# Support

**URL:** https://discourse.vtk.org/c/support/6.md?page=85

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

**Page:** 86

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## [Distributed I/O with vtkXMLPUnstructuredGridWriter](https://discourse.vtk.org/t/distributed-i-o-with-vtkxmlpunstructuredgridwriter/7418)

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**Author:** [@Luke\_Dalessandro](https://discourse.vtk.org/u/Luke_Dalessandro)\
**Replies:** 4\
**Last updated:** [January 10, 2022, 7:33pm UTC](https://discourse.vtk.org/t/distributed-i-o-with-vtkxmlpunstructuredgridwriter/7418 "2022-01-10T19:33:03Z")

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Hi Everyone, We have our own solver that uses .vtu output via a vtkXMLUnstructuredGridWriter and synthesizes timeseries .pvds so that our domain scientists can use ParaView for post-processing. We’ve recently gone from …

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## [How to get vtkShaderProgram\* of an actor?](https://discourse.vtk.org/t/how-to-get-vtkshaderprogram-of-an-actor/7602)

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**Author:** [@WailmerPail](https://discourse.vtk.org/u/WailmerPail)\
**Replies:** 11\
**Last updated:** [January 10, 2022, 3:21pm UTC](https://discourse.vtk.org/t/how-to-get-vtkshaderprogram-of-an-actor/7602 "2022-01-10T15:21:19Z")

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Hi teams, I have already know void TestShaderCallback::Execute(vtkObject \*, unsigned long, void \*cbo){ auto cellBO = reinterpret\_cast\<vtkShaderProgram\*\>(cbo); float diffuseColor\[3\]{1,0.2,0.6}; cellBO-\>SetUn…

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## [Is there any simple to compute do product between cell normal and a vector like vtkVectorDot](https://discourse.vtk.org/t/is-there-any-simple-to-compute-do-product-between-cell-normal-and-a-vector-like-vtkvectordot/7608)

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**Author:** [@AlexLuya](https://discourse.vtk.org/u/AlexLuya)\
**Replies:** 2\
**Last updated:** [January 10, 2022, 1:26pm UTC](https://discourse.vtk.org/t/is-there-any-simple-to-compute-do-product-between-cell-normal-and-a-vector-like-vtkvectordot/7608 "2022-01-10T13:26:01Z")

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Hello,vtkVectorDot can be used to compute the dot product between POINT normal and vectors,any similar way for CELL normals?

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## [Help: Intrinsic Rotation on Object not working...](https://discourse.vtk.org/t/help-intrinsic-rotation-on-object-not-working/7500)

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**Author:** [@Charles\_Shin](https://discourse.vtk.org/u/Charles_Shin)\
**Replies:** 7\
**Last updated:** [January 10, 2022, 8:13am UTC](https://discourse.vtk.org/t/help-intrinsic-rotation-on-object-not-working/7500 "2022-01-10T08:13:44Z")

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I’m trying to do intrinsic rotation (not rotating camera!!) on a NIFTI image, but it is not working…I’ve been working on this for hours, and it is quite sad that it is still not working. I saw the documentation regardin…

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## [How to get voxel coordinates(as in ITK snap ) from vtkimage viewer from mouse click](https://discourse.vtk.org/t/how-to-get-voxel-coordinates-as-in-itk-snap-from-vtkimage-viewer-from-mouse-click/7607)

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**Author:** [@Sreerag](https://discourse.vtk.org/u/Sreerag)\
**Replies:** 0\
**Last updated:** [January 10, 2022, 6:01am UTC](https://discourse.vtk.org/t/how-to-get-voxel-coordinates-as-in-itk-snap-from-vtkimage-viewer-from-mouse-click/7607 "2022-01-10T06:01:05Z")

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Hello, I am trying to use ITK’s region growing algorithm for medical image segmentation. So to put the seedpoint i need exact voxel coordinates of the mouseclick position in my vtkimageviewer. So how can I get those vo…

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## [vtkTextActor3D looks weird](https://discourse.vtk.org/t/vtktextactor3d-looks-weird/7591)

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**Author:** [@zhang-qiang-github](https://discourse.vtk.org/u/zhang-qiang-github)\
**Replies:** 7\
**Last updated:** [January 9, 2022, 10:15pm UTC](https://discourse.vtk.org/t/vtktextactor3d-looks-weird/7591 "2022-01-09T22:15:58Z")

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I am using vtkTextActor3D to display 3D text, but it look weird.The code to reproduce my question is: import vtkmodules.all as vtk if \_\_name\_\_ == '\_\_main\_\_': line = vtk.vtkLineSource() line.SetPoint1(0, 0, 0) …

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## [Compile vtk-9.1 with mingw-Error, "file too big"](https://discourse.vtk.org/t/compile-vtk-9-1-with-mingw-error-file-too-big/7590)

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**Author:** [@rockydut](https://discourse.vtk.org/u/rockydut)\
**Replies:** 3\
**Last updated:** [January 8, 2022, 1:19am UTC](https://discourse.vtk.org/t/compile-vtk-9-1-with-mingw-error-file-too-big/7590 "2022-01-08T01:19:31Z")

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When I compile VTK-9.1 by mingw. I selected the vtkm. The compiler said: UnknownArrayHandle.cxx.obj: too many sections (79466) UnknownArrayHandle.cxx.obj: ‘file too big’. So, how to compile it correctly?

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## [Display based on vtk cannot be displayed normally on vmware virtual machine](https://discourse.vtk.org/t/display-based-on-vtk-cannot-be-displayed-normally-on-vmware-virtual-machine/7586)

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**Author:** [@WangZP10969](https://discourse.vtk.org/u/WangZP10969)\
**Replies:** 3\
**Last updated:** [January 7, 2022, 10:10am UTC](https://discourse.vtk.org/t/display-based-on-vtk-cannot-be-displayed-normally-on-vmware-virtual-machine/7586 "2022-01-07T10:10:01Z")

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VMWare: 16 Windows10x64 VTK9 (compiled via vcpkg) Operation: open the vtk window Result: VMWare rendering error PC rendering normally VTK did not prompt any warnings. What could cause this situation?

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## [cannot create object of unknown type "vtkColor3d"](https://discourse.vtk.org/t/cannot-create-object-of-unknown-type-vtkcolor3d/7595)

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**Author:** [@perphy](https://discourse.vtk.org/u/perphy)\
**Replies:** 0\
**Last updated:** [January 7, 2022, 9:30am UTC](https://discourse.vtk.org/t/cannot-create-object-of-unknown-type-vtkcolor3d/7595 "2022-01-07T09:30:16Z")

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I am trying the helloworld example in python in vtk9.1. I get an error when calling colors.GetColor3d(“Tomato”) which comes from the tutorial code. I tried “blue”, and same problem. Thanks #!/usr/bin/env python # …

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## [Ask for help, I use the mouse to delimit 3 d line, at the beginning is right, but as long as the mouse rotated the camera to delimit again error,line posion is error, do not know what reason is](https://discourse.vtk.org/t/ask-for-help-i-use-the-mouse-to-delimit-3-d-line-at-the-beginning-is-right-but-as-long-as-the-mouse-rotated-the-camera-to-delimit-again-error-line-posion-is-error-do-not-know-what-reason-is/7588)

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**Author:** [@Liudeke](https://discourse.vtk.org/u/Liudeke)\
**Replies:** 0\
**Last updated:** [January 7, 2022, 6:56am UTC](https://discourse.vtk.org/t/ask-for-help-i-use-the-mouse-to-delimit-3-d-line-at-the-beginning-is-right-but-as-long-as-the-mouse-rotated-the-camera-to-delimit-again-error-line-posion-is-error-do-not-know-what-reason-is/7588 "2022-01-07T06:56:16Z")

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## [vtkProbeFilter fails in 2D](https://discourse.vtk.org/t/vtkprobefilter-fails-in-2d/7525)

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**Author:** [@Danial\_Mohajery](https://discourse.vtk.org/u/Danial_Mohajery)\
**Replies:** 1\
**Last updated:** [January 7, 2022, 5:42am UTC](https://discourse.vtk.org/t/vtkprobefilter-fails-in-2d/7525 "2022-01-07T05:42:07Z")

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Hi all, I am trying to probe a planar source (fig1) with a sector-like input (fig2), which is also planar. However, I get this weird output (fig 3). Here is my code: sector\_avg = True filler = vtk.vtkContourTriangulato…

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## [Why there is a visual dislocation when I show two volume models in a window.](https://discourse.vtk.org/t/why-there-is-a-visual-dislocation-when-i-show-two-volume-models-in-a-window/7489)

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**Author:** [@DDS](https://discourse.vtk.org/u/DDS)\
**Replies:** 1\
**Last updated:** [January 7, 2022, 1:06am UTC](https://discourse.vtk.org/t/why-there-is-a-visual-dislocation-when-i-show-two-volume-models-in-a-window/7489 "2022-01-07T01:06:57Z")

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These two models have only displacement in the XY direction. But after rotating the view angle, it looks overlapping. How to make it right ? What below is the codes. I’m a beginner. Thanks for help. // Create a vt…

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## [Filters with non-optional ports ?](https://discourse.vtk.org/t/filters-with-non-optional-ports/7583)

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**Author:** [@Nicholas\_Yue](https://discourse.vtk.org/u/Nicholas_Yue)\
**Replies:** 2\
**Last updated:** [January 7, 2022, 12:48am UTC](https://discourse.vtk.org/t/filters-with-non-optional-ports/7583 "2022-01-07T00:48:30Z")

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Hi, I am looking for vtkAlgorithm derived classes in VTK that requires two or more non-optional inputs ? Any recommendations ? At this stage of my VTK study, I am not after repeatable inputs yet. Cheers

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## [How to accelerate render?](https://discourse.vtk.org/t/how-to-accelerate-render/7553)

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**Author:** [@zhang-qiang-github](https://discourse.vtk.org/u/zhang-qiang-github)\
**Replies:** 3\
**Last updated:** [January 6, 2022, 1:22pm UTC](https://discourse.vtk.org/t/how-to-accelerate-render/7553 "2022-01-06T13:22:54Z")

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If there are several actors in the vtk, is it possible to accelerate render by only render one actor? For example: // dong something to change actor1 renderWindow-\>Render(actor1); // or a similar method?

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## [How can I convert Vtk STL polydata into opencascade poly\_triangulation and vise versa ?](https://discourse.vtk.org/t/how-can-i-convert-vtk-stl-polydata-into-opencascade-poly-triangulation-and-vise-versa/7568)

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**Author:** [@osezer](https://discourse.vtk.org/u/osezer)\
**Replies:** 3\
**Last updated:** [January 6, 2022, 11:12am UTC](https://discourse.vtk.org/t/how-can-i-convert-vtk-stl-polydata-into-opencascade-poly-triangulation-and-vise-versa/7568 "2022-01-06T11:12:57Z")

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Hello, I would like to convert opencascade’s poly\_triangulation(occt) into VTK polydata and visualize it, or otherway around as well. vtk polydata to poly\_triangulation (occt). I didn’t find any proper document or exam…

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## [Add custom dataset associated to points d'un pointcloud](https://discourse.vtk.org/t/add-custom-dataset-associated-to-points-dun-pointcloud/7565)

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**Author:** [@Julienchz](https://discourse.vtk.org/u/Julienchz)\
**Replies:** 0\
**Last updated:** [January 5, 2022, 8:55am UTC](https://discourse.vtk.org/t/add-custom-dataset-associated-to-points-dun-pointcloud/7565 "2022-01-05T08:55:51Z")

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Hello, I want to associate data with each point of my pointcloud. To do that I know I could use a GetPointData()-\>SetScalars(…) from vtkPolyData but the active scalar of a vtkPointData corresponds to the color of the p…

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## [Extent attributes in StructuredGrid](https://discourse.vtk.org/t/extent-attributes-in-structuredgrid/7472)

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**Author:** [@Toha](https://discourse.vtk.org/u/Toha)\
**Replies:** 4\
**Last updated:** [January 5, 2022, 8:00am UTC](https://discourse.vtk.org/t/extent-attributes-in-structuredgrid/7472 "2022-01-05T08:00:35Z")

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Dear users, I am trying to output my numerical simulation data in vtk format. My grid is structured and I need to use the VTK’s XML format. My greatest confusion is about the WholeExtent and the Piece Extent attribute…

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## [Interacting with slices in layered Renderers](https://discourse.vtk.org/t/interacting-with-slices-in-layered-renderers/7557)

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**Author:** [@Valentin\_Regueiro](https://discourse.vtk.org/u/Valentin_Regueiro)\
**Replies:** 0\
**Last updated:** [January 4, 2022, 12:10pm UTC](https://discourse.vtk.org/t/interacting-with-slices-in-layered-renderers/7557 "2022-01-04T12:10:21Z")

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Hi everyone, my project is using a vtkImageViewer2 with two renderers used to display volume slices. One renderer has a blend of ImageData (PET scans), the other one is used to superimpose segmentated parts (vtkActors)…

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## [Generate array with partial pixel information from shapes](https://discourse.vtk.org/t/generate-array-with-partial-pixel-information-from-shapes/7459)

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**Author:** [@daberle](https://discourse.vtk.org/u/daberle)\
**Replies:** 2\
**Last updated:** [January 3, 2022, 11:28pm UTC](https://discourse.vtk.org/t/generate-array-with-partial-pixel-information-from-shapes/7459 "2022-01-03T23:28:50Z")

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Can I create a polygon or shape of some sort in VTK and then get access to the raw data such that I can convert it to a 2D or 3D array of type float or double? When I do this I would like to also save partial pixel info…

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## [Adding renderer to renderer window](https://discourse.vtk.org/t/adding-renderer-to-renderer-window/7494)

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**Author:** [@Taimour](https://discourse.vtk.org/u/Taimour)\
**Replies:** 1\
**Last updated:** [January 3, 2022, 4:52pm UTC](https://discourse.vtk.org/t/adding-renderer-to-renderer-window/7494 "2022-01-03T16:52:33Z")

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Can someone explain what is wrong with this code? It crashes on third line when ren is added to the renderer window. I am working MDI application. this-\>ren = vtkRenderer::New(); this-\>renWin = vtkWin32OpenGLRenderWin…

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## [I'm not able to change the default colormap in VTK (python)](https://discourse.vtk.org/t/im-not-able-to-change-the-default-colormap-in-vtk-python/7546)

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**Author:** [@Altertango](https://discourse.vtk.org/u/Altertango)\
**Replies:** 0\
**Last updated:** [January 2, 2022, 9:39pm UTC](https://discourse.vtk.org/t/im-not-able-to-change-the-default-colormap-in-vtk-python/7546 "2022-01-02T21:39:16Z")

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Hello and happy new year to everyone, I’m trying to import some triangulated surfaces DEMs (digital elevation models) from a csv file to vtk. I have no problem importing the file and creating the triangles in VTK, I als…

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## [vtk\_modules warning in CMake Project](https://discourse.vtk.org/t/vtk-modules-warning-in-cmake-project/7530)

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**Author:** [@Michael\_Jackson](https://discourse.vtk.org/u/Michael_Jackson)\
**Replies:** 1\
**Last updated:** [January 2, 2022, 9:27pm UTC](https://discourse.vtk.org/t/vtk-modules-warning-in-cmake-project/7530 "2022-01-02T21:27:08Z")

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When I configure my project that uses VTK I am consistently getting this error: No \`MODULES\` passed to \`vtk\_modules\_autoinit\`. Call Stack (most recent call first): common/CMakeLists.txt:42 (vtk\_module\_autoinit) This…

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## [Python example code for splineWidget.GetSummedLength](https://discourse.vtk.org/t/python-example-code-for-splinewidget-getsummedlength/7529)

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**Author:** [@Dgg820502](https://discourse.vtk.org/u/Dgg820502)\
**Replies:** 5\
**Last updated:** [December 31, 2021, 11:54am UTC](https://discourse.vtk.org/t/python-example-code-for-splinewidget-getsummedlength/7529 "2021-12-31T11:54:03Z")

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I am trying use splineWidget.GetSummedLength() to get the length of spline, but I always get the same length data no matter how I moved spline around. Please let know if there is example code for splineWidget.GetSummedL…

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## [Extract volume from vtkImageData](https://discourse.vtk.org/t/extract-volume-from-vtkimagedata/7448)

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**Author:** [@Valentin\_Regueiro](https://discourse.vtk.org/u/Valentin_Regueiro)\
**Replies:** 1\
**Last updated:** [December 31, 2021, 9:59am UTC](https://discourse.vtk.org/t/extract-volume-from-vtkimagedata/7448 "2021-12-31T09:59:22Z")

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Hi everyone, I’m running a segmentation which produces various separate volumes that are then added to a vtkRenderer as vtkActors. The problem is, that the bounds of this volumes (vtkImageData) correspond to the bounds…

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## [Creating actors after vtkImageBlend](https://discourse.vtk.org/t/creating-actors-after-vtkimageblend/7434)

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**Author:** [@Valentin\_Regueiro](https://discourse.vtk.org/u/Valentin_Regueiro)\
**Replies:** 1\
**Last updated:** [December 31, 2021, 9:58am UTC](https://discourse.vtk.org/t/creating-actors-after-vtkimageblend/7434 "2021-12-31T09:58:43Z")

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Hello everyone, first of all I’m a noob trying to learn VTK so excuse me if the question seems unnecessary. I can not find an answer anywhere. Right now I am getting vtkImageData from nifti Images, which is passed thro…

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## [Annoying Dots in Snapshots on Volume Render](https://discourse.vtk.org/t/annoying-dots-in-snapshots-on-volume-render/7535)

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**Author:** [@tigerhu7](https://discourse.vtk.org/u/tigerhu7)\
**Replies:** 1\
**Last updated:** [December 31, 2021, 1:58am UTC](https://discourse.vtk.org/t/annoying-dots-in-snapshots-on-volume-render/7535 "2021-12-31T01:58:55Z")

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I have an issue on taking snapshots on volume render visualization. The following is my procedure. \[1\] add renderer ren1 = vtk.vtkRenderer() ren1.AddVolume(volume) ren1.SetBackground(0,0,0) ren1.GetActiveCamera().…

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## [Obtaining graph relationships of filters and connections ?](https://discourse.vtk.org/t/obtaining-graph-relationships-of-filters-and-connections/7536)

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**Author:** [@Nicholas\_Yue](https://discourse.vtk.org/u/Nicholas_Yue)\
**Replies:** 0\
**Last updated:** [December 31, 2021, 1:49am UTC](https://discourse.vtk.org/t/obtaining-graph-relationships-of-filters-and-connections/7536 "2021-12-31T01:49:03Z")

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In the C++ api, after creating various filters and connecting them is there some API or mechanism to find out the graph of the connections and hopefully find the leaf/sink nodes where calling Update() will exercise the g…

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## [Histogram from vtkTable](https://discourse.vtk.org/t/histogram-from-vtktable/7519)

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**Author:** [@drpeterfranz](https://discourse.vtk.org/u/drpeterfranz)\
**Replies:** 4\
**Last updated:** [December 30, 2021, 8:34pm UTC](https://discourse.vtk.org/t/histogram-from-vtktable/7519 "2021-12-30T20:34:25Z")

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I can’t find an appropriate filter to generate a 1D histogram from a vtkTable. There are classes to generate 2D histograms from images etc. I also found vtkmHistogram but when I build against the required variables then …

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## [How to set the property for a 3D text?](https://discourse.vtk.org/t/how-to-set-the-property-for-a-3d-text/7528)

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**Author:** [@zhang-qiang-github](https://discourse.vtk.org/u/zhang-qiang-github)\
**Replies:** 0\
**Last updated:** [December 30, 2021, 9:30am UTC](https://discourse.vtk.org/t/how-to-set-the-property-for-a-3d-text/7528 "2021-12-30T09:30:10Z")

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I want to add 3D text in my application, and vtkVectorText may help: vtkSmartPointer\<vtkVectorText\> text = vtkSmartPointer\<vtkVectorText\>::New(); text-\>SetText("hello, world"); text-\>Update(); vtkSmartPointer\<vtkPolyDa…

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## [Support of new/additional image format ?](https://discourse.vtk.org/t/support-of-new-additional-image-format/7524)

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**Author:** [@Nicholas\_Yue](https://discourse.vtk.org/u/Nicholas_Yue)\
**Replies:** 1\
**Last updated:** [December 30, 2021, 9:22am UTC](https://discourse.vtk.org/t/support-of-new-additional-image-format/7524 "2021-12-30T09:22:52Z")

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Hi, Where and which class should I study if I want to support additional image format in VTK ? Cheers

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