# Latest

**URL:** https://discourse.vtk.org/latest.md?page=197

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

**Page:** 198

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## [CombineImages - lots of OpenGL rendering messages.](https://discourse.vtk.org/t/combineimages-lots-of-opengl-rendering-messages/4385)

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**Author:** [@amaclean](https://discourse.vtk.org/u/amaclean)\
**Replies:** 1\
**Last updated:** [October 10, 2020, 9:55pm UTC](https://discourse.vtk.org/t/combineimages-lots-of-opengl-rendering-messages/4385 "2020-10-10T21:55:28Z")

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@ken-martin, You may have some ideas here. I have been updating the VTK Examples and this example produces a huge number of OpenGL generic warnings and errors: CombineImages. An image is finally produced. The test data…

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## [Warnings in VTK regarding number of points != zero](https://discourse.vtk.org/t/warnings-in-vtk-regarding-number-of-points-zero/4384)

<div class="topic-metadata">

**Author:** [@amaclean](https://discourse.vtk.org/u/amaclean)\
**Replies:** 3\
**Last updated:** [October 10, 2020, 9:50pm UTC](https://discourse.vtk.org/t/warnings-in-vtk-regarding-number-of-points-zero/4384 "2020-10-10T21:50:34Z")

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@Charles\_Gueunet, @mwestphal, any ideas regarding this? I have been modernising/updating the vtk examples and this example seems to be highlighting an inconsistency in VTK: ImageWarp. I remember many years ago translati…

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## [Test interaction](https://discourse.vtk.org/t/test-interaction/4223)

<div class="topic-metadata">

**Author:** [@aeslaughter](https://discourse.vtk.org/u/aeslaughter)\
**Replies:** 1\
**Last updated:** [October 9, 2020, 4:51pm UTC](https://discourse.vtk.org/t/test-interaction/4223 "2020-10-09T16:51:01Z")

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How can you simulate mouse and button presses correctly to test custom interaction? I would like to output an image, simulate mouse/buttons etc., then output another image so I can test that custom interaction commands …

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## [vtkSphereWidget2 in vtkGenericOpenGLRenderWindow](https://discourse.vtk.org/t/vtkspherewidget2-in-vtkgenericopenglrenderwindow/4379)

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**Author:** [@mallikarjun49](https://discourse.vtk.org/u/mallikarjun49)\
**Replies:** 5\
**Last updated:** [October 9, 2020, 5:02am UTC](https://discourse.vtk.org/t/vtkspherewidget2-in-vtkgenericopenglrenderwindow/4379 "2020-10-09T05:02:51Z")

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Hi, I am trying to use vtkGenericOpenGLRenderWindow instead of vtkRenderWindow in the example given for VtkSphereWidget2(https://lorensen.github.io/VTKExamples/site/Cxx/Widgets/SphereWidget2/) ,I don’t see any renderWin…

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## [VTK Build in ios OpenGL Error 1282](https://discourse.vtk.org/t/vtk-build-in-ios-opengl-error-1282/4304)

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**Author:** [@wonki](https://discourse.vtk.org/u/wonki)\
**Replies:** 3\
**Last updated:** [October 8, 2020, 5:52pm UTC](https://discourse.vtk.org/t/vtk-build-in-ios-opengl-error-1282/4304 "2020-10-08T17:52:16Z")

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Hello~ I’m freshman at researching volume rendering of medical data. I’m stuck at error of opengl long time… Help me please. Build VTK Tag 8.2 for ios by cmake. I set the build option like this VTK\_IOS\_BUILD to true …

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## [Increasing Line thickness for VTP](https://discourse.vtk.org/t/increasing-line-thickness-for-vtp/4378)

<div class="topic-metadata">

**Author:** [@samm-vs](https://discourse.vtk.org/u/samm-vs)\
**Replies:** 2\
**Last updated:** [October 8, 2020, 4:23pm UTC](https://discourse.vtk.org/t/increasing-line-thickness-for-vtp/4378 "2020-10-08T16:23:21Z")

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I am trying to make the lines of my VTP diagram thicker. I tried to use setLineWidth but from what I can read it only works with OpenGL render Windows form this link: Is there another way to do that? I just have a f…

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## [Blank image with vtkImageMapToColors, works in vtk8](https://discourse.vtk.org/t/blank-image-with-vtkimagemaptocolors-works-in-vtk8/4374)

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**Author:** [@Nil](https://discourse.vtk.org/u/Nil)\
**Replies:** 5\
**Last updated:** [October 8, 2020, 4:21pm UTC](https://discourse.vtk.org/t/blank-image-with-vtkimagemaptocolors-works-in-vtk8/4374 "2020-10-08T16:21:45Z")

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This code, based on the ImageMapToColors example, does what I want in vtk8, but it produces a blank image on vtk9. width = 15 height = 15 data = np.arange(width \* height, dtype='float32').reshape((width, height)) data\_…

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## [VTK uses hard-coded path to freetype.so resulting in failure of cross-compiling](https://discourse.vtk.org/t/vtk-uses-hard-coded-path-to-freetype-so-resulting-in-failure-of-cross-compiling/4377)

<div class="topic-metadata">

**Author:** [@left4taco](https://discourse.vtk.org/u/left4taco)\
**Replies:** 1\
**Last updated:** [October 8, 2020, 1:59pm UTC](https://discourse.vtk.org/t/vtk-uses-hard-coded-path-to-freetype-so-resulting-in-failure-of-cross-compiling/4377 "2020-10-08T13:59:19Z")

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Hi there. Recently we started using PCL in our application. Everything worked well on the x86\_64 side. Our next step is to cross-compile our application to aarch64 and this is where the problem raised. A little backgro…

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## [Proposal to add orientation to vtkImageData- Feedback Wanted](https://discourse.vtk.org/t/proposal-to-add-orientation-to-vtkimagedata-feedback-wanted/120)

<div class="topic-metadata">

**Author:** [@ken-martin](https://discourse.vtk.org/u/ken-martin)\
**Replies:** 46\
**Last updated:** [October 7, 2020, 3:53pm UTC](https://discourse.vtk.org/t/proposal-to-add-orientation-to-vtkimagedata-feedback-wanted/120 "2020-10-07T15:53:44Z")

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Summary: We are considering adding orientation into vtkImageData to support rotations and inversions but not shears. We are looking for feedback on the idea and the two approaches listed below. This document was created…

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## [Half border pixels in viewer](https://discourse.vtk.org/t/half-border-pixels-in-viewer/4371)

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**Author:** [@Nil](https://discourse.vtk.org/u/Nil)\
**Replies:** 1\
**Last updated:** [October 7, 2020, 3:27pm UTC](https://discourse.vtk.org/t/half-border-pixels-in-viewer/4371 "2020-10-07T15:27:45Z")

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Wanting to understand why there are thin/half border voxels in the viewer, I filled this bug report 3 months ago. Moreover, I just found the ImageMapToColors example which shows the same behavior. tl;dr as we can see in …

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## [Storing Meta data with a vtk file](https://discourse.vtk.org/t/storing-meta-data-with-a-vtk-file/4373)

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**Author:** [@jrwrigh](https://discourse.vtk.org/u/jrwrigh)\
**Replies:** 1\
**Last updated:** [October 7, 2020, 3:20pm UTC](https://discourse.vtk.org/t/storing-meta-data-with-a-vtk-file/4373 "2020-10-07T15:20:30Z")

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I’ve written a suite of tools that take in raw arrays of data from a file, combine it with an associated mesh, and then write out a vtk file. I’d like to write meta data to the output vtk file that says where the origina…

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## [vtk 9.0 hangs with visual c++2015 hanging in building code](https://discourse.vtk.org/t/vtk-9-0-hangs-with-visual-c-2015-hanging-in-building-code/4359)

<div class="topic-metadata">

**Author:** [@zandarina](https://discourse.vtk.org/u/zandarina)\
**Replies:** 7\
**Last updated:** [October 7, 2020, 7:48am UTC](https://discourse.vtk.org/t/vtk-9-0-hangs-with-visual-c-2015-hanging-in-building-code/4359 "2020-10-07T07:48:33Z")

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Hello, I have a doubt to upgrade my project to vtk 9.0. It was working all well with vtk 8.11. Then I compiled all in vtk 9 and itk 4 again. The build is correct and I changed the cmake of my project as: find\_package(…

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## [Is there any tools to find correspondence between two meshes in vtk?](https://discourse.vtk.org/t/is-there-any-tools-to-find-correspondence-between-two-meshes-in-vtk/4341)

<div class="topic-metadata">

**Author:** [@xiaozhi\_zhu](https://discourse.vtk.org/u/xiaozhi_zhu)\
**Replies:** 5\
**Last updated:** [October 6, 2020, 7:55pm UTC](https://discourse.vtk.org/t/is-there-any-tools-to-find-correspondence-between-two-meshes-in-vtk/4341 "2020-10-06T19:55:51Z")

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Hi everyone, I am a beginner in this area and hope to find some help here. Currently, I try to find a point-to-point correspondence between two meshes with each one being a 3D mesh of vascular. Two meshes are from diffe…

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## [Deleting vertices based on normal vector](https://discourse.vtk.org/t/deleting-vertices-based-on-normal-vector/4362)

<div class="topic-metadata">

**Author:** [@rjs44](https://discourse.vtk.org/u/rjs44)\
**Replies:** 5\
**Last updated:** [October 6, 2020, 6:26pm UTC](https://discourse.vtk.org/t/deleting-vertices-based-on-normal-vector/4362 "2020-10-06T18:26:09Z")

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I have a triangular mesh containing vertices that I would like to filter. I am able to filter based on the scalar values of the mean curvature, using vtkThreshold with Python3: curvatureFilter = vtk.vtkCurvatures() curv…

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## [vtk lighting problem when source inside an object](https://discourse.vtk.org/t/vtk-lighting-problem-when-source-inside-an-object/4329)

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**Author:** [@archimedes](https://discourse.vtk.org/u/archimedes)\
**Replies:** 3\
**Last updated:** [October 6, 2020, 5:49pm UTC](https://discourse.vtk.org/t/vtk-lighting-problem-when-source-inside-an-object/4329 "2020-10-06T17:49:00Z")

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On my Pythgon38 Windows10 platform, I am rejigging my solarsystem simulator from OpenGL to VTK. To illuminate the scene from the origin, I have placed a pair of 180deg coned spotlights back to back. With the help of co…

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## [Looking Glass Factory and Kitware: Desktop Holographic Displays Driven by VTK, ParaView, and 3D Slicer](https://discourse.vtk.org/t/looking-glass-factory-and-kitware-desktop-holographic-displays-driven-by-vtk-paraview-and-3d-slicer/4366)

<div class="topic-metadata">

**Author:** [@cory.quammen](https://discourse.vtk.org/u/cory.quammen)\
**Replies:** 0\
**Last updated:** [October 6, 2020, 5:15pm UTC](https://discourse.vtk.org/t/looking-glass-factory-and-kitware-desktop-holographic-displays-driven-by-vtk-paraview-and-3d-slicer/4366 "2020-10-06T17:15:27Z")

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Kitware has partnered with Looking Glass Factory (LGF), the global leader in the field of holographic interfaces, to add support for LGF’s holographic displays from any VTK-based application including ParaView, 3D Slicer,…

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## [vtkDistributedDataFilter hangs when used with SetMinimumGhostLevel to 1](https://discourse.vtk.org/t/vtkdistributeddatafilter-hangs-when-used-with-setminimumghostlevel-to-1/4364)

<div class="topic-metadata">

**Author:** [@myousefi2016](https://discourse.vtk.org/u/myousefi2016)\
**Replies:** 0\
**Last updated:** [October 6, 2020, 4:08pm UTC](https://discourse.vtk.org/t/vtkdistributeddatafilter-hangs-when-used-with-setminimumghostlevel-to-1/4364 "2020-10-06T16:08:51Z")

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I’m trying to distribute my vtkUnstructuredGrid objects that are in the order of 1 GB ~ 10 GB by using vtkDistributedDataFilter. It’s interesting that I don’t have any problem with small files by using the same pipeline …

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## [How to get the world coordinate along with a mouse cursor.](https://discourse.vtk.org/t/how-to-get-the-world-coordinate-along-with-a-mouse-cursor/4355)

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**Author:** [@Kim\_William](https://discourse.vtk.org/u/Kim_William)\
**Replies:** 0\
**Last updated:** [October 6, 2020, 1:01am UTC](https://discourse.vtk.org/t/how-to-get-the-world-coordinate-along-with-a-mouse-cursor/4355 "2020-10-06T01:01:04Z")

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Hi All. I have a question about how to get the world coordinate along with a mouse cursor. □ Background: I’m using the vtkRenderWindow to the Picture control on the MFC project. And I’m trying to get the world coordi…

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## [How to define a semitransparent mask instead of transparent](https://discourse.vtk.org/t/how-to-define-a-semitransparent-mask-instead-of-transparent/4330)

<div class="topic-metadata">

**Author:** [@zandarina](https://discourse.vtk.org/u/zandarina)\
**Replies:** 5\
**Last updated:** [October 5, 2020, 9:19am UTC](https://discourse.vtk.org/t/how-to-define-a-semitransparent-mask-instead-of-transparent/4330 "2020-10-05T09:19:24Z")

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Hello, I have a doubt. I have a volume and I add seeds to apply region growing and those areas selected become transparent by adding the mask in vtkGPUVolumeRayCastMapper. It works well. But I wonder if there is an opti…

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## [VTK Python: disappearing lines in the reslice tool](https://discourse.vtk.org/t/vtk-python-disappearing-lines-in-the-reslice-tool/4347)

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**Author:** [@Ennio\_Bolondi](https://discourse.vtk.org/u/Ennio_Bolondi)\
**Replies:** 0\
**Last updated:** [October 4, 2020, 9:14am UTC](https://discourse.vtk.org/t/vtk-python-disappearing-lines-in-the-reslice-tool/4347 "2020-10-04T09:14:26Z")

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Hi folks, I’m writing for pointing out an issue that I’m experiencing with Vtk Python. I’m working with the “reslice” tool and, as you can see in the image below, the line actors are hidden at the begin. They only app…

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## [Slice from vtkImagereslice has additional black edges](https://discourse.vtk.org/t/slice-from-vtkimagereslice-has-additional-black-edges/4333)

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**Author:** [@Amnesie](https://discourse.vtk.org/u/Amnesie)\
**Replies:** 13\
**Last updated:** [October 4, 2020, 10:42pm UTC](https://discourse.vtk.org/t/slice-from-vtkimagereslice-has-additional-black-edges/4333 "2020-10-04T22:42:16Z")

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Hi eveyone, I have a 3D-volume ,its size is as following: witdth:180mm,X height:100mm,Y depth:300 mm,Z it likes a fallen cuboid. At begining camera faces to xy-plane which means 180\*100 mm. Now I want to extract a…

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## [SSAO square artifacts & shimmer](https://discourse.vtk.org/t/ssao-square-artifacts-shimmer/4352)

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**Author:** [@fraseyboo](https://discourse.vtk.org/u/fraseyboo)\
**Replies:** 0\
**Last updated:** [October 4, 2020, 7:31pm UTC](https://discourse.vtk.org/t/ssao-square-artifacts-shimmer/4352 "2020-10-04T19:31:27Z")

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So I’m implementing some of the more advanced rendering techniques exposed with the release of VTK 9.0 and whilst a lot of the Physically Based Rendering works incredibly well I’m currently experiencing an issue with the…

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## [vtkMarchingCubes / vtkDiscreteMarchingCubes does not produce a closed mesh surface](https://discourse.vtk.org/t/vtkmarchingcubes-vtkdiscretemarchingcubes-does-not-produce-a-closed-mesh-surface/4312)

<div class="topic-metadata">

**Author:** [@bertikrueger](https://discourse.vtk.org/u/bertikrueger)\
**Replies:** 5\
**Last updated:** [October 4, 2020, 4:40am UTC](https://discourse.vtk.org/t/vtkmarchingcubes-vtkdiscretemarchingcubes-does-not-produce-a-closed-mesh-surface/4312 "2020-10-04T04:40:05Z")

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Hello Everyone. I have a simple three dimensional vtkImageData object representing a voxelgrid: If a voxel at an index (i, j, k) is set, the entry is 1 ( voxelImageData\[idx(x, y, z)\] = 1), if the voxel at this index …

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## [Extract polydata attributes 2D view/render/capture screenshot](https://discourse.vtk.org/t/extract-polydata-attributes-2d-view-render-capture-screenshot/4291)

<div class="topic-metadata">

**Author:** [@Juan\_C\_Prieto](https://discourse.vtk.org/u/Juan_C_Prieto)\
**Replies:** 2\
**Last updated:** [October 4, 2020, 4:00am UTC](https://discourse.vtk.org/t/extract-polydata-attributes-2d-view-render-capture-screenshot/4291 "2020-10-04T04:00:26Z")

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Hello, I am trying to extract polydata attributes and save them in 2D images. In other words, take an input mesh and generate renderings from different view points. I use the vtkCellLocator to find intersections using …

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## [3dConnexion (TDx) support in VTK on Windows?](https://discourse.vtk.org/t/3dconnexion-tdx-support-in-vtk-on-windows/1645)

<div class="topic-metadata">

**Author:** [@geoffw](https://discourse.vtk.org/u/geoffw)\
**Replies:** 5\
**Last updated:** [October 4, 2020, 2:37am UTC](https://discourse.vtk.org/t/3dconnexion-tdx-support-in-vtk-on-windows/1645 "2020-10-04T02:37:30Z")

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Hi, We are very interested in using 3DConnexion’s 3d mice in our software. I was excited to find that it was supported in vtk. However, looking at the build files, it seems perhaps it is not supported on windows. Settin…

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## [Questions about using vtkOpenGLHardwareSelector](https://discourse.vtk.org/t/questions-about-using-vtkopenglhardwareselector/4334)

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**Author:** [@geoffw](https://discourse.vtk.org/u/geoffw)\
**Replies:** 2\
**Last updated:** [October 4, 2020, 2:36am UTC](https://discourse.vtk.org/t/questions-about-using-vtkopenglhardwareselector/4334 "2020-10-04T02:36:05Z")

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Hi, We are using vtkOPenGLHardwareSelector as a base class for our own hardware cell picker. (While it seems like there are some hardware-accelerated prop pickers, we don’t see a hardware cell picker, so we wrote our ow…

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## [VTK 9.0 Offscreen Rendering](https://discourse.vtk.org/t/vtk-9-0-offscreen-rendering/3379)

<div class="topic-metadata">

**Author:** [@akaszynski](https://discourse.vtk.org/u/akaszynski)\
**Replies:** 1\
**Last updated:** [October 4, 2020, 1:31am UTC](https://discourse.vtk.org/t/vtk-9-0-offscreen-rendering/3379 "2020-10-04T01:31:49Z")

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Hello, I’m seeing a significant slowdown when rending offscreen with VTK 9.0: ren\_win.SetOffScreenRendering(1) The rendered image looks better than the ones from \<VTK9.0, however for testing purposes the renders are t…

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## [Move actor with keyboard arrow keys](https://discourse.vtk.org/t/move-actor-with-keyboard-arrow-keys/2045)

<div class="topic-metadata">

**Author:** [@rai-sam](https://discourse.vtk.org/u/rai-sam)\
**Replies:** 2\
**Last updated:** [October 3, 2020, 4:48pm UTC](https://discourse.vtk.org/t/move-actor-with-keyboard-arrow-keys/2045 "2020-10-03T16:48:02Z")

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How to move actor with keyboard arrow keys events? vtkInteractorStyleTrackballActor is not suitable. vtkInteractorStyleFlight is broken. I have implemented an observer with switch cases key codes VK\_LEFT, VK\_RIGHT, VK\_…

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## [Trying to render a series of dicom images belongs to MRI and Fluorescence but i am getting just white screen](https://discourse.vtk.org/t/trying-to-render-a-series-of-dicom-images-belongs-to-mri-and-fluorescence-but-i-am-getting-just-white-screen/4338)

<div class="topic-metadata">

**Author:** [@Yuvi-416](https://discourse.vtk.org/u/Yuvi-416)\
**Replies:** 9\
**Last updated:** [October 3, 2020, 12:42pm UTC](https://discourse.vtk.org/t/trying-to-render-a-series-of-dicom-images-belongs-to-mri-and-fluorescence-but-i-am-getting-just-white-screen/4338 "2020-10-03T12:42:11Z")

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Hello there, I wrote a simple program to render a series of dicom images and it shows a good result for a CT images (exp: CT.dcm) but when i run the same code for series of MRI (MRI.dcm) or Fluorescence (F.dcm) images, …

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## [Project build fails when CUDA compiler is used](https://discourse.vtk.org/t/project-build-fails-when-cuda-compiler-is-used/4342)

<div class="topic-metadata">

**Author:** [@McDave17](https://discourse.vtk.org/u/McDave17)\
**Replies:** 0\
**Last updated:** [October 3, 2020, 9:33am UTC](https://discourse.vtk.org/t/project-build-fails-when-cuda-compiler-is-used/4342 "2020-10-03T09:33:22Z")

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Hello, When I try to compile my Qt/VTK project with CUDA enabled I get following errors. VTK has enabled VTKm modules, both VTK and VTK-m are on the most recent master-commit. VTK: 84a585724586b265065f6c47332c4b928e31…

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