# Support

**URL:** https://discourse.vtk.org/c/support/6.md?page=160

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

**Page:** 161

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## [Modifying scalar bar value labels](https://discourse.vtk.org/t/modifying-scalar-bar-value-labels/468)

<div class="topic-metadata">

**Author:** [@dbonhaus](https://discourse.vtk.org/u/dbonhaus)\
**Replies:** 1\
**Last updated:** [March 27, 2019, 1:28pm UTC](https://discourse.vtk.org/t/modifying-scalar-bar-value-labels/468 "2019-03-27T13:28:21Z")

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I need to apply a unit conversion to the numeric labels displayed with the scalar bar. I tried subclassing the scalar bar actor and overriding the EditAnnotations method, but there are no annotations to edit when the met…

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## [Update time step of a filter having multiple inputs on one of its ports](https://discourse.vtk.org/t/update-time-step-of-a-filter-having-multiple-inputs-on-one-of-its-ports/615)

<div class="topic-metadata">

**Author:** [@embeddedmz](https://discourse.vtk.org/u/embeddedmz)\
**Replies:** 0\
**Last updated:** [March 27, 2019, 11:58am UTC](https://discourse.vtk.org/t/update-time-step-of-a-filter-having-multiple-inputs-on-one-of-its-ports/615 "2019-03-27T11:58:59Z")

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Hello, Is there someone who can tell me why UPDATE\_TIME\_STEP of a port connection of a filter is not an epoch anymore when this last has a repeatable input (info-\>Set(vtkAlgorithm::INPUT\_IS\_REPEATABLE(), 1); ) but rath…

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## [vtkResliceImageViewer do not recognize the slice in z build from append from reslice](https://discourse.vtk.org/t/vtkresliceimageviewer-do-not-recognize-the-slice-in-z-build-from-append-from-reslice/608)

<div class="topic-metadata">

**Author:** [@zandarina](https://discourse.vtk.org/u/zandarina)\
**Replies:** 1\
**Last updated:** [March 26, 2019, 4:56pm UTC](https://discourse.vtk.org/t/vtkresliceimageviewer-do-not-recognize-the-slice-in-z-build-from-append-from-reslice/608 "2019-03-26T16:56:19Z")

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Dear all, I have a question. I want to show using vtkResliceImageViewer the slices i have got from the reslicer filter. So i append in z the output and i call a fuction to show me the vtkImageData withh all the…

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## [Error building 8.2.0 on macOS Mojave](https://discourse.vtk.org/t/error-building-8-2-0-on-macos-mojave/604)

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**Author:** [@langer](https://discourse.vtk.org/u/langer)\
**Replies:** 0\
**Last updated:** [March 25, 2019, 9:02pm UTC](https://discourse.vtk.org/t/error-building-8-2-0-on-macos-mojave/604 "2019-03-25T21:02:19Z")

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Hi – When building VTK 8.2.0 on macOS Mojave, configured with VTK\_USE\_X=ON and VTK\_USE\_COCOA=OFF, I get this error: \[ 42%\] Linking CXX shared library ../../lib/libvtkRenderingOpenGL2-8.2.dylib Undefined symbols for a…

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## [ModuleNotFoundError: No module named 'vtkCommonKitPython'](https://discourse.vtk.org/t/modulenotfounderror-no-module-named-vtkcommonkitpython/595)

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**Author:** [@mat](https://discourse.vtk.org/u/mat)\
**Replies:** 2\
**Last updated:** [March 25, 2019, 12:46pm UTC](https://discourse.vtk.org/t/modulenotfounderror-no-module-named-vtkcommonkitpython/595 "2019-03-25T12:46:30Z")

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Hello all, On a windows 7 64 bits computer, I installed pyhton 3.7.1. then in a command prompt I installed vtk with the command: pip3 install vtk This instaled vtk correctly as far as I can tell. But then in pytho…

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## [how to filter points within polygon on 3d data in any view](https://discourse.vtk.org/t/how-to-filter-points-within-polygon-on-3d-data-in-any-view/600)

<div class="topic-metadata">

**Author:** [@kondreti](https://discourse.vtk.org/u/kondreti)\
**Replies:** 0\
**Last updated:** [March 25, 2019, 11:39am UTC](https://discourse.vtk.org/t/how-to-filter-points-within-polygon-on-3d-data-in-any-view/600 "2019-03-25T11:39:35Z")

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filter points within polygon on 3d data

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## [Multiple .VTR files](https://discourse.vtk.org/t/multiple-vtr-files/586)

<div class="topic-metadata">

**Author:** [@S97](https://discourse.vtk.org/u/S97)\
**Replies:** 4\
**Last updated:** [March 21, 2019, 11:09pm UTC](https://discourse.vtk.org/t/multiple-vtr-files/586 "2019-03-21T23:09:32Z")

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Hello, I am after some guidance on where to go with my project… I currently have a python pre processing file that reads a netCDF and generates a .vtr rectilinear grid which I then read in, to another python vtk file w…

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## [Use VTK python with several CPUs](https://discourse.vtk.org/t/use-vtk-python-with-several-cpus/591)

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**Author:** [@quentin\_douasbin](https://discourse.vtk.org/u/quentin_douasbin)\
**Replies:** 0\
**Last updated:** [March 21, 2019, 10:07pm UTC](https://discourse.vtk.org/t/use-vtk-python-with-several-cpus/591 "2019-03-21T22:07:17Z")

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Hi, I am using the vtk python module. It is awesome and I love it. I use VTK as a postprocessing tool for computing gradients of vector quantities in large unstructured meshes (typically tens of million cells). I heard…

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## [Intersect (vertical) line segment with triangulated surface (topo)](https://discourse.vtk.org/t/intersect-vertical-line-segment-with-triangulated-surface-topo/547)

<div class="topic-metadata">

**Author:** [@cobo](https://discourse.vtk.org/u/cobo)\
**Replies:** 3\
**Last updated:** [March 21, 2019, 4:17pm UTC](https://discourse.vtk.org/t/intersect-vertical-line-segment-with-triangulated-surface-topo/547 "2019-03-21T16:17:20Z")

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What I want to achieve: I have a topo surface (triangulated, “2.5D” type) and a point, and I want to find the relative position of the point to that topo: is it outside the boundary of the topo or inside? if it is insi…

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## [Memory problem when reading large files](https://discourse.vtk.org/t/memory-problem-when-reading-large-files/511)

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**Author:** [@Oleg](https://discourse.vtk.org/u/Oleg)\
**Replies:** 9\
**Last updated:** [March 21, 2019, 4:02pm UTC](https://discourse.vtk.org/t/memory-problem-when-reading-large-files/511 "2019-03-21T16:02:02Z")

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I have a certain problem reading large files that previously have been generated in a vtk application (VTK-7.1.1 64 bits). In this particular case I generated a model with 100 million points in double precision and a sca…

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## [Multiple viewport interact problem on Mac python](https://discourse.vtk.org/t/multiple-viewport-interact-problem-on-mac-python/584)

<div class="topic-metadata">

**Author:** [@artzers](https://discourse.vtk.org/u/artzers)\
**Replies:** 0\
**Last updated:** [March 21, 2019, 2:34pm UTC](https://discourse.vtk.org/t/multiple-viewport-interact-problem-on-mac-python/584 "2019-03-21T14:34:22Z")

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Hi, I use python-VTK and pythonQT5 to build multiple viewport application. On windows, everything is OK. I can interact with vtk actor in corresponding viewport due to the mouse cursor position. But on Mac, I can just i…

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## [mouse coordinates from a 3d volume with wrong y](https://discourse.vtk.org/t/mouse-coordinates-from-a-3d-volume-with-wrong-y/543)

<div class="topic-metadata">

**Author:** [@zandarina](https://discourse.vtk.org/u/zandarina)\
**Replies:** 1\
**Last updated:** [March 20, 2019, 3:24pm UTC](https://discourse.vtk.org/t/mouse-coordinates-from-a-3d-volume-with-wrong-y/543 "2019-03-20T15:24:06Z")

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Dear all, I want to get the positions of a volume using the mouse for segmentation. But the y coordinate is wrong. I only get the x and z fine but the depth (y) is not correct. I use this code to get the position. Is t…

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## [No mode name 'VtkRendingQt' on Mac mini](https://discourse.vtk.org/t/no-mode-name-vtkrendingqt-on-mac-mini/513)

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**Author:** [@fqzhice](https://discourse.vtk.org/u/fqzhice)\
**Replies:** 4\
**Last updated:** [March 19, 2019, 6:24pm UTC](https://discourse.vtk.org/t/no-mode-name-vtkrendingqt-on-mac-mini/513 "2019-03-19T18:24:22Z")

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In terminal, it occurs when run python3 and import vtk after compiling VTK 8.2 branch in Mac mini and run ‘make install’. configure: MacOS: Mojave, Mac mini(2018), Graphic Card:Intel UHD Graphics 630 1536MB Python 3.…

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## [theora in VTK 8.2.0 produces an error](https://discourse.vtk.org/t/theora-in-vtk-8-2-0-produces-an-error/515)

<div class="topic-metadata">

**Author:** [@Kenta\_Kabashima](https://discourse.vtk.org/u/Kenta_Kabashima)\
**Replies:** 1\
**Last updated:** [March 19, 2019, 6:23pm UTC](https://discourse.vtk.org/t/theora-in-vtk-8-2-0-produces-an-error/515 "2019-03-19T18:23:11Z")

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I’m using VTK 8.2.0 with Visual Studio 2017. When using debug build of VTK, an error about use of an uninitialized variable was detected at line 326 in “ThirdParty\\theora\\vtktheora\\lib\\analyze.c” as follows: static voi…

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## [Compile vtk-master fails in Mac mini 2018](https://discourse.vtk.org/t/compile-vtk-master-fails-in-mac-mini-2018/517)

<div class="topic-metadata">

**Author:** [@fqzhice](https://discourse.vtk.org/u/fqzhice)\
**Replies:** 1\
**Last updated:** [March 19, 2019, 6:21pm UTC](https://discourse.vtk.org/t/compile-vtk-master-fails-in-mac-mini-2018/517 "2019-03-19T18:21:27Z")

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python 3.6 Qt5.11

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## [visualize axial,coronal and sagittal slices using "imageSlicing.cxx'' example](https://discourse.vtk.org/t/visualize-axial-coronal-and-sagittal-slices-using-imageslicing-cxx-example/534)

<div class="topic-metadata">

**Author:** [@Marco\_Festugato](https://discourse.vtk.org/u/Marco_Festugato)\
**Replies:** 0\
**Last updated:** [March 19, 2019, 5:08pm UTC](https://discourse.vtk.org/t/visualize-axial-coronal-and-sagittal-slices-using-imageslicing-cxx-example/534 "2019-03-19T17:08:19Z")

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Hi guys, I’m very new to VTK. What i want to do is use the ‘imageSlicing’ example and adapt it at my needs: I have to do what the example does (cut a 3D volume in slices), but also i have to show the 3 different slices …

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## [Who opened the window for vtk python examples?](https://discourse.vtk.org/t/who-opened-the-window-for-vtk-python-examples/529)

<div class="topic-metadata">

**Author:** [@tdchen](https://discourse.vtk.org/u/tdchen)\
**Replies:** 0\
**Last updated:** [March 19, 2019, 8:53am UTC](https://discourse.vtk.org/t/who-opened-the-window-for-vtk-python-examples/529 "2019-03-19T08:53:14Z")

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As I understand python has no function for drawing and window. So I want to know who is opening the window for vtk python examples? Is it TK or QT? For sometimes, you can’t run vtk python examples, untill you set QT d…

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## [VTK produces aliased images when off-screen rendering is on. How do we get rid of it ?](https://discourse.vtk.org/t/vtk-produces-aliased-images-when-off-screen-rendering-is-on-how-do-we-get-rid-of-it/398)

<div class="topic-metadata">

**Author:** [@singularity](https://discourse.vtk.org/u/singularity)\
**Replies:** 7\
**Last updated:** [March 18, 2019, 4:57pm UTC](https://discourse.vtk.org/t/vtk-produces-aliased-images-when-off-screen-rendering-is-on-how-do-we-get-rid-of-it/398 "2019-03-18T16:57:15Z")

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Hi. I do not understand why VTK produces aliased images when rendering off screen. I have the following code #include \<vtkCamera.h\> #include \<vtkConeSource.h\> #include \<vtkNamedColors.h\> #include \<vtkNew.h\> #include \<vt…

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## [Filter vertices using a implicit function](https://discourse.vtk.org/t/filter-vertices-using-a-implicit-function/503)

<div class="topic-metadata">

**Author:** [@lmainguy](https://discourse.vtk.org/u/lmainguy)\
**Replies:** 6\
**Last updated:** [March 18, 2019, 3:33pm UTC](https://discourse.vtk.org/t/filter-vertices-using-a-implicit-function/503 "2019-03-18T15:33:09Z")

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Hi, I’d like to select the vertices of a polydata, and their associated triangles, based on a condition using an implicit function. So it would be something like select my vertice if its position satisfies an inequality…

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## [CannyEdge PolyData to ImageData](https://discourse.vtk.org/t/cannyedge-polydata-to-imagedata/509)

<div class="topic-metadata">

**Author:** [@pettaa123](https://discourse.vtk.org/u/pettaa123)\
**Replies:** 0\
**Last updated:** [March 17, 2019, 6:47pm UTC](https://discourse.vtk.org/t/cannyedge-polydata-to-imagedata/509 "2019-03-17T18:47:08Z")

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Hi, is there a elegant way from the CannyEdgeDetector example vtkPolyData to vtkImageData? I would like to add the edge result to a vtkImageActor, to forces the camera to stay perpendicular to the x-y plane. The vtkPo…

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## [.vtr Import & Isosurfaces](https://discourse.vtk.org/t/vtr-import-isosurfaces/506)

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**Author:** [@S97](https://discourse.vtk.org/u/S97)\
**Replies:** 3\
**Last updated:** [March 17, 2019, 3:48pm UTC](https://discourse.vtk.org/t/vtr-import-isosurfaces/506 "2019-03-17T15:48:56Z")

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Hello all, I was wondering if I could get some help/clarification on a few things. I have a 30x30x30 rectilinear grid vtk file, this has been pre generated using the pyevtk python extension(GridToVtk). I have successfu…

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## [import 3D volume from ITK to VTK](https://discourse.vtk.org/t/import-3d-volume-from-itk-to-vtk/497)

<div class="topic-metadata">

**Author:** [@Marco\_Festugato](https://discourse.vtk.org/u/Marco_Festugato)\
**Replies:** 12\
**Last updated:** [March 17, 2019, 8:13am UTC](https://discourse.vtk.org/t/import-3d-volume-from-itk-to-vtk/497 "2019-03-17T08:13:12Z")

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Hi guys! I’ve managed to read 200 DICOM files and use them to compose a volume…how can i pass this volume to VTK in order to actually see it? Thank u all for your answer :slight\_smile:

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## [Scroll through 2d slices of 3d volume - ultrasound .mhd file](https://discourse.vtk.org/t/scroll-through-2d-slices-of-3d-volume-ultrasound-mhd-file/102)

<div class="topic-metadata">

**Author:** [@swetha](https://discourse.vtk.org/u/swetha)\
**Replies:** 3\
**Last updated:** [March 15, 2019, 6:37pm UTC](https://discourse.vtk.org/t/scroll-through-2d-slices-of-3d-volume-ultrasound-mhd-file/102 "2019-03-15T18:37:08Z")

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Hi , I am new to vtk ,I want to display a 3d volume of .mhd file. I reused the following code which I got off the net ,made some changes to support vtk6.\` /\*==============================================================…

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## [demystifiying color discretization](https://discourse.vtk.org/t/demystifiying-color-discretization/117)

<div class="topic-metadata">

**Author:** [@embeddedmz](https://discourse.vtk.org/u/embeddedmz)\
**Replies:** 11\
**Last updated:** [March 14, 2019, 2:57pm UTC](https://discourse.vtk.org/t/demystifiying-color-discretization/117 "2019-03-14T14:57:18Z")

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Hi, In the past, I had a slow rendering problem. At the time, the problem was color management with ‘vtkColorTransferFunction’. I solved the problem by using a ‘vtkLookupTable’ along with the ‘vtkColorTransferFunction’…

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## [vtkSplineWidget(2) vtkMarchingSquares and vtkImageData](https://discourse.vtk.org/t/vtksplinewidget-2-vtkmarchingsquares-and-vtkimagedata/464)

<div class="topic-metadata">

**Author:** [@Romain](https://discourse.vtk.org/u/Romain)\
**Replies:** 1\
**Last updated:** [March 14, 2019, 8:22am UTC](https://discourse.vtk.org/t/vtksplinewidget-2-vtkmarchingsquares-and-vtkimagedata/464 "2019-03-14T08:22:58Z")

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Hello everyone, I’m working with vtk 8.2 on Windows 10 with VS 2017. I try to create a closed Spline around the contour of a binary image in purpose to change the value of each pixels inside the closed spline. To do t…

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## [Convert VTI File to Numpy Array in Python Programming](https://discourse.vtk.org/t/convert-vti-file-to-numpy-array-in-python-programming/459)

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**Author:** [@qmaaj](https://discourse.vtk.org/u/qmaaj)\
**Replies:** 2\
**Last updated:** [March 13, 2019, 7:50pm UTC](https://discourse.vtk.org/t/convert-vti-file-to-numpy-array-in-python-programming/459 "2019-03-13T19:50:03Z")

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Suppose I have a vti file containing a scalar field (such as velocity) and its corresponding spatial coordinates (x, y, z coordinates), how should I read the vti file using Python programming and convert the vtil file to…

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## [Update of WIKI on building VTK in visual studio](https://discourse.vtk.org/t/update-of-wiki-on-building-vtk-in-visual-studio/429)

<div class="topic-metadata">

**Author:** [@rdbrn](https://discourse.vtk.org/u/rdbrn)\
**Replies:** 5\
**Last updated:** [March 13, 2019, 2:11pm UTC](https://discourse.vtk.org/t/update-of-wiki-on-building-vtk-in-visual-studio/429 "2019-03-13T14:11:47Z")

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Hi there, I just went through the wiki (https://vtk.org/Wiki/VTK/Building/Windows) on building VTK on windows using visual studio. I had quite some trouble getting it all to work. Especially as the last step (install) r…

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## ["How to render the pixel contour of an image" Follow-Up](https://discourse.vtk.org/t/how-to-render-the-pixel-contour-of-an-image-follow-up/463)

<div class="topic-metadata">

**Author:** [@Harry](https://discourse.vtk.org/u/Harry)\
**Replies:** 3\
**Last updated:** [March 13, 2019, 12:02am UTC](https://discourse.vtk.org/t/how-to-render-the-pixel-contour-of-an-image-follow-up/463 "2019-03-13T00:02:54Z")

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I have a follow-up question to this thread: https://public.kitware.com/pipermail/vtkusers/2011-June/068268.html I have the same problem that his example pictures demonstrate well - I want to render the edges of the “ins…

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## [How to create ResliceAxes from two points in vtkImageReslice](https://discourse.vtk.org/t/how-to-create-resliceaxes-from-two-points-in-vtkimagereslice/466)

<div class="topic-metadata">

**Author:** [@richardander](https://discourse.vtk.org/u/richardander)\
**Replies:** 0\
**Last updated:** [March 12, 2019, 7:26pm UTC](https://discourse.vtk.org/t/how-to-create-resliceaxes-from-two-points-in-vtkimagereslice/466 "2019-03-12T19:26:07Z")

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I would like to use vtkImageReslice to get the cross section of a curve at a point P0. To compute the reslixeAxes, I would like to use P0 and its neighboring point P1 to decisde the direction. As you know, resliceAxes …

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## [world coordinates do not give the correct dicom coordinate](https://discourse.vtk.org/t/world-coordinates-do-not-give-the-correct-dicom-coordinate/452)

<div class="topic-metadata">

**Author:** [@zandarina](https://discourse.vtk.org/u/zandarina)\
**Replies:** 0\
**Last updated:** [March 11, 2019, 5:25pm UTC](https://discourse.vtk.org/t/world-coordinates-do-not-give-the-correct-dicom-coordinate/452 "2019-03-11T17:25:11Z")

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Dear all, I want to do segmentation with itk and i would like to select a seed using vtk with the mouse. I get the coordinates in world coordinates int x = this-\>Interactor-\>GetEventPosition()\[0\]; …

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