# Latest

**URL:** https://discourse.vtk.org/latest.md?page=205

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

**Page:** 206

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## [Xmlunstructuredgridwriter issue with time.](https://discourse.vtk.org/t/xmlunstructuredgridwriter-issue-with-time/3853)

<div class="topic-metadata">

**Author:** [@kayarre](https://discourse.vtk.org/u/kayarre)\
**Replies:** 2\
**Last updated:** [July 27, 2020, 7:27pm UTC](https://discourse.vtk.org/t/xmlunstructuredgridwriter-issue-with-time/3853 "2020-07-27T19:27:59Z")

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I have used the multi-time step feature successfully before in a python script, now I am trying to do something similar with c++. I tried it several ways, but something weird is happening that’s causes paraview to choke…

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## [How to change the size of the label on the vtkScalarBarActor?](https://discourse.vtk.org/t/how-to-change-the-size-of-the-label-on-the-vtkscalarbaractor/3532)

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**Author:** [@Kim\_William](https://discourse.vtk.org/u/Kim_William)\
**Replies:** 3\
**Last updated:** [July 27, 2020, 1:38pm UTC](https://discourse.vtk.org/t/how-to-change-the-size-of-the-label-on-the-vtkscalarbaractor/3532 "2020-07-27T13:38:16Z")

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Hi all! I would like to change the size of the label on the vtkScalarBarActor. The label size is too big, so I tried to change as below: vtkNew m\_vtkScalarBar; m\_vtkScalarBar-\>GetLabelTextProperty()-\>SetFontSize(10…

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## [vtkImageAppendComponents can be used for several 3D Image Data](https://discourse.vtk.org/t/vtkimageappendcomponents-can-be-used-for-several-3d-image-data/3845)

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**Author:** [@sharon](https://discourse.vtk.org/u/sharon)\
**Replies:** 2\
**Last updated:** [July 25, 2020, 6:49am UTC](https://discourse.vtk.org/t/vtkimageappendcomponents-can-be-used-for-several-3d-image-data/3845 "2020-07-25T06:49:55Z")

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Dear All, I have two 3D image data with same dimension, both of them have separate scalar, which can apply different color transfer function. What i want to do is merge the two 3D Image Data together with final color i…

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## [convert SimpleITK image to activiz vtkImageData in CSharp](https://discourse.vtk.org/t/convert-simpleitk-image-to-activiz-vtkimagedata-in-csharp/3673)

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**Author:** [@langderyos](https://discourse.vtk.org/u/langderyos)\
**Replies:** 5\
**Last updated:** [July 24, 2020, 6:43pm UTC](https://discourse.vtk.org/t/convert-simpleitk-image-to-activiz-vtkimagedata-in-csharp/3673 "2020-07-24T18:43:03Z")

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Hello, everyone. I’m trying to convert SimpleITK image to activiz vtkImageData in CSharp using vtkImageImport. I compared eyery pixel value after convert itk.simple.image.It seems ok but when I want to use the new vtkI…

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## [QVTKWidgetPlugin not found after upgrede to vtk9](https://discourse.vtk.org/t/qvtkwidgetplugin-not-found-after-upgrede-to-vtk9/3835)

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**Author:** [@mariasom](https://discourse.vtk.org/u/mariasom)\
**Replies:** 1\
**Last updated:** [July 24, 2020, 10:11am UTC](https://discourse.vtk.org/t/qvtkwidgetplugin-not-found-after-upgrede-to-vtk9/3835 "2020-07-24T10:11:49Z")

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hello, i’m trying to upgrade my vtk libraries for my project from version 8.2 to 9.0, but i had some issues while compiling them. In my project i’m also using qt libraries (v5.13.1). i suppose i haven’t correctly generat…

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## [Black VTK widget in pyqt5 with QWebEngine on Mac](https://discourse.vtk.org/t/black-vtk-widget-in-pyqt5-with-qwebengine-on-mac/3680)

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**Author:** [@tgurgui](https://discourse.vtk.org/u/tgurgui)\
**Replies:** 7\
**Last updated:** [July 24, 2020, 10:07am UTC](https://discourse.vtk.org/t/black-vtk-widget-in-pyqt5-with-qwebengine-on-mac/3680 "2020-07-24T10:07:16Z")

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Hello all, (I’ve post this question also in qt forum: https://forum.qt.io/topic/116371/qwebengineview-and-vtk-widget-on-mac) I’m building an application with a VTK widget (QVTKRenderWindowInteractor) to show 3D data an…

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## [Storing RGBA values directly to VTI file for 2D data](https://discourse.vtk.org/t/storing-rgba-values-directly-to-vti-file-for-2d-data/3830)

<div class="topic-metadata">

**Author:** [@sdutta](https://discourse.vtk.org/u/sdutta)\
**Replies:** 3\
**Last updated:** [July 24, 2020, 8:14am UTC](https://discourse.vtk.org/t/storing-rgba-values-directly-to-vti-file-for-2d-data/3830 "2020-07-24T08:14:51Z")

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I am wondering if it would be possible to store RGBA values into 2D VTI files instead of traditional data values. We are working on something which requires designing Opacity TF based on some criteria and we are trying t…

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## [vtkRenderWindow::Render() is extremely slow when using vtkDelaunay2D filter](https://discourse.vtk.org/t/vtkrenderwindow-render-is-extremely-slow-when-using-vtkdelaunay2d-filter/3834)

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**Author:** [@Tomasso](https://discourse.vtk.org/u/Tomasso)\
**Replies:** 4\
**Last updated:** [July 24, 2020, 12:44am UTC](https://discourse.vtk.org/t/vtkrenderwindow-render-is-extremely-slow-when-using-vtkdelaunay2d-filter/3834 "2020-07-24T00:44:08Z")

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I’ve subclassed vtkAbstractPolyDataReader to “GmtGridReader” that reads an x,y grid of elevations. I pass the output of the reader through a vtkDelaunay2D filter before displaying it. However when I read and filter the d…

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## [Size-dependent time cost of Delaunay3D filter](https://discourse.vtk.org/t/size-dependent-time-cost-of-delaunay3d-filter/3840)

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**Author:** [@jduriez](https://discourse.vtk.org/u/jduriez)\
**Replies:** 0\
**Last updated:** [July 23, 2020, 12:56pm UTC](https://discourse.vtk.org/t/size-dependent-time-cost-of-delaunay3d-filter/3840 "2020-07-23T12:56:05Z")

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Hi, I’m facing size (or unit)-dependent time costs when using Delaunay3D filter on a discrete scalar field, and do not understand those. I’m actually working on the distance field to some sphere, for gridpoints on a st…

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## [Point clouds on the surface of the cubes.](https://discourse.vtk.org/t/point-clouds-on-the-surface-of-the-cubes/3837)

<div class="topic-metadata">

**Author:** [@Mayank\_Srivastava](https://discourse.vtk.org/u/Mayank_Srivastava)\
**Replies:** 0\
**Last updated:** [July 23, 2020, 10:56am UTC](https://discourse.vtk.org/t/point-clouds-on-the-surface-of-the-cubes/3837 "2020-07-23T10:56:51Z")

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Hi, I’m trying to create point clouds of a cube in vtk. I have made a cube which is providing point clouds of the edges using vtkPoints from polydata. I want to create point clouds for the entire cube surface. If possib…

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## [How to show the rgb colors on a triangle mesh with rgb data defined on its points in Paraview?](https://discourse.vtk.org/t/how-to-show-the-rgb-colors-on-a-triangle-mesh-with-rgb-data-defined-on-its-points-in-paraview/3836)

<div class="topic-metadata">

**Author:** [@whymath](https://discourse.vtk.org/u/whymath)\
**Replies:** 0\
**Last updated:** [July 23, 2020, 10:44am UTC](https://discourse.vtk.org/t/how-to-show-the-rgb-colors-on-a-triangle-mesh-with-rgb-data-defined-on-its-points-in-paraview/3836 "2020-07-23T10:44:42Z")

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I have a triangle mesh which has NN points and a rgb data array with shape (NN, 3) defined on these points, and I want to show the rgb data as colors on this triangle mesh in Paraview. Any suggestion? Thanks very much.

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## [How to get a view inside a stl model](https://discourse.vtk.org/t/how-to-get-a-view-inside-a-stl-model/3817)

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**Author:** [@ThresholDDD](https://discourse.vtk.org/u/ThresholDDD)\
**Replies:** 2\
**Last updated:** [July 23, 2020, 5:57am UTC](https://discourse.vtk.org/t/how-to-get-a-view-inside-a-stl-model/3817 "2020-07-23T05:57:46Z")

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Hi, guys, I want to take virtual images inside a STL model. Like I have a head model, and then I want to take a picture of surface inside brain, how can I do that? I am new to vtk, many thanks!!! Best regards, Judy

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## [VTK Web - How to update server data source](https://discourse.vtk.org/t/vtk-web-how-to-update-server-data-source/3804)

<div class="topic-metadata">

**Author:** [@mqwang](https://discourse.vtk.org/u/mqwang)\
**Replies:** 4\
**Last updated:** [July 23, 2020, 2:54am UTC](https://discourse.vtk.org/t/vtk-web-how-to-update-server-data-source/3804 "2020-07-23T02:54:18Z")

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I am attempting to run VTK as a server, following this guide: http://kitware.github.io/paraviewweb/examples/RemoteRenderer.html#Using-VTK-as-server My question is how to update server data. I implementation MPR algorit…

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## [Multi-texture OBJ](https://discourse.vtk.org/t/multi-texture-obj/3775)

<div class="topic-metadata">

**Author:** [@panicbuttonvfx](https://discourse.vtk.org/u/panicbuttonvfx)\
**Replies:** 12\
**Last updated:** [July 23, 2020, 2:31am UTC](https://discourse.vtk.org/t/multi-texture-obj/3775 "2020-07-23T02:31:34Z")

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Hi, I’m trying to load an OBJ file with more than one texture, and I can’t seem to find a way to do that in VTK. Searching for possible solutions, I’ve found a very convoluted one to create an entity for each texture an…

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## [How to get color of an Image](https://discourse.vtk.org/t/how-to-get-color-of-an-image/3811)

<div class="topic-metadata">

**Author:** [@beginner](https://discourse.vtk.org/u/beginner)\
**Replies:** 2\
**Last updated:** [July 22, 2020, 10:27pm UTC](https://discourse.vtk.org/t/how-to-get-color-of-an-image/3811 "2020-07-22T22:27:05Z")

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Hello everyone, I am trying to create a colored mesh based on a png image. I see that I can use the GetProperty() function in vtkProperty class but how can I access this to get the colors pixel by pixel, to insert it in…

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## [Strange behaviour when removing actors](https://discourse.vtk.org/t/strange-behaviour-when-removing-actors/3796)

<div class="topic-metadata">

**Author:** [@Samuel\_James](https://discourse.vtk.org/u/Samuel_James)\
**Replies:** 1\
**Last updated:** [July 22, 2020, 5:05pm UTC](https://discourse.vtk.org/t/strange-behaviour-when-removing-actors/3796 "2020-07-22T17:05:49Z")

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Hi Everyone, First can I say that I’m new to React and VTK so apologies for my lack of knowledge. I’ve created some simple code that adds actors and removes all actors. When removing all actors the render does not remo…

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## [vtkSmartPointer\<MyClass\>](https://discourse.vtk.org/t/vtksmartpointer-myclass/2321)

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**Author:** [@Sohrab\_Azami](https://discourse.vtk.org/u/Sohrab_Azami)\
**Replies:** 6\
**Last updated:** [July 22, 2020, 4:41pm UTC](https://discourse.vtk.org/t/vtksmartpointer-myclass/2321 "2020-07-22T16:41:31Z")

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Hi, I would like to pass a regular c++ class to my vtkSmartPointer object, obviously I have difficulty to compile it! What I did I drived it from vtkObject class: class vtkFile : public vtkObject { private: std\>\>vec…

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## [Render window doesn't appear when running examples](https://discourse.vtk.org/t/render-window-doesnt-appear-when-running-examples/3826)

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**Author:** [@JenJen](https://discourse.vtk.org/u/JenJen)\
**Replies:** 1\
**Last updated:** [July 22, 2020, 3:55pm UTC](https://discourse.vtk.org/t/render-window-doesnt-appear-when-running-examples/3826 "2020-07-22T15:55:50Z")

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I am new to VTK. I have installed the latest version, using CMake and Visual Studio 2017 on Windows 10. I have download and compiled c++ examples (Sphere, PolyDataToImageData, and Glyph3DImage) but when I run the execu…

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## ["Could not find the VTK package with the following required components: RenderingContextOpenGL2."](https://discourse.vtk.org/t/could-not-find-the-vtk-package-with-the-following-required-components-renderingcontextopengl2/3778)

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**Author:** [@JenJen](https://discourse.vtk.org/u/JenJen)\
**Replies:** 5\
**Last updated:** [July 22, 2020, 3:25pm UTC](https://discourse.vtk.org/t/could-not-find-the-vtk-package-with-the-following-required-components-renderingcontextopengl2/3778 "2020-07-22T15:25:47Z")

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I am trying to run one of the examples “Glyph3DImage”, and also use vtkGlyph3DMapper in some other code. I am using the latest CMake and VTK9.0.0. The error “Could not find the VTK package with the following required c…

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## [Upcoming Khronos ANARI rendering webinar](https://discourse.vtk.org/t/upcoming-khronos-anari-rendering-webinar/3818)

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**Author:** [@Dave\_DeMarle](https://discourse.vtk.org/u/Dave_DeMarle)\
**Replies:** 0\
**Last updated:** [July 21, 2020, 1:23pm UTC](https://discourse.vtk.org/t/upcoming-khronos-anari-rendering-webinar/3818 "2020-07-21T13:23:50Z")

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Hi folks, If you would like to know more about plans for the next generation of the OSPRay/OptiX rendering infrastructure, sign up for this webinar on August 19’th. https://mailchi.mp/khronos/test-871146?e=af5273b617 c…

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## [vtkArray constructors or initializers try to free something and fail](https://discourse.vtk.org/t/vtkarray-constructors-or-initializers-try-to-free-something-and-fail/3810)

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**Author:** [@hugo-manet](https://discourse.vtk.org/u/hugo-manet)\
**Replies:** 2\
**Last updated:** [July 20, 2020, 6:07pm UTC](https://discourse.vtk.org/t/vtkarray-constructors-or-initializers-try-to-free-something-and-fail/3810 "2020-07-20T18:07:59Z")

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(copy-paste of https://gitlab.kitware.com/vtk/vtk/-/issues/17962) Hi, I’m having trouble with some (long) piece of code, part of a Paraview filter (part of the Topology ToolKit project). That code takes vtkMultiBlockD…

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## [Incorrect boundary of the intersection between two hexahedrons](https://discourse.vtk.org/t/incorrect-boundary-of-the-intersection-between-two-hexahedrons/3781)

<div class="topic-metadata">

**Author:** [@rodrigomologni](https://discourse.vtk.org/u/rodrigomologni)\
**Replies:** 6\
**Last updated:** [July 20, 2020, 3:59pm UTC](https://discourse.vtk.org/t/incorrect-boundary-of-the-intersection-between-two-hexahedrons/3781 "2020-07-20T15:59:45Z")

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Would anyone know how to solve this problem, please? I am using the vtkBooleanOperationPolyDataFilter class to produce the boundary of the intersection between two hexahedrons. Both hexahedrons are triangulated surfaces…

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## [vtkOpenGLHardwareSelect error when picking in combination with vtkSSAOPass](https://discourse.vtk.org/t/vtkopenglhardwareselect-error-when-picking-in-combination-with-vtkssaopass/3350)

<div class="topic-metadata">

**Author:** [@rdbrn](https://discourse.vtk.org/u/rdbrn)\
**Replies:** 3\
**Last updated:** [July 20, 2020, 12:02pm UTC](https://discourse.vtk.org/t/vtkopenglhardwareselect-error-when-picking-in-combination-with-vtkssaopass/3350 "2020-07-20T12:02:15Z")

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I’m getting the following error: vtkOpenGLHardwareSelect:199 ERR| vtkOpenGLHardwareSelector (0000020C7F641B90): Too many props. Currently only 16777214 props are supported. when picking a point using vtkPropPicker i…

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## [vtkArrayCalculator constant vector operation](https://discourse.vtk.org/t/vtkarraycalculator-constant-vector-operation/3807)

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**Author:** [@tkeskita](https://discourse.vtk.org/u/tkeskita)\
**Replies:** 0\
**Last updated:** [July 20, 2020, 6:07am UTC](https://discourse.vtk.org/t/vtkarraycalculator-constant-vector-operation/3807 "2020-07-20T06:07:44Z")

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A simple Python vtkArrayCalculator question: how can I specify a constant vector c in SetFunction so that I can do vector operation like U + c for an existing vector field U? I introduce U using AddVectorArrayName("U"). …

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## [Display of a 3D Image, in format I\[z\]\[y\]\[x\] located in GPU memory (Nvidia)](https://discourse.vtk.org/t/display-of-a-3d-image-in-format-i-z-y-x-located-in-gpu-memory-nvidia/3798)

<div class="topic-metadata">

**Author:** [@Luis\_Carlos\_Carneiro](https://discourse.vtk.org/u/Luis_Carlos_Carneiro)\
**Replies:** 2\
**Last updated:** [July 19, 2020, 7:55pm UTC](https://discourse.vtk.org/t/display-of-a-3d-image-in-format-i-z-y-x-located-in-gpu-memory-nvidia/3798 "2020-07-19T19:55:51Z")

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Dear All, I want to display a 3D image located in GPU, that I have the pointer, and it will allow rotation etc. I want to use the VTK in Python and I do not want to do transfers GPU-\>CPU of the image or vice-versa. Th…

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## [ERROR:root:Hardware does not support the number of textures defined.](https://discourse.vtk.org/t/errorhardware-does-not-support-the-number-of-textures-defined/3800)

<div class="topic-metadata">

**Author:** [@JANHMS](https://discourse.vtk.org/u/JANHMS)\
**Replies:** 1\
**Last updated:** [July 19, 2020, 5:14pm UTC](https://discourse.vtk.org/t/errorhardware-does-not-support-the-number-of-textures-defined/3800 "2020-07-19T17:14:24Z")

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Hey there, I am using VTK, I create several planes and set a texture on them with a for loop. I total 43 different ones. A snipped of my code. I a loop, where texture\[i\] is a list of textures: texturePlane = vtk.vtkT…

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## [Explicitly implement "modifiy" logic in RequestData method of a vtkAlgorithm Subclass?](https://discourse.vtk.org/t/explicitly-implement-modifiy-logic-in-requestdata-method-of-a-vtkalgorithm-subclass/3797)

<div class="topic-metadata">

**Author:** [@jaswantp](https://discourse.vtk.org/u/jaswantp)\
**Replies:** 1\
**Last updated:** [July 18, 2020, 1:10pm UTC](https://discourse.vtk.org/t/explicitly-implement-modifiy-logic-in-requestdata-method-of-a-vtkalgorithm-subclass/3797 "2020-07-18T13:10:05Z")

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When vtkAlgorithm (or) its sub-classes vtk\[UnstructuredGrid\], PolyData\],..\]Algorithm and the like are sub-classed, do I have to explicitly check mTime and do the processing only if it is required or is the magic all done…

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## [Save window rendering results to image](https://discourse.vtk.org/t/save-window-rendering-results-to-image/3772)

<div class="topic-metadata">

**Author:** [@Olga\_Ridzel](https://discourse.vtk.org/u/Olga_Ridzel)\
**Replies:** 2\
**Last updated:** [July 17, 2020, 6:32pm UTC](https://discourse.vtk.org/t/save-window-rendering-results-to-image/3772 "2020-07-17T18:32:04Z")

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Dear VTK team, I’m looking for a way to save my rendering results from the RenderWindow to an image in VTK.js. In python for example I did it using vtkWindowToImageFilter function but I cannot find something like this i…

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## [Interaction problem](https://discourse.vtk.org/t/interaction-problem/3766)

<div class="topic-metadata">

**Author:** [@Cheng1087](https://discourse.vtk.org/u/Cheng1087)\
**Replies:** 2\
**Last updated:** [July 17, 2020, 6:06am UTC](https://discourse.vtk.org/t/interaction-problem/3766 "2020-07-17T06:06:28Z")

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Two vtkSpheres are displayed in an actor, now I pick up a cell in vtkSphere, and then I need to highlight the selected vtkSphere. solutions: Change the polyData of the selected vtkSphere and assign different colors Bu…

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## [Hi all, is there anyone known multi-modal medical image fusion project,like CT/PET, CT/MRI and so on?](https://discourse.vtk.org/t/hi-all-is-there-anyone-known-multi-modal-medical-image-fusion-project-like-ct-pet-ct-mri-and-so-on/3788)

<div class="topic-metadata">

**Author:** [@wulicheng](https://discourse.vtk.org/u/wulicheng)\
**Replies:** 2\
**Last updated:** [July 17, 2020, 12:14am UTC](https://discourse.vtk.org/t/hi-all-is-there-anyone-known-multi-modal-medical-image-fusion-project-like-ct-pet-ct-mri-and-so-on/3788 "2020-07-17T00:14:22Z")

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Now I want to reseach the multi-modal medical image fusion, i want to find an open source project as first.

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