated:** [January 21, 2022, 5:16pm UTC](https://discourse.vtk.org/t/cube-in-cube/7366 "2022-01-21T17:16:36Z")

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Hello all, I have the following problem that I don’t know how to solve…: I’ve successfully created 3D volume (reconstruction) from the DICOM MRI slices. What I need now is to create (imaginary) cube that will progressiv…

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## [Problems with linking GLEW (in MXE build)](https://discourse.vtk.org/t/problems-with-linking-glew-in-mxe-build/7522)

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**Author:** [@Aziuth](https://discourse.vtk.org/u/Aziuth)\
**Replies:** 4\
**Last updated:** [January 21, 2022, 3:15pm UTC](https://discourse.vtk.org/t/problems-with-linking-glew-in-mxe-build/7522 "2022-01-21T15:15:50Z")

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I have a (C++) project using VTK (8.2) which I cross-compile to Windows using MXE (with cmake). The latter information is relevant since the MXE folder contains all the libraries, including Qt, VTK and GLEW, and has act…

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## [Compile vtk-9.1 with mingw-Error](https://discourse.vtk.org/t/compile-vtk-9-1-with-mingw-error/7464)

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**Author:** [@rockydut](https://discourse.vtk.org/u/rockydut)\
**Replies:** 6\
**Last updated:** [January 21, 2022, 2:07pm UTC](https://discourse.vtk.org/t/compile-vtk-9-1-with-mingw-error/7464 "2022-01-21T14:07:05Z")

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Dear all. When I compile vtk-9.1 with mingw, it shows the following errors. How to fix this error? When I delete the TestAngularPeriodicDataArray.cxx in the compile source, it can compile correctly, but my program shows…

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## [vtkDataObject subclassing example \[python\]](https://discourse.vtk.org/t/vtkdataobject-subclassing-example-python/7619)

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**Author:** [@Nicholas\_Yue](https://discourse.vtk.org/u/Nicholas_Yue)\
**Replies:** 2\
**Last updated:** [January 21, 2022, 1:24pm UTC](https://discourse.vtk.org/t/vtkdataobject-subclassing-example-python/7619 "2022-01-21T13:24:14Z")

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I would like to pass customised data types into and out of a vtkAlgorithm subclass Where can I find more python information about subclass vtkDataObject The following is the gist of my idea of what I am trying to achei…

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## [How to invert the single cell's normal ?](https://discourse.vtk.org/t/how-to-invert-the-single-cells-normal/7683)

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**Author:** [@AlexLuya](https://discourse.vtk.org/u/AlexLuya)\
**Replies:** 1\
**Last updated:** [January 21, 2022, 7:32am UTC](https://discourse.vtk.org/t/how-to-invert-the-single-cells-normal/7683 "2022-01-21T07:32:46Z")

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Hello,I knew how to invert the all normal of an actor,question is how to inver the cell normal of a single cell?

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## [vtkProperty missing GetAllTextures() on Python](https://discourse.vtk.org/t/vtkproperty-missing-getalltextures-on-python/7692)

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**Author:** [@xtecox](https://discourse.vtk.org/u/xtecox)\
**Replies:** 1\
**Last updated:** [January 20, 2022, 4:17pm UTC](https://discourse.vtk.org/t/vtkproperty-missing-getalltextures-on-python/7692 "2022-01-20T16:17:11Z")

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Hi, im still trying to access the vtktexture of an actor loaded by the gltfimporter, I tried accessing it on the actor.GetProperty().GetAllTextures() but the property doesn’t have this function, was it ported to python?

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## [vtkPNGReader/vtkPNGWriter : Update() consistency ?](https://discourse.vtk.org/t/vtkpngreader-vtkpngwriter-update-consistency/7681)

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**Author:** [@Nicholas\_Yue](https://discourse.vtk.org/u/Nicholas_Yue)\
**Replies:** 3\
**Last updated:** [January 20, 2022, 1:51pm UTC](https://discourse.vtk.org/t/vtkpngreader-vtkpngwriter-update-consistency/7681 "2022-01-20T13:51:17Z")

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Hi, Calling Update() on vtkPNGReader performs a file read but calling Update() on vtkPNGWriter does not write out a proper PNG file, one has to call Write(), if I just call Update(), a file of the expected size is writt…

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## [vtkCellPicker unexpected work](https://discourse.vtk.org/t/vtkcellpicker-unexpected-work/7686)

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**Author:** [@zhang-qiang-github](https://discourse.vtk.org/u/zhang-qiang-github)\
**Replies:** 0\
**Last updated:** [January 20, 2022, 9:24am UTC](https://discourse.vtk.org/t/vtkcellpicker-unexpected-work/7686 "2022-01-20T09:24:59Z")

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I am using vtkCellPicker in my project, and I find it unexpected work. The code to reproduce my problem is: import vtk lineSource = vtk.vtkLineSource() lineSource.SetPoint1(0, 0, 0) lineSource.SetPoint2(512, 512, 0) l…

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## [vtkClipClosedSurface GenerateOutline - Width](https://discourse.vtk.org/t/vtkclipclosedsurface-generateoutline-width/7677)

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**Author:** [@mallikarjun49](https://discourse.vtk.org/u/mallikarjun49)\
**Replies:** 4\
**Last updated:** [January 20, 2022, 5:08am UTC](https://discourse.vtk.org/t/vtkclipclosedsurface-generateoutline-width/7677 "2022-01-20T05:08:57Z")

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Hi All, I am using vtkClipClosedSurface filter to clip and close the polydata and also to generate the outline where ever the planes intersect with the polydata. I managed to give a separate color to outline by overridd…

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## [Dicom reslice upside down problem](https://discourse.vtk.org/t/dicom-reslice-upside-down-problem/7631)

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**Author:** [@syj](https://discourse.vtk.org/u/syj)\
**Replies:** 3\
**Last updated:** [January 19, 2022, 3:32pm UTC](https://discourse.vtk.org/t/dicom-reslice-upside-down-problem/7631 "2022-01-19T15:32:20Z")

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Hi guys, I import dicom data Using vtkDICOMImageReader(). The 3-plane result is upside-down, as follows: But if I convert the DICOM files to .mha or .nii.gz, and using vtk to visualize them, there is no upside-d…

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## [QVTKOpenGLNativeWidget requires a \`vtkGenericOpenGLRenderWindow\`. \` vtkWin32OpenGLRenderWindow \` is not supported.](https://discourse.vtk.org/t/qvtkopenglnativewidget-requires-a-vtkgenericopenglrenderwindow-vtkwin32openglrenderwindow-is-not-supported/4127)

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**Author:** [@giri\_lakshman](https://discourse.vtk.org/u/giri_lakshman)\
**Replies:** 17\
**Last updated:** [January 19, 2022, 12:04pm UTC](https://discourse.vtk.org/t/qvtkopenglnativewidget-requires-a-vtkgenericopenglrenderwindow-vtkwin32openglrenderwindow-is-not-supported/4127 "2022-01-19T12:04:31Z")

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Hi, I am using Qt 5.15.0 framework and my VTK version is 9.0. I am new to VTK and I am working on reading the DICOM image application in Qt framework using VTK. The application is showing the DICOM image in a separate…

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## [Does vtkRenderer consider the direction of vtkImageData?](https://discourse.vtk.org/t/does-vtkrenderer-consider-the-direction-of-vtkimagedata/5949)

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**Author:** [@zhang-qiang-github](https://discourse.vtk.org/u/zhang-qiang-github)\
**Replies:** 8\
**Last updated:** [January 19, 2022, 8:45am UTC](https://discourse.vtk.org/t/does-vtkrenderer-consider-the-direction-of-vtkimagedata/5949 "2022-01-19T08:45:21Z")

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I want to show a image with vtkImageActor, and there is no other prop. I hope the image is shown in the center of screen, so I apply ResetCamera. However, the shown image is strange: But the image should be: And th…

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## [About vtkbool remote compile for python](https://discourse.vtk.org/t/about-vtkbool-remote-compile-for-python/7662)

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**Author:** [@timeanddoctor](https://discourse.vtk.org/u/timeanddoctor)\
**Replies:** 6\
**Last updated:** [January 19, 2022, 12:33am UTC](https://discourse.vtk.org/t/about-vtkbool-remote-compile-for-python/7662 "2022-01-19T00:33:40Z")

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I tend to compile the vtkbool from GitHub - zippy84/vtkbool: A new boolean operations filter for VTK And I add the remote D:\\vtk\\VTK-8.2.0\\Remote such as : # # A new boolean operations filter for VTK by Ronald Romer …

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## [How to access cells from in an octant/bin in a vtkStaticCellLocator?](https://discourse.vtk.org/t/how-to-access-cells-from-in-an-octant-bin-in-a-vtkstaticcelllocator/7660)

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**Author:** [@scotsman60](https://discourse.vtk.org/u/scotsman60)\
**Replies:** 10\
**Last updated:** [January 18, 2022, 10:02pm UTC](https://discourse.vtk.org/t/how-to-access-cells-from-in-an-octant-bin-in-a-vtkstaticcelllocator/7660 "2022-01-18T22:02:53Z")

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Hello!!! I want to recover the list/array of cells associated with an octant/bin in a vtkStaticCellLocator, but I don’t see any access methods on the locator to get this info. What am I missing? Thanks in advance, Do…

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## [How to access the texture on actors loaded by GLFTImporter](https://discourse.vtk.org/t/how-to-access-the-texture-on-actors-loaded-by-glftimporter/7673)

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**Author:** [@xtecox](https://discourse.vtk.org/u/xtecox)\
**Replies:** 0\
**Last updated:** [January 18, 2022, 5:36pm UTC](https://discourse.vtk.org/t/how-to-access-the-texture-on-actors-loaded-by-glftimporter/7673 "2022-01-18T17:36:06Z")

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Hi, im loading an glft using the glftimporter importer = vtkGLTFImporter() importer.SetFileName("/home/thiago/Downloads/factory\_3d\_model\_1/scene.gltf") importer.SetRenderWindow(renWin) importer.Update() after loadin…

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## [How to make the three cross sections show different colors like the flowing:](https://discourse.vtk.org/t/how-to-make-the-three-cross-sections-show-different-colors-like-the-flowing/7654)

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**Author:** [@wulicheng](https://discourse.vtk.org/u/wulicheng)\
**Replies:** 1\
**Last updated:** [January 18, 2022, 5:24am UTC](https://discourse.vtk.org/t/how-to-make-the-three-cross-sections-show-different-colors-like-the-flowing/7654 "2022-01-18T05:24:55Z")

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this this the axiel.

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## [python example code for vtkPolygon.ComputeCentroid](https://discourse.vtk.org/t/python-example-code-for-vtkpolygon-computecentroid/7655)

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**Author:** [@Dgg820502](https://discourse.vtk.org/u/Dgg820502)\
**Replies:** 0\
**Last updated:** [January 17, 2022, 11:30am UTC](https://discourse.vtk.org/t/python-example-code-for-vtkpolygon-computecentroid/7655 "2022-01-17T11:30:41Z")

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I try to get the Centroid data for a input polydata figure. Please let me know if there is python code for realizing my idea? Many thanks in advance. David.

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## [Get surface area of region on polydata](https://discourse.vtk.org/t/get-surface-area-of-region-on-polydata/3738)

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**Author:** [@rjs44](https://discourse.vtk.org/u/rjs44)\
**Replies:** 10\
**Last updated:** [January 16, 2022, 4:24am UTC](https://discourse.vtk.org/t/get-surface-area-of-region-on-polydata/3738 "2022-01-16T04:24:09Z")

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I would like to derive the surface area of a specific region on the surface of polydata. This specific region would be the part of the surface that is visible when viewed from above (in the y-plane) such that overlapping…

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## [How to flip the normals of partial cells of a polydata?](https://discourse.vtk.org/t/how-to-flip-the-normals-of-partial-cells-of-a-polydata/7642)

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**Author:** [@AlexLuya](https://discourse.vtk.org/u/AlexLuya)\
**Replies:** 0\
**Last updated:** [January 15, 2022, 7:24am UTC](https://discourse.vtk.org/t/how-to-flip-the-normals-of-partial-cells-of-a-polydata/7642 "2022-01-15T07:24:37Z")

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Hello,I knew how to flip all normal of a poly data,the question is : how to flip the normals of partial cells of a poly data?

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## [extract image slice from vtkImageData and convert it to qimage, which make unexpected result](https://discourse.vtk.org/t/extract-image-slice-from-vtkimagedata-and-convert-it-to-qimage-which-make-unexpected-result/7623)

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**Author:** [@xianger.qi](https://discourse.vtk.org/u/xianger.qi)\
**Replies:** 8\
**Last updated:** [January 14, 2022, 4:53am UTC](https://discourse.vtk.org/t/extract-image-slice-from-vtkimagedata-and-convert-it-to-qimage-which-make-unexpected-result/7623 "2022-01-14T04:53:26Z")

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Hello guys: I extract a slice from vtkImageData with vtkImageReslice filter, then display the output of vtkImageReslice in renderwindow, meanwhile i convert the output of vtkImageReslice to qimage. BUT The result of qim…

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## [vtkProbeFilter with oriented image](https://discourse.vtk.org/t/vtkprobefilter-with-oriented-image/7637)

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**Author:** [@Stephan\_Hahn](https://discourse.vtk.org/u/Stephan_Hahn)\
**Replies:** 2\
**Last updated:** [January 13, 2022, 8:12pm UTC](https://discourse.vtk.org/t/vtkprobefilter-with-oriented-image/7637 "2022-01-13T20:12:20Z")

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Hi all Maybe a question for @lassoan I have seen that vtkDiscreteMarchingCube has been updated for oriented image. And indeed the IndexToPhysicalMatrix is used through the TransformPoints method at the end of the metho…

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## [What does the parameter 'index' mean in GetScalarOpacity function? the volume, the point, the cell or others?](https://discourse.vtk.org/t/what-does-the-parameter-index-mean-in-getscalaropacity-function-the-volume-the-point-the-cell-or-others/7633)

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**Author:** [@YuezhenQin](https://discourse.vtk.org/u/YuezhenQin)\
**Replies:** 0\
**Last updated:** [January 13, 2022, 7:26am UTC](https://discourse.vtk.org/t/what-does-the-parameter-index-mean-in-getscalaropacity-function-the-volume-the-point-the-cell-or-others/7633 "2022-01-13T07:26:43Z")

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In doc, vtkPiecewiseFunction\* vtkVolumeProperty::GetScalarOpacity ( int index ) Get the scalar opacity transfer function for the given component. What does the component mean? How to use it? If there exist any example…

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## [How to set vtkPropCollection for vtkCellPicker](https://discourse.vtk.org/t/how-to-set-vtkpropcollection-for-vtkcellpicker/7624)

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**Author:** [@zhang-qiang-github](https://discourse.vtk.org/u/zhang-qiang-github)\
**Replies:** 2\
**Last updated:** [January 13, 2022, 3:39am UTC](https://discourse.vtk.org/t/how-to-set-vtkpropcollection-for-vtkcellpicker/7624 "2022-01-13T03:39:39Z")

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I find that vtkPropPicker can set the vtkPropCollection for pick: int PickProp( double selectionX, double selectionY, vtkRenderer\* renderer, vtkPropCollection\* pickfrom); This function allows to pick from the speci…

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## [Override DataArray values beyond set values](https://discourse.vtk.org/t/override-dataarray-values-beyond-set-values/7618)

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**Author:** [@theodorebaltis](https://discourse.vtk.org/u/theodorebaltis)\
**Replies:** 2\
**Last updated:** [January 12, 2022, 10:33pm UTC](https://discourse.vtk.org/t/override-dataarray-values-beyond-set-values/7618 "2022-01-12T22:33:34Z")

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I’m looking to set a new range on my data, assuming I have a new\_min and new\_max, so that values \> new\_max are set to new\_max and values \< new\_min are set to new\_min Easy enough to do with the vtk\_to\_numpy/numpy\_to\_vtk …

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## [vtkPointPicker very slow](https://discourse.vtk.org/t/vtkpointpicker-very-slow/7507)

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**Author:** [@Julienchz](https://discourse.vtk.org/u/Julienchz)\
**Replies:** 8\
**Last updated:** [January 12, 2022, 3:46pm UTC](https://discourse.vtk.org/t/vtkpointpicker-very-slow/7507 "2022-01-12T15:46:58Z")

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Hello ! I have a vtkPoints and I am trying to peak points from my pointcloud with cursor… so for now I am using vtkPointPicker… but with a large number of points, it is clearly too slow… The idea will be to use a vtkOct…

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## [convert VTK array to numpy array](https://discourse.vtk.org/t/convert-vtk-array-to-numpy-array/3152)

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**Author:** [@Deepa](https://discourse.vtk.org/u/Deepa)\
**Replies:** 4\
**Last updated:** [January 12, 2022, 1:14pm UTC](https://discourse.vtk.org/t/convert-vtk-array-to-numpy-array/3152 "2022-01-12T13:14:55Z")

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I have a VTKArray VTKArray(\[ -3.17113447, -16.9386692 , 16.73578644\], dtype=float32) I’m trying to convert this to a numpy array from vtk.util.numpy\_support import vtk\_to\_numpy vtk\_to\_numpy(edgeNode0\_pos) error: …

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## [Pick vtkActor from vtkPropAssembly](https://discourse.vtk.org/t/pick-vtkactor-from-vtkpropassembly/5005)

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**Author:** [@tgurgui](https://discourse.vtk.org/u/tgurgui)\
**Replies:** 1\
**Last updated:** [January 11, 2022, 5:49pm UTC](https://discourse.vtk.org/t/pick-vtkactor-from-vtkpropassembly/5005 "2022-01-11T17:49:21Z")

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Hello everyone, I’m trying to pick an actor from an assembly, but I’m always getting the first actor in the assembly as the picked actor. My understanding is that that I should get the picked actor from the path returne…

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## [How to get the opacity value at a point/cell (in world coordinate) on an object of vtkImageData](https://discourse.vtk.org/t/how-to-get-the-opacity-value-at-a-point-cell-in-world-coordinate-on-an-object-of-vtkimagedata/6691)

<div class="topic-metadata">

**Author:** [@YuezhenQin](https://discourse.vtk.org/u/YuezhenQin)\
**Replies:** 2\
**Last updated:** [January 11, 2022, 2:11pm UTC](https://discourse.vtk.org/t/how-to-get-the-opacity-value-at-a-point-cell-in-world-coordinate-on-an-object-of-vtkimagedata/6691 "2022-01-11T14:11:35Z")

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I made a line intersected with the vtkbox of vtkImageData volume and collected the intersection cell ids. I am wondering if vtk provide class or method to help me get the opacity value at each point/cell. Thanks! It has…

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## [Extract surface for selected cell ids from vtkUnstructuredGrid.](https://discourse.vtk.org/t/extract-surface-for-selected-cell-ids-from-vtkunstructuredgrid/7613)

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**Author:** [@Swarna\_Ravali](https://discourse.vtk.org/u/Swarna_Ravali)\
**Replies:** 0\
**Last updated:** [January 11, 2022, 11:18am UTC](https://discourse.vtk.org/t/extract-surface-for-selected-cell-ids-from-vtkunstructuredgrid/7613 "2022-01-11T11:18:29Z")

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Hi, I understand that vtkGeometryFilter() or vtkDataSetSurfaceFilter() is used to extract surfaces of vtkUnstructuredGrid. But Is there any possible way to extract surface of selected cells (non consecutive).? And SetC…

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