# Latest

**URL:** https://discourse.vtk.org/latest.md?page=252

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

**Page:** 253

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## [Mark area in display space](https://discourse.vtk.org/t/mark-area-in-display-space/760)

<div class="topic-metadata">

**Author:** [@pettaa123](https://discourse.vtk.org/u/pettaa123)\
**Replies:** 0\
**Last updated:** [April 15, 2019, 1:44pm UTC](https://discourse.vtk.org/t/mark-area-in-display-space/760 "2019-04-15T13:44:54Z")

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Any suggestions how to draw a rectangle or circle into display space, in order to mark an area in my 3D rendered scene? Something like this

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## [Permanent smooth Rotation of actors](https://discourse.vtk.org/t/permanent-smooth-rotation-of-actors/670)

<div class="topic-metadata">

**Author:** [@pettaa123](https://discourse.vtk.org/u/pettaa123)\
**Replies:** 4\
**Last updated:** [April 15, 2019, 12:09pm UTC](https://discourse.vtk.org/t/permanent-smooth-rotation-of-actors/670 "2019-04-15T12:09:59Z")

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I would like to add smooth permanent Rotation to some actors. Is there an Example on how to achieve this? I think I could listen to a Rendered Event

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## [How to find the main axis normal of a vtkCylinderSource?](https://discourse.vtk.org/t/how-to-find-the-main-axis-normal-of-a-vtkcylindersource/722)

<div class="topic-metadata">

**Author:** [@siaeleni](https://discourse.vtk.org/u/siaeleni)\
**Replies:** 5\
**Last updated:** [April 15, 2019, 6:59am UTC](https://discourse.vtk.org/t/how-to-find-the-main-axis-normal-of-a-vtkcylindersource/722 "2019-04-15T06:59:54Z")

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Hello, I was wondering how can I get the main axis as a vector of the vtkCylinderSource? Any help is really appreciated.

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## [Trying to write VTU files from fortran](https://discourse.vtk.org/t/trying-to-write-vtu-files-from-fortran/470)

<div class="topic-metadata">

**Author:** [@vrkssai](https://discourse.vtk.org/u/vrkssai)\
**Replies:** 4\
**Last updated:** [April 14, 2019, 4:26pm UTC](https://discourse.vtk.org/t/trying-to-write-vtu-files-from-fortran/470 "2019-04-14T16:26:20Z")

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I’m trying to write a VTU file in fortran. I had prior experience writing binary vtk legacy files using fortran, I’m using the same logic to write the VTU files. But the binary files byte order seems to be a problem, bec…

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## [Error while enabling the vtkDICOM module in VTK 8.2.0](https://discourse.vtk.org/t/error-while-enabling-the-vtkdicom-module-in-vtk-8-2-0/753)

<div class="topic-metadata">

**Author:** [@chenjianyyzz](https://discourse.vtk.org/u/chenjianyyzz)\
**Replies:** 0\
**Last updated:** [April 13, 2019, 1:07am UTC](https://discourse.vtk.org/t/error-while-enabling-the-vtkdicom-module-in-vtk-8-2-0/753 "2019-04-13T01:07:34Z")

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I try to enable the vtkDICOM module in VTK 8.2.0, I set the Module vtkDICOM option for the cmake cache: cmake -D Module\_vtkDICOM :BOOL=ON …/vtk -source then I got the warning: CMake Warning: \*\* Manually-specifi…

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## [Error with inserting vertex cells](https://discourse.vtk.org/t/error-with-inserting-vertex-cells/750)

<div class="topic-metadata">

**Author:** [@Frank](https://discourse.vtk.org/u/Frank)\
**Replies:** 2\
**Last updated:** [April 12, 2019, 1:56pm UTC](https://discourse.vtk.org/t/error-with-inserting-vertex-cells/750 "2019-04-12T13:56:38Z")

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I want to create a polyData with lots of vertex. So I followed example auto vertexes = vtkSmartPointer\<vtkCellArray\>::New(); for (int i = 0; i \< data-\>GetNumberOfPoints(); i++) { auto vertex = vtkSmartPointer\<vtkVer…

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## [Building VTK for Arm64 with OpenGL ES](https://discourse.vtk.org/t/building-vtk-for-arm64-with-opengl-es/707)

<div class="topic-metadata">

**Author:** [@adamrankin](https://discourse.vtk.org/u/adamrankin)\
**Replies:** 5\
**Last updated:** [April 12, 2019, 1:31pm UTC](https://discourse.vtk.org/t/building-vtk-for-arm64-with-opengl-es/707 "2019-04-12T13:31:58Z")

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Hello, I am trying to build VTK on FriendlyDesktop (Ubuntu flavour) on my NanoPC-T4, and am running into a build error. /home/pi/devel/PB-x64/Deps/vtk/GUISupport/Qt/QVTKOpenGLNativeWidget.cxx: In member function ‘virtu…

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## [VTK 8.2.0 + Qt 5.12.2 weird event queue processing](https://discourse.vtk.org/t/vtk-8-2-0-qt-5-12-2-weird-event-queue-processing/740)

<div class="topic-metadata">

**Author:** [@Andrei\_Ivanov](https://discourse.vtk.org/u/Andrei_Ivanov)\
**Replies:** 5\
**Last updated:** [April 12, 2019, 12:41pm UTC](https://discourse.vtk.org/t/vtk-8-2-0-qt-5-12-2-weird-event-queue-processing/740 "2019-04-12T12:41:35Z")

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Dear all! I installed VTK 8.2.0 + Qt 5.12.2 and noticed a weird behavior: all my Qt programs that previously was working now crash at the moment of vtkRenderer creation if I build them in -DCMAKE\_BUILD\_TYPE=Release. I…

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## [Dynamically change position of Axes](https://discourse.vtk.org/t/dynamically-change-position-of-axes/691)

<div class="topic-metadata">

**Author:** [@fern17](https://discourse.vtk.org/u/fern17)\
**Replies:** 1\
**Last updated:** [April 12, 2019, 10:51am UTC](https://discourse.vtk.org/t/dynamically-change-position-of-axes/691 "2019-04-12T10:51:04Z")

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Hello. I’m trying to control the position of the Axes (vtkOrientationMarkerWidget). In our interface, there should be an option to change the position with 4 possible values: Bottom left, bottom right, top left, top ri…

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## [how to apply CT Presets and LUT simultaneously using vtkimageviewer2](https://discourse.vtk.org/t/how-to-apply-ct-presets-and-lut-simultaneously-using-vtkimageviewer2/726)

<div class="topic-metadata">

**Author:** [@Aravind](https://discourse.vtk.org/u/Aravind)\
**Replies:** 0\
**Last updated:** [April 10, 2019, 9:09am UTC](https://discourse.vtk.org/t/how-to-apply-ct-presets-and-lut-simultaneously-using-vtkimageviewer2/726 "2019-04-10T09:09:29Z")

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Hello - I am building an application where by I have the options to apply LUT as well as CT Presets. I am using vtkimageviewer2 for rendering the slices and I am using a nii image reader. Not sure if what I am doing is…

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## [vtkImageMapper + vtkActor2D show up as black](https://discourse.vtk.org/t/vtkimagemapper-vtkactor2d-show-up-as-black/744)

<div class="topic-metadata">

**Author:** [@estan](https://discourse.vtk.org/u/estan)\
**Replies:** 1\
**Last updated:** [April 12, 2019, 9:25am UTC](https://discourse.vtk.org/t/vtkimagemapper-vtkactor2d-show-up-as-black/744 "2019-04-12T09:25:46Z")

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Hi all, I’m struggling with getting a vtkImageMapper + vtkActor2D to show up correctly. It’s showing up in black when I expect it to be all red. Test Case #!/usr/bin/env python from vtk import ( vtkImageData, …

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## [Lighting update on camera position reset](https://discourse.vtk.org/t/lighting-update-on-camera-position-reset/629)

<div class="topic-metadata">

**Author:** [@Marco](https://discourse.vtk.org/u/Marco)\
**Replies:** 6\
**Last updated:** [April 11, 2019, 7:04pm UTC](https://discourse.vtk.org/t/lighting-update-on-camera-position-reset/629 "2019-04-11T19:04:13Z")

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Hi all. In my Java-based, VTK-based application, I am working on the implementation of volume rendering functionalities. I am working with the latest VTK 8.2. All is working pretty well at the moment: I can generate an…

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## [vtkGlyph3DMapper::ScaleMode: mismatch between header and source files](https://discourse.vtk.org/t/vtkglyph3dmapper-mismatch-between-header-and-source-files/741)

<div class="topic-metadata">

**Author:** [@Haocheng\_Liu](https://discourse.vtk.org/u/Haocheng_Liu)\
**Replies:** 2\
**Last updated:** [April 11, 2019, 7:00pm UTC](https://discourse.vtk.org/t/vtkglyph3dmapper-mismatch-between-header-and-source-files/741 "2019-04-11T19:00:59Z")

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vtkGlyph3DMapper header states that the default ScaleMode is NO\_DATA\_SCALING. However in the source file, it’s set to SCALE\_BY\_MAGNITUDE. Question: What should be the right default settings here? ParaView seems is abl…

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## [Calculate Volume of Quadratic Tetrahedron](https://discourse.vtk.org/t/calculate-volume-of-quadratic-tetrahedron/728)

<div class="topic-metadata">

**Author:** [@alx](https://discourse.vtk.org/u/alx)\
**Replies:** 4\
**Last updated:** [April 11, 2019, 4:09pm UTC](https://discourse.vtk.org/t/calculate-volume-of-quadratic-tetrahedron/728 "2019-04-11T16:09:50Z")

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I have an unstructured mesh of quadratic tetrahedrons. I would like to calculate the volume of each cell, but I am only able to calculate the volume of a linear tetrahedron using vtk.vtkMeshQuality.TetVolume(cell). Is t…

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## [Subpixel edge detection with local surface fitting to maximum gradient](https://discourse.vtk.org/t/subpixel-edge-detection-with-local-surface-fitting-to-maximum-gradient/718)

<div class="topic-metadata">

**Author:** [@madcting](https://discourse.vtk.org/u/madcting)\
**Replies:** 8\
**Last updated:** [April 11, 2019, 3:51pm UTC](https://discourse.vtk.org/t/subpixel-edge-detection-with-local-surface-fitting-to-maximum-gradient/718 "2019-04-11T15:51:53Z")

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Dear all, I’m new to vtk. I’m wondering if there’s already a solutions for extracting surfaces from CT dataset, with subpixel precision. Tools such as Slicer, FIJI and OpenIA uses marching cubes or flying edges for cr…

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## [How to evaluate if I'd benefit from using Intel TBB with VTK?](https://discourse.vtk.org/t/how-to-evaluate-if-id-benefit-from-using-intel-tbb-with-vtk/736)

<div class="topic-metadata">

**Author:** [@seanm](https://discourse.vtk.org/u/seanm)\
**Replies:** 7\
**Last updated:** [April 11, 2019, 2:55pm UTC](https://discourse.vtk.org/t/how-to-evaluate-if-id-benefit-from-using-intel-tbb-with-vtk/736 "2019-04-11T14:55:46Z")

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Hi all, How can I evaluate if I’d benefit from using Intel TBB with VTK? That is, is there a list of VTK classes that use it? Or is there some TBB bottleneck function that I could put a breakpoint on to see if my app’…

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## [Volume rendering with shading on : light orientation issue when user matrix has been modified](https://discourse.vtk.org/t/volume-rendering-with-shading-on-light-orientation-issue-when-user-matrix-has-been-modified/715)

<div class="topic-metadata">

**Author:** [@renaud-lebrun](https://discourse.vtk.org/u/renaud-lebrun)\
**Replies:** 13\
**Last updated:** [April 11, 2019, 9:38am UTC](https://discourse.vtk.org/t/volume-rendering-with-shading-on-light-orientation-issue-when-user-matrix-has-been-modified/715 "2019-04-11T09:38:17Z")

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Dear All, I have a question regarding volume mapper shading related with light orientation. I develop a VTK based application ( https://github.com/morphomuseum/MorphoDig ), in which I use 3D rendering of a 3D volume w…

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## [VTKjs: Compressing Textures?](https://discourse.vtk.org/t/vtkjs-compressing-textures/734)

<div class="topic-metadata">

**Author:** [@banesullivan](https://discourse.vtk.org/u/banesullivan)\
**Replies:** 3\
**Last updated:** [April 10, 2019, 6:21pm UTC](https://discourse.vtk.org/t/vtkjs-compressing-textures/734 "2019-04-10T18:21:51Z")

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I’m curious if there is a way to further compress textures associated with actors when using the ParaView VTKjs export script found here. Please note that I have heavily modified this script for exporting vtki rendering …

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## [Different positions between vtkPolyDataMapper2D and vtkPolyDataMapper](https://discourse.vtk.org/t/different-positions-between-vtkpolydatamapper2d-and-vtkpolydatamapper/732)

<div class="topic-metadata">

**Author:** [@zandarina](https://discourse.vtk.org/u/zandarina)\
**Replies:** 0\
**Last updated:** [April 10, 2019, 4:05pm UTC](https://discourse.vtk.org/t/different-positions-between-vtkpolydatamapper2d-and-vtkpolydatamapper/732 "2019-04-10T16:05:19Z")

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Hi I have a spline and i want to transform it in polydata. If i do it in 3d it works perfect but then i use the viewer, it only renders it in the slice corresponding to its z. And i want to have it in every slice. To do…

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## [VTK 8.2 10 bit color monitor support](https://discourse.vtk.org/t/vtk-8-2-10-bit-color-monitor-support/731)

<div class="topic-metadata">

**Author:** [@davidu](https://discourse.vtk.org/u/davidu)\
**Replies:** 0\
**Last updated:** [April 10, 2019, 3:07pm UTC](https://discourse.vtk.org/t/vtk-8-2-10-bit-color-monitor-support/731 "2019-04-10T15:07:27Z")

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Dear community. I have searched all over to look if support for 10 bit displays is built in. I saw it was in a wish list some distributions before…

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## [Rendering/OSPRay to be renamed Rendering/RayTracing in VTK 9.0](https://discourse.vtk.org/t/rendering-ospray-to-be-renamed-rendering-raytracing-in-vtk-9-0/720)

<div class="topic-metadata">

**Author:** [@Dave\_DeMarle](https://discourse.vtk.org/u/Dave_DeMarle)\
**Replies:** 1\
**Last updated:** [April 10, 2019, 9:18am UTC](https://discourse.vtk.org/t/rendering-ospray-to-be-renamed-rendering-raytracing-in-vtk-9-0/720 "2019-04-10T09:18:50Z")

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Hey folks, Just a heads up that starting with VTK master as of Yesterday, the OptiX rendering module has been removed and the OSPRay module has been renamed RayTracing, which is now capable of using both back ends. The …

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## [Intersect polydata with an implicit function](https://discourse.vtk.org/t/intersect-polydata-with-an-implicit-function/706)

<div class="topic-metadata">

**Author:** [@lmainguy](https://discourse.vtk.org/u/lmainguy)\
**Replies:** 9\
**Last updated:** [April 9, 2019, 9:24pm UTC](https://discourse.vtk.org/t/intersect-polydata-with-an-implicit-function/706 "2019-04-09T21:24:42Z")

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Hi all, There is vtkIntersectionPolyDataFilter to get the intersection of two polydata but I didn’t find a filter that could that with a polydata and an implicit function. Of course, one can convert an implicit functio…

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## [Get PointID with PointPicker in Polydata](https://discourse.vtk.org/t/get-pointid-with-pointpicker-in-polydata/713)

<div class="topic-metadata">

**Author:** [@Thomas](https://discourse.vtk.org/u/Thomas)\
**Replies:** 1\
**Last updated:** [April 9, 2019, 7:01pm UTC](https://discourse.vtk.org/t/get-pointid-with-pointpicker-in-polydata/713 "2019-04-09T19:01:06Z")

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Hi everybody, I currently have some problems concerning the pointPicker in vtk. I have a dataset in polydata, which I visualize as points in a qvtk-widget as part of a qt-framework. Here, I define: // point Picker (pi…

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## [How to write STL from x y z co-ordinates ?](https://discourse.vtk.org/t/how-to-write-stl-from-x-y-z-co-ordinates/711)

<div class="topic-metadata">

**Author:** [@selvakarna](https://discourse.vtk.org/u/selvakarna)\
**Replies:** 3\
**Last updated:** [April 9, 2019, 2:27pm UTC](https://discourse.vtk.org/t/how-to-write-stl-from-x-y-z-co-ordinates/711 "2019-04-09T14:27:15Z")

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How to write STL from x y z co-ordinates? x y z are extracted from 3D volume images, so my goal is x y z convert to STL?

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## [Python VTK -- Can we get the mesh rendered from the colorized point cloud](https://discourse.vtk.org/t/python-vtk-can-we-get-the-mesh-rendered-from-the-colorized-point-cloud/200)

<div class="topic-metadata">

**Author:** [@ljc19800331](https://discourse.vtk.org/u/ljc19800331)\
**Replies:** 17\
**Last updated:** [April 9, 2019, 7:37am UTC](https://discourse.vtk.org/t/python-vtk-can-we-get-the-mesh-rendered-from-the-colorized-point-cloud/200 "2019-04-09T07:37:25Z")

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Hello, I am going to capture different images from different viewpoint pose of virtual camera in Python VTK. When I set a close viewpoint to the point cloud, the point cloud became sparse and I could not get a good imag…

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## [vtkpython 3.7 error with windows debug build](https://discourse.vtk.org/t/vtkpython-3-7-error-with-windows-debug-build/692)

<div class="topic-metadata">

**Author:** [@Aron\_Helser](https://discourse.vtk.org/u/Aron_Helser)\
**Replies:** 8\
**Last updated:** [April 8, 2019, 3:11pm UTC](https://discourse.vtk.org/t/vtkpython-3-7-error-with-windows-debug-build/692 "2019-04-08T15:11:27Z")

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I’m seeing an error when trying to use vtkpython with python 3.7 and a debug build: Python 3.7.3 (v3.7.3:ef4ec6ed12, Mar 25 2019, 22:22:05) \[MSC v.1916 64 bit (AMD64)\] on win32 Type “help”, “copyright”, “credits” or “l…

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## [Git LFS error checking out VTKExamples](https://discourse.vtk.org/t/git-lfs-error-checking-out-vtkexamples/650)

<div class="topic-metadata">

**Author:** [@Aron\_Helser](https://discourse.vtk.org/u/Aron_Helser)\
**Replies:** 3\
**Last updated:** [April 8, 2019, 12:55pm UTC](https://discourse.vtk.org/t/git-lfs-error-checking-out-vtkexamples/650 "2019-04-08T12:55:12Z")

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I’m having a problem checking out the VTKExamples repo right now. It gives me a git LFS error, on a fresh clone or a pull: Downloading src/Testing/Data/Frog/frog.mhd (304 B) Error downloading object: src/Testing/Data/F…

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## [Is there a "slice(s) of pie" filter in VTK?](https://discourse.vtk.org/t/is-there-a-slice-s-of-pie-filter-in-vtk/695)

<div class="topic-metadata">

**Author:** [@dlrdave](https://discourse.vtk.org/u/dlrdave)\
**Replies:** 3\
**Last updated:** [April 7, 2019, 10:36pm UTC](https://discourse.vtk.org/t/is-there-a-slice-s-of-pie-filter-in-vtk/695 "2019-04-07T22:36:31Z")

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I have a cylinder that bounds a polygonal data set: all of the points and cells in the data set are inside the cylinder. I would like to extract regions of the cylinder that are shaped like pieces of pie. I’d use the the…

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## [Vtkprobefilter or vtkreslicer](https://discourse.vtk.org/t/vtkprobefilter-or-vtkreslicer/689)

<div class="topic-metadata">

**Author:** [@zandarina](https://discourse.vtk.org/u/zandarina)\
**Replies:** 0\
**Last updated:** [April 4, 2019, 8:42pm UTC](https://discourse.vtk.org/t/vtkprobefilter-or-vtkreslicer/689 "2019-04-04T20:42:44Z")

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Dear all I want to reslice a 3d volume according to a curve. I compute the perpendicular every 2 points of the curve and i get this slice in the center position on the point of the curve. I am using vtkreslice filter a…

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## [vtkimagereslice does not work when i define z](https://discourse.vtk.org/t/vtkimagereslice-does-not-work-when-i-define-z/699)

<div class="topic-metadata">

**Author:** [@zandarina](https://discourse.vtk.org/u/zandarina)\
**Replies:** 0\
**Last updated:** [April 7, 2019, 2:43pm UTC](https://discourse.vtk.org/t/vtkimagereslice-does-not-work-when-i-define-z/699 "2019-04-07T14:43:31Z")

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I want to get slices from a volume along a curve with points with vtkimagereslice and get a slice centered in each point and the orientation according to the orientation of these 2 points. The problem is when i define th…

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