# Latest

**URL:** https://discourse.vtk.org/latest.md?page=202

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

**Page:** 203

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## [Convert Vertex and Index Buffers to vtkPolyData for vtkDecimatePro](https://discourse.vtk.org/t/convert-vertex-and-index-buffers-to-vtkpolydata-for-vtkdecimatepro/4057)

<div class="topic-metadata">

**Author:** [@Robin](https://discourse.vtk.org/u/Robin)\
**Replies:** 1\
**Last updated:** [August 24, 2020, 3:36pm UTC](https://discourse.vtk.org/t/convert-vertex-and-index-buffers-to-vtkpolydata-for-vtkdecimatepro/4057 "2020-08-24T15:36:21Z")

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Hello, I’m trying to decimate a mesh using vtkDecimatePro. The mesh is represented as a vertex list with a list of indices referencing the corresponding vertices. E.g: Vertices: {0f, 0f, 0f}, {1f, 0f, 0f}, {0f, 1f…

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## [move single actor out of multiple actors in a renderer](https://discourse.vtk.org/t/move-single-actor-out-of-multiple-actors-in-a-renderer/2899)

<div class="topic-metadata">

**Author:** [@Pratul\_Patwari](https://discourse.vtk.org/u/Pratul_Patwari)\
**Replies:** 6\
**Last updated:** [August 24, 2020, 3:05pm UTC](https://discourse.vtk.org/t/move-single-actor-out-of-multiple-actors-in-a-renderer/2899 "2020-08-24T15:05:25Z")

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Hello, I have a renderWindow in vtk.js with two actors (vtkImageSlice and vtkActor). I want to change the position and orientation of vtkActor with cylinder source using user interaction like mouse click and drag. I can…

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## [World Rotation in 3D](https://discourse.vtk.org/t/world-rotation-in-3d/4020)

<div class="topic-metadata">

**Author:** [@AlexG](https://discourse.vtk.org/u/AlexG)\
**Replies:** 3\
**Last updated:** [August 24, 2020, 3:04pm UTC](https://discourse.vtk.org/t/world-rotation-in-3d/4020 "2020-08-24T15:04:26Z")

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Hi, I have a question concerning the rotation of the whole VR Environment. With the currently implemented OnPinch() and OnPan() Methods the whole environment can be scaled and moved. Now i want to use the OnRotate() me…

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## [vtkParametricFunction Class on VTK.js](https://discourse.vtk.org/t/vtkparametricfunction-class-on-vtk-js/4048)

<div class="topic-metadata">

**Author:** [@Souleymane0](https://discourse.vtk.org/u/Souleymane0)\
**Replies:** 1\
**Last updated:** [August 24, 2020, 2:53pm UTC](https://discourse.vtk.org/t/vtkparametricfunction-class-on-vtk-js/4048 "2020-08-24T14:53:05Z")

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Hello, I want to visualize Parametric surfaces using VTK.js and I was wondering if there is the extention of the vtkParametricFunction Class in VTK.js as well, because I didn’t find it on the library. If there isn’t su…

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## [Stack of PNG files to be rendered as 3D](https://discourse.vtk.org/t/stack-of-png-files-to-be-rendered-as-3d/4040)

<div class="topic-metadata">

**Author:** [@anand](https://discourse.vtk.org/u/anand)\
**Replies:** 6\
**Last updated:** [August 24, 2020, 6:29am UTC](https://discourse.vtk.org/t/stack-of-png-files-to-be-rendered-as-3d/4040 "2020-08-24T06:29:58Z")

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Hi Team, I’m looking for option in C++ example where I can convert stack of 2D images (PNG format) to render 3D object. Any help would be greatly appreciated. Regards, Anand

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## [Install vtk-8.2.0 in ARM64/aarch64](https://discourse.vtk.org/t/install-vtk-8-2-0-in-arm64-aarch64/4051)

<div class="topic-metadata">

**Author:** [@koilgg](https://discourse.vtk.org/u/koilgg)\
**Replies:** 0\
**Last updated:** [August 23, 2020, 4:00am UTC](https://discourse.vtk.org/t/install-vtk-8-2-0-in-arm64-aarch64/4051 "2020-08-23T04:00:39Z")

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Hello, I am trying to install vtk in my ubuntu(aarch64). I have tried several methods, but they were all failed. 1.I installed miniforge in ubuntu and downloaded the package 'vtk-8.2.0-py36haa4764d\_200.tar.bz2' from ht…

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## [Adding Roemer's Boolean Filter as a Remote Module](https://discourse.vtk.org/t/adding-roemers-boolean-filter-as-a-remote-module/1635)

<div class="topic-metadata">

**Author:** [@lorensen](https://discourse.vtk.org/u/lorensen)\
**Replies:** 37\
**Last updated:** [August 22, 2020, 7:08pm UTC](https://discourse.vtk.org/t/adding-roemers-boolean-filter-as-a-remote-module/1635 "2020-08-22T19:08:54Z")

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@Ron84 I am working on a Merge Request to add Roland Roemer’s Boolean operator filter as a Remote Module. Roemer’s class is supposedly more robust than the existing filters and has several features listed in the README.m…

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## [Apply transformation to nifiti image](https://discourse.vtk.org/t/apply-transformation-to-nifiti-image/4017)

<div class="topic-metadata">

**Author:** [@isuruwi](https://discourse.vtk.org/u/isuruwi)\
**Replies:** 5\
**Last updated:** [August 22, 2020, 7:02pm UTC](https://discourse.vtk.org/t/apply-transformation-to-nifiti-image/4017 "2020-08-22T19:02:47Z")

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I want to apply transformations to a given nifti image. How can I apply such as translate, scale, rotation to that? See below example for further reference. // read nifti image vtkSmartPointer niftiReader = vtkSmartPoi…

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## [undefined reference to 'ZN16QVTKOpenGLWidget'](https://discourse.vtk.org/t/undefined-reference-to-zn16qvtkopenglwidget/4024)

<div class="topic-metadata">

**Author:** [@Cesar\_Cherre](https://discourse.vtk.org/u/Cesar_Cherre)\
**Replies:** 1\
**Last updated:** [August 22, 2020, 3:02am UTC](https://discourse.vtk.org/t/undefined-reference-to-zn16qvtkopenglwidget/4024 "2020-08-22T03:02:59Z")

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Hi everyone, I have successfully installed VTK with MinGW64, I have imported the .dll and .h into .pro, but when I run a test code I get this: “…mainwindow.cpp:16: error: undefined reference to ‘imp\_\_ZN16QVTKOpenGLWidge…

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## [How to play the animation of GLTF model](https://discourse.vtk.org/t/how-to-play-the-animation-of-gltf-model/3939)

<div class="topic-metadata">

**Author:** [@yuhuimoon](https://discourse.vtk.org/u/yuhuimoon)\
**Replies:** 7\
**Last updated:** [August 22, 2020, 2:46am UTC](https://discourse.vtk.org/t/how-to-play-the-animation-of-gltf-model/3939 "2020-08-22T02:46:58Z")

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I have load a GLTF with a simple translation animation successfully by vtkGLTFReader int VTK 9.0.1. I want to play the animation. But I fail after using: gltfReader-\>EnableAnimation(0); //0 is the correct animation ind…

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## [Porting C++ app to VTK.js](https://discourse.vtk.org/t/porting-c-app-to-vtk-js/2303)

<div class="topic-metadata">

**Author:** [@LarryMartell59](https://discourse.vtk.org/u/LarryMartell59)\
**Replies:** 10\
**Last updated:** [August 21, 2020, 7:12pm UTC](https://discourse.vtk.org/t/porting-c-app-to-vtk-js/2303 "2020-08-21T19:12:19Z")

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We have an app written in C++ using Qt. The app used ITK to produce nrrd files and then uses VTK to render dicomm files with the nrrd files on top of them. We want to port this to a web app. Anyone have any experience do…

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## [How to create and manipulate stuff in vtkContext2D](https://discourse.vtk.org/t/how-to-create-and-manipulate-stuff-in-vtkcontext2d/4037)

<div class="topic-metadata">

**Author:** [@alejandronespereira](https://discourse.vtk.org/u/alejandronespereira)\
**Replies:** 2\
**Last updated:** [August 21, 2020, 3:59pm UTC](https://discourse.vtk.org/t/how-to-create-and-manipulate-stuff-in-vtkcontext2d/4037 "2020-08-21T15:59:04Z")

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I am drawing a 3D scene and some 2D slices of the scene on separate windows. If I try to render the full scene into a vectorized image with vtkExporterGL2PS, the output comes with invalid utf-8 characters that break the …

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## [Delete account](https://discourse.vtk.org/t/delete-account/4041)

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**Author:** [@anon10073585](https://discourse.vtk.org/u/anon10073585)\
**Replies:** 2\
**Last updated:** [August 21, 2020, 1:49pm UTC](https://discourse.vtk.org/t/delete-account/4041 "2020-08-21T13:49:38Z")

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I want to delete my account, but I cannot find a “Delete account” button anywhere. How can I do that?

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## [Regarding 3D image formation with vtkPNGReader](https://discourse.vtk.org/t/regarding-3d-image-formation-with-vtkpngreader/2391)

<div class="topic-metadata">

**Author:** [@snehal](https://discourse.vtk.org/u/snehal)\
**Replies:** 7\
**Last updated:** [August 21, 2020, 11:59am UTC](https://discourse.vtk.org/t/regarding-3d-image-formation-with-vtkpngreader/2391 "2020-08-21T11:59:39Z")

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I have total 12,000 .png images. Out of those, if I pass 2,000 images on vtkPNGReader() then it is possible to see their 3D images. But when this number increases (\>2,000) then it doesn’t show any kind of expected result…

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## [VTK\_USE\_FILE](https://discourse.vtk.org/t/vtk-use-file/3645)

<div class="topic-metadata">

**Author:** [@GeorgeS](https://discourse.vtk.org/u/GeorgeS)\
**Replies:** 8\
**Last updated:** [August 21, 2020, 7:23am UTC](https://discourse.vtk.org/t/vtk-use-file/3645 "2020-08-21T07:23:04Z")

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I just upgraded from VTK-8.1.2 to VTK-9.0.0 and am getting a new segmentation fault: \[2A4FCA\]vtkRayCastImageDisplayH:20 WARN| Error: no override found for ‘vtkRayCastImageDisplayHelper’. Segmentation fault: 11 The of…

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## [vtkPlaneWidget in Qt](https://discourse.vtk.org/t/vtkplanewidget-in-qt/3926)

<div class="topic-metadata">

**Author:** [@EvanLee](https://discourse.vtk.org/u/EvanLee)\
**Replies:** 3\
**Last updated:** [August 21, 2020, 5:22am UTC](https://discourse.vtk.org/t/vtkplanewidget-in-qt/3926 "2020-08-21T05:22:52Z")

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Hello，I added a vtkPlaneWidget to the qvtkwidget in Qt program, but it report some problem. Could anyone please give solution to me? Thanks

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## [Increase the 3D image dimension](https://discourse.vtk.org/t/increase-the-3d-image-dimension/4019)

<div class="topic-metadata">

**Author:** [@isuruwi](https://discourse.vtk.org/u/isuruwi)\
**Replies:** 4\
**Last updated:** [August 20, 2020, 4:30pm UTC](https://discourse.vtk.org/t/increase-the-3d-image-dimension/4019 "2020-08-20T16:30:31Z")

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I first created a volumetric mesh. Then extract the surface mesh using vtkGeometryFilter and use vtkPolyDataToImageStencil to generate the 3D image. I have got the image dimension as (200, 200, 320). But now I want to in…

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## [vtkSplineWidget2 not pickable or read only](https://discourse.vtk.org/t/vtksplinewidget2-not-pickable-or-read-only/4015)

<div class="topic-metadata">

**Author:** [@flaviu2](https://discourse.vtk.org/u/flaviu2)\
**Replies:** 1\
**Last updated:** [August 20, 2020, 3:58pm UTC](https://discourse.vtk.org/t/vtksplinewidget2-not-pickable-or-read-only/4015 "2020-08-20T15:58:07Z")

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Is there any method to setup vtkSplineWidget2 as not pickable ? I have tried following methods: pSplineRepresentation-\>DragableOff(); pSplineRepresentation-\>ClosedOff(); pSplineRepresentation-\>PickableOff(); However…

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## [installing vtk \> 8.2 for python 3.7.3 no attributes available](https://discourse.vtk.org/t/installing-vtk-8-2-for-python-3-7-3-no-attributes-available/3821)

<div class="topic-metadata">

**Author:** [@Kevin\_Johnson](https://discourse.vtk.org/u/Kevin_Johnson)\
**Replies:** 5\
**Last updated:** [August 20, 2020, 3:37pm UTC](https://discourse.vtk.org/t/installing-vtk-8-2-for-python-3-7-3-no-attributes-available/3821 "2020-08-20T15:37:45Z")

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I am trying to use VTK on a machine with ubuntu 16.04 and python 3.7.3 running Anaconda 2019.03. Anaconda installed vtk 8.2.0. I import vtk and type “vtk.” and the auto field only shows 9 options but is missing many im…

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## [Is it possible to change lines join type](https://discourse.vtk.org/t/is-it-possible-to-change-lines-join-type/4008)

<div class="topic-metadata">

**Author:** [@embeddedmz](https://discourse.vtk.org/u/embeddedmz)\
**Replies:** 2\
**Last updated:** [August 20, 2020, 8:12am UTC](https://discourse.vtk.org/t/is-it-possible-to-change-lines-join-type/4008 "2020-08-20T08:12:17Z")

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Hi everyone, The title says it all. Take this example : https://lorensen.github.io/VTKExamples/site/Cxx/GeometricObjects/PolyLine/ and insert this line of code after line 68 actor-\>GetProperty()-\>SetLineWidth(14); Bui…

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## [Multivolume Rendering Crashing (Python wrap, v8.2.0)](https://discourse.vtk.org/t/multivolume-rendering-crashing-python-wrap-v8-2-0/4028)

<div class="topic-metadata">

**Author:** [@yang613](https://discourse.vtk.org/u/yang613)\
**Replies:** 0\
**Last updated:** [August 19, 2020, 11:51pm UTC](https://discourse.vtk.org/t/multivolume-rendering-crashing-python-wrap-v8-2-0/4028 "2020-08-19T23:51:05Z")

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Hi everyone, I’m a beginner at VTK (using the Python wrapping) and am currently having a bug where the program silently crashes when vtk.vtkRenderWindow.Render() is called. Currently I’m running the following code on m…

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## [How to catch errors in VTK](https://discourse.vtk.org/t/how-to-catch-errors-in-vtk/1100)

<div class="topic-metadata">

**Author:** [@kit](https://discourse.vtk.org/u/kit)\
**Replies:** 6\
**Last updated:** [August 19, 2020, 9:48pm UTC](https://discourse.vtk.org/t/how-to-catch-errors-in-vtk/1100 "2020-08-19T21:48:09Z")

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Are there some examples / best practices for catching errors in VTK? The scenario I have is creating unit tests for a custom VTK filter, to make sure it catches cases where bad data is input, something like: vtkSmartPo…

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## [Using vtk.js in an angular app](https://discourse.vtk.org/t/using-vtk-js-in-an-angular-app/3909)

<div class="topic-metadata">

**Author:** [@Ramu](https://discourse.vtk.org/u/Ramu)\
**Replies:** 6\
**Last updated:** [August 19, 2020, 5:06pm UTC](https://discourse.vtk.org/t/using-vtk-js-in-an-angular-app/3909 "2020-08-19T17:06:45Z")

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I am using Geometry viewer in my angular app. I embedded the html page inside my application without any imports. I want to extend the viewer capabilities so I wish to use vtk.js and build things from scratch. I tried t…

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## [Checking if the rendering was successful](https://discourse.vtk.org/t/checking-if-the-rendering-was-successful/3999)

<div class="topic-metadata">

**Author:** [@mykolav](https://discourse.vtk.org/u/mykolav)\
**Replies:** 7\
**Last updated:** [August 19, 2020, 1:30pm UTC](https://discourse.vtk.org/t/checking-if-the-rendering-was-successful/3999 "2020-08-19T13:30:14Z")

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Hi, I’m trying to render a 3d volume. To catch error events I use ErrorObserver example. After the pipeline setup, I do ResetCamera() and Render(), but the return of the Render() function doesn’t guarantee that no error…

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## [How to associate a popup with a vtkActor?](https://discourse.vtk.org/t/how-to-associate-a-popup-with-a-vtkactor/3948)

<div class="topic-metadata">

**Author:** [@meihuisu](https://discourse.vtk.org/u/meihuisu)\
**Replies:** 9\
**Last updated:** [August 18, 2020, 10:03pm UTC](https://discourse.vtk.org/t/how-to-associate-a-popup-with-a-vtkactor/3948 "2020-08-18T22:03:12Z")

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I have several vtkActor(s) on a vktFullScreenRenderWindow that visualize faults in 3D space. I need to link a label popup with each actor but not sure how… thanks

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## [Pulling Range data from head instead of the calculated Range](https://discourse.vtk.org/t/pulling-range-data-from-head-instead-of-the-calculated-range/4013)

<div class="topic-metadata">

**Author:** [@samm-vs](https://discourse.vtk.org/u/samm-vs)\
**Replies:** 0\
**Last updated:** [August 18, 2020, 5:08pm UTC](https://discourse.vtk.org/t/pulling-range-data-from-head-instead-of-the-calculated-range/4013 "2020-08-18T17:08:15Z")

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Is there a way to select the range given by the meta-data for my scaler point array in vtk instead of pulling the calculated one from dataarray.getRange()? In another word how can I find the min and max of my dataset whi…

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## [How to get normal vectors on slices?](https://discourse.vtk.org/t/how-to-get-normal-vectors-on-slices/4011)

<div class="topic-metadata">

**Author:** [@Yusuf\_Demiroglu](https://discourse.vtk.org/u/Yusuf_Demiroglu)\
**Replies:** 0\
**Last updated:** [August 18, 2020, 11:21am UTC](https://discourse.vtk.org/t/how-to-get-normal-vectors-on-slices/4011 "2020-08-18T11:21:10Z")

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Hi everyone, I am trying to find forces on a slice that taken over a surface and the total closed area in this slice. I got some scalar quantities over the surface. I need normal vectors to be multiplied to get forces. …

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## [vtkRenderWindow only works in Load Event](https://discourse.vtk.org/t/vtkrenderwindow-only-works-in-load-event/4003)

<div class="topic-metadata">

**Author:** [@JimHewitt](https://discourse.vtk.org/u/JimHewitt)\
**Replies:** 4\
**Last updated:** [August 18, 2020, 4:11am UTC](https://discourse.vtk.org/t/vtkrenderwindow-only-works-in-load-event/4003 "2020-08-18T04:11:07Z")

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I’m trying the ReadPLY example and it works. However, when I move the call to Readply() from renderWindowControl1\_Load1 to a a button click event, it doesn’t work. Is there a way I can do this in the button click event…

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## [volume Render can't work well with shadeon in 'big' data(500 \* 1024 \* 1000 just 500mb)](https://discourse.vtk.org/t/volume-render-cant-work-well-with-shadeon-in-big-data-500-1024-1000-just-500mb/4006)

<div class="topic-metadata">

**Author:** [@kaia](https://discourse.vtk.org/u/kaia)\
**Replies:** 0\
**Last updated:** [August 18, 2020, 2:30am UTC](https://discourse.vtk.org/t/volume-render-cant-work-well-with-shadeon-in-big-data-500-1024-1000-just-500mb/4006 "2020-08-18T02:30:31Z")

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Hi VTK experts. I am experimenting with Volume Rendering in my VTK-based C# application, and I am facing some issues with the vtkVolumeProperty shadeon. and here is some fragments taken from code run 5001024500 is…

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## [PolydataMapper vs DataSetMapper](https://discourse.vtk.org/t/polydatamapper-vs-datasetmapper/3991)

<div class="topic-metadata">

**Author:** [@j-miguel](https://discourse.vtk.org/u/j-miguel)\
**Replies:** 2\
**Last updated:** [August 17, 2020, 4:49pm UTC](https://discourse.vtk.org/t/polydatamapper-vs-datasetmapper/3991 "2020-08-17T16:49:05Z")

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I’ve seen some examples using vtkDataSetMapper and others using vtkPolyDataMapper. (On a closer look to the vtkDataSetMapper implementation, I see that it actually creates a vtkPolyDataMapper and I noticed there is alre…

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