# Support

**URL:** https://discourse.vtk.org/c/support/6.md?page=107

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

**Page:** 108

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## [vtkDataWriter crashes with an array that is a vtkMappedDataArray subclass](https://discourse.vtk.org/t/vtkdatawriter-crashes-with-an-array-that-is-a-vtkmappeddataarray-subclass/5517)

<div class="topic-metadata">

**Author:** [@biagas](https://discourse.vtk.org/u/biagas)\
**Replies:** 2\
**Last updated:** [April 8, 2021, 3:00pm UTC](https://discourse.vtk.org/t/vtkdatawriter-crashes-with-an-array-that-is-a-vtkmappeddataarray-subclass/5517 "2021-04-08T15:00:17Z")

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I am using VTK-8.1.0 and attempting to create subclass of vtkMappedDataArray for use with non-AOS data. I used vtkCPExodusIINodalCoordinatesTemplate as a guide. My subclass is being used to represent vtkStructuredGrid c…

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## [Compiling VTK Python with OSPRay](https://discourse.vtk.org/t/compiling-vtk-python-with-ospray/5491)

<div class="topic-metadata">

**Author:** [@nantille](https://discourse.vtk.org/u/nantille)\
**Replies:** 10\
**Last updated:** [April 8, 2021, 9:33am UTC](https://discourse.vtk.org/t/compiling-vtk-python-with-ospray/5491 "2021-04-08T09:33:12Z")

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Hello, It’s quite a mystery how to build VTK python with OSPRay. I couldn’t find proper information for building it (in my case on Ubuntu LTS 20). I first tried to clone VTK release branch and compile it with OSPRay. T…

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## [VTKData and VTKLargeData](https://discourse.vtk.org/t/vtkdata-and-vtklargedata/5514)

<div class="topic-metadata">

**Author:** [@thegbiv](https://discourse.vtk.org/u/thegbiv)\
**Replies:** 1\
**Last updated:** [April 7, 2021, 3:46pm UTC](https://discourse.vtk.org/t/vtkdata-and-vtklargedata/5514 "2021-04-07T15:46:06Z")

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Hi all, There was a time where I could checkout/download VTKData and VTKLargeData to have some sample datasets to play around with. I’ve downloaded the links from the download page but I’m not quite clear on how to get …

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## [vtkThreshold not working with vtkMultiBlockDataSet?](https://discourse.vtk.org/t/vtkthreshold-not-working-with-vtkmultiblockdataset/5406)

<div class="topic-metadata">

**Author:** [@scotsman60](https://discourse.vtk.org/u/scotsman60)\
**Replies:** 3\
**Last updated:** [April 7, 2021, 3:18pm UTC](https://discourse.vtk.org/t/vtkthreshold-not-working-with-vtkmultiblockdataset/5406 "2021-04-07T15:18:16Z")

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I’m trying to threshold datasets in a vtkMultiBlockDataSet, but the filter returns a None type - I’m working in Python 3.8.2 and vtk 9.0.1 The code fragment is shown below and export is returned as None The input is a …

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## [boolean library for meshes with vtk bridget](https://discourse.vtk.org/t/boolean-library-for-meshes-with-vtk-bridget/5510)

<div class="topic-metadata">

**Author:** [@zandarina](https://discourse.vtk.org/u/zandarina)\
**Replies:** 0\
**Last updated:** [April 7, 2021, 8:15am UTC](https://discourse.vtk.org/t/boolean-library-for-meshes-with-vtk-bridget/5510 "2021-04-07T08:15:59Z")

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Hello, I wonder if you can recommend me a powerful boolean library for meshes that can be easily adapted to vtk. I have tried vtkbool library. The result is ok but when I want to get the larger connected component, I on…

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## [Why vtkMetaImageReader read a .mha file, the memory blast?](https://discourse.vtk.org/t/why-vtkmetaimagereader-read-a-mha-file-the-memory-blast/5506)

<div class="topic-metadata">

**Author:** [@wulicheng](https://discourse.vtk.org/u/wulicheng)\
**Replies:** 0\
**Last updated:** [April 7, 2021, 12:52am UTC](https://discourse.vtk.org/t/why-vtkmetaimagereader-read-a-mha-file-the-memory-blast/5506 "2021-04-07T00:52:45Z")

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vtkSmartPointer imagereader = vtkSmartPointer::New(); imagereader-\>SetFileName(filename); imagereader-\>Update(); this is the code when i read a .mha file just 2.3M, the program memory expand to 1 G? this “filename” j…

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## [Error building SliceCAT](https://discourse.vtk.org/t/error-building-slicecat/5327)

<div class="topic-metadata">

**Author:** [@Jothybasu\_Selvaraj](https://discourse.vtk.org/u/Jothybasu_Selvaraj)\
**Replies:** 3\
**Last updated:** [April 6, 2021, 6:09pm UTC](https://discourse.vtk.org/t/error-building-slicecat/5327 "2021-04-06T18:09:05Z")

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I am trying to customize my application using Slicer but I am getting these errors. Can anyone help me please? Severity Code Description Project Path File Line Suppression State Error LNK2019 unresolved external…

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## [parsing vtu to obj with triangle strips](https://discourse.vtk.org/t/parsing-vtu-to-obj-with-triangle-strips/5501)

<div class="topic-metadata">

**Author:** [@humbletang](https://discourse.vtk.org/u/humbletang)\
**Replies:** 2\
**Last updated:** [April 6, 2021, 1:43am UTC](https://discourse.vtk.org/t/parsing-vtu-to-obj-with-triangle-strips/5501 "2021-04-06T01:43:43Z")

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Hello there, I’m writing a python converter for some simulation files that come out as unstructured grid .vtu but I keep ending up with extra geometry. Could some one tell me from the following data what the final 2 tr…

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## [Interact with stl model by axes separately](https://discourse.vtk.org/t/interact-with-stl-model-by-axes-separately/5414)

<div class="topic-metadata">

**Author:** [@l1va](https://discourse.vtk.org/u/l1va)\
**Replies:** 3\
**Last updated:** [April 5, 2021, 8:13pm UTC](https://discourse.vtk.org/t/interact-with-stl-model-by-axes-separately/5414 "2021-04-05T20:13:59Z")

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Dear All, I want to interact (rotate, move) model by axes separately. Only by X for example. And to do it user-friendly for sure. I found BoxWidget - it is great for scaling, but I didn’t find how to extend it for my n…

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## [vtk.js server site openGL.](https://discourse.vtk.org/t/vtk-js-server-site-opengl/5495)

<div class="topic-metadata">

**Author:** [@Luis\_Carlos\_Carneiro](https://discourse.vtk.org/u/Luis_Carlos_Carneiro)\
**Replies:** 7\
**Last updated:** [April 5, 2021, 6:03pm UTC](https://discourse.vtk.org/t/vtk-js-server-site-opengl/5495 "2021-04-05T18:03:32Z")

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Dear All, In web-project-templates-master example it is created an OpenGL window in the server side. For that it is needed a Graphics card that supports OpenGL. Can that window be created/mapped in RAM memory and withou…

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## [How to access Point coordinates as PointData arrays?](https://discourse.vtk.org/t/how-to-access-point-coordinates-as-pointdata-arrays/5484)

<div class="topic-metadata">

**Author:** [@scotsman60](https://discourse.vtk.org/u/scotsman60)\
**Replies:** 2\
**Last updated:** [April 2, 2021, 10:00pm UTC](https://discourse.vtk.org/t/how-to-access-point-coordinates-as-pointdata-arrays/5484 "2021-04-02T22:00:13Z")

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Hello!!! I want to use the coordinates of Points in an unstucturedGrid as part of an equation in vtkArrayCalculator. In Paraview, I cann access the point coordinates as vector PointData using the array name ‘coords’ -…

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## [Best Way to Convert Structured Points Vtk File into DICOM?](https://discourse.vtk.org/t/best-way-to-convert-structured-points-vtk-file-into-dicom/5483)

<div class="topic-metadata">

**Author:** [@searica](https://discourse.vtk.org/u/searica)\
**Replies:** 1\
**Last updated:** [April 2, 2021, 3:24pm UTC](https://discourse.vtk.org/t/best-way-to-convert-structured-points-vtk-file-into-dicom/5483 "2021-04-02T15:24:32Z")

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I’ve got a structured points file I made with Houndsfield values for each point and I would like to convert into into a DICOM file that can be read imported into Mimics or 3D Slicer. I found this http://gdcm.sourceforge.…

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## [Controlling text property for vtkLabelPlacementMapper](https://discourse.vtk.org/t/controlling-text-property-for-vtklabelplacementmapper/5487)

<div class="topic-metadata">

**Author:** [@subhacom](https://discourse.vtk.org/u/subhacom)\
**Replies:** 1\
**Last updated:** [April 2, 2021, 12:46pm UTC](https://discourse.vtk.org/t/controlling-text-property-for-vtklabelplacementmapper/5487 "2021-04-02T12:46:24Z")

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I am displaying some labels on a set of points in Python using vtkLabelPlacementMapper. The problem is the text is rendered in white by default, and becomes invisible when the background color is white as well. Looking…

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## [Custom Shader vs Camera Frustrum for infinite plane](https://discourse.vtk.org/t/custom-shader-vs-camera-frustrum-for-infinite-plane/5481)

<div class="topic-metadata">

**Author:** [@j-miguel](https://discourse.vtk.org/u/j-miguel)\
**Replies:** 0\
**Last updated:** [April 1, 2021, 10:24pm UTC](https://discourse.vtk.org/t/custom-shader-vs-camera-frustrum-for-infinite-plane/5481 "2021-04-01T22:24:38Z")

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Dear All, I’m currently using VTK (7.1.1) to create off-shore simulations. I got the sea bottom working using Delaunay from bathymetric point cloud. Now, I’m trying to create a visual representation of the sea as an a…

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## [Inconsistent Render of Colored PolyData](https://discourse.vtk.org/t/inconsistent-render-of-colored-polydata/5396)

<div class="topic-metadata">

**Author:** [@ksh\_co](https://discourse.vtk.org/u/ksh_co)\
**Replies:** 1\
**Last updated:** [April 1, 2021, 7:25pm UTC](https://discourse.vtk.org/t/inconsistent-render-of-colored-polydata/5396 "2021-04-01T19:25:23Z")

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Hi, I have a number of unstructured meshes (of right ventricles) converted to PolyData on which I am attempting to identify physiologically relevant regions (septal wall, free wall, valves, etc). Based on location, curv…

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## [VTK Lights](https://discourse.vtk.org/t/vtk-lights/5479)

<div class="topic-metadata">

**Author:** [@Frank\_Gao](https://discourse.vtk.org/u/Frank_Gao)\
**Replies:** 0\
**Last updated:** [April 1, 2021, 1:13am UTC](https://discourse.vtk.org/t/vtk-lights/5479 "2021-04-01T01:13:50Z")

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Dear VTK experts, I am wondering how many lights we can add to a renderer. I am add bunch of lights, but quickly VTK 9 crashed with message that stack was corrupted in light color code, or somewhere else in vtkLight con…

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## [Java build questions](https://discourse.vtk.org/t/java-build-questions/5462)

<div class="topic-metadata">

**Author:** [@Gilthalas](https://discourse.vtk.org/u/Gilthalas)\
**Replies:** 9\
**Last updated:** [March 31, 2021, 10:14pm UTC](https://discourse.vtk.org/t/java-build-questions/5462 "2021-03-31T22:14:10Z")

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Hi all - happy to say we are having great success building and using VTK 9 in our upgraded tool. We did have a few questions related to the overall Java build process though. First, when the jnilibs are built, they e…

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## [vtk render unstructured grid and set active camera](https://discourse.vtk.org/t/vtk-render-unstructured-grid-and-set-active-camera/336)

<div class="topic-metadata">

**Author:** [@francisco\_munoz](https://discourse.vtk.org/u/francisco_munoz)\
**Replies:** 3\
**Last updated:** [March 31, 2021, 11:56am UTC](https://discourse.vtk.org/t/vtk-render-unstructured-grid-and-set-active-camera/336 "2021-03-31T11:56:04Z")

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hi all, i’m trying to do a render of a unstructured grid by setting the camera before interactor. When i render just the unstructured grid alll works fine but when i try to set a custom camera at a given possition it gi…

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## [Qt widgets over the QVTKWidget in Python: no transparency](https://discourse.vtk.org/t/qt-widgets-over-the-qvtkwidget-in-python-no-transparency/5465)

<div class="topic-metadata">

**Author:** [@jean](https://discourse.vtk.org/u/jean)\
**Replies:** 3\
**Last updated:** [March 30, 2021, 7:20pm UTC](https://discourse.vtk.org/t/qt-widgets-over-the-qvtkwidget-in-python-no-transparency/5465 "2021-03-30T19:20:21Z")

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Hi, I can put Qt widgets over the VTK widget in Python, but a few stange things happen when I do. Transparency doesn’t work. The color changes slowly when moving the mouse cursor over the button and reset only when re…

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## [Paraview is not saving stl file with SaveData](https://discourse.vtk.org/t/paraview-is-not-saving-stl-file-with-savedata/5445)

<div class="topic-metadata">

**Author:** [@rasunag27](https://discourse.vtk.org/u/rasunag27)\
**Replies:** 4\
**Last updated:** [March 30, 2021, 7:19am UTC](https://discourse.vtk.org/t/paraview-is-not-saving-stl-file-with-savedata/5445 "2021-03-30T07:19:37Z")

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Dear All, I used one stl file to split the stl using Paraview. I traced the method using python trace in paraview. Now, I used the code in python to run it. It runs perfectly, but it does not save the splitted mesh as …

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## [visualization of fitted thin plate spline from vtkThinPlateSplineTransform](https://discourse.vtk.org/t/visualization-of-fitted-thin-plate-spline-from-vtkthinplatesplinetransform/5460)

<div class="topic-metadata">

**Author:** [@Bjorn\_Hansen](https://discourse.vtk.org/u/Bjorn_Hansen)\
**Replies:** 2\
**Last updated:** [March 29, 2021, 2:52pm UTC](https://discourse.vtk.org/t/visualization-of-fitted-thin-plate-spline-from-vtkthinplatesplinetransform/5460 "2021-03-29T14:52:22Z")

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Hello, I’m currently using the vtkThinPlateSplineTransform to do data augmentation on a mesh of a heart in Python. I would like to visualize the Thin Plate Spline i have fitted to a set of source and target points such t…

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## [Custom scale of a volume](https://discourse.vtk.org/t/custom-scale-of-a-volume/5458)

<div class="topic-metadata">

**Author:** [@Luis\_Carlos\_Carneiro](https://discourse.vtk.org/u/Luis_Carlos_Carneiro)\
**Replies:** 1\
**Last updated:** [March 29, 2021, 12:22pm UTC](https://discourse.vtk.org/t/custom-scale-of-a-volume/5458 "2021-03-29T12:22:47Z")

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Dear All, Are there some function in VTK that does a dynamic scale of a volume (structured image)? The volume must be scaled not equally but obeying to a scale function that may have first, second derivatives. Or doing…

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## [it takes long time for the iso-surface extraction at first step](https://discourse.vtk.org/t/it-takes-long-time-for-the-iso-surface-extraction-at-first-step/5456)

<div class="topic-metadata">

**Author:** [@1116](https://discourse.vtk.org/u/1116)\
**Replies:** 7\
**Last updated:** [March 29, 2021, 12:12pm UTC](https://discourse.vtk.org/t/it-takes-long-time-for-the-iso-surface-extraction-at-first-step/5456 "2021-03-29T12:12:54Z")

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For my project, the tightly coupled in-situ analytics process the data generated by the simulation at each iteration. The analytics code is just the iso surface extraction based on VTK. I found that the first step of the…

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## [Particle Tracking](https://discourse.vtk.org/t/particle-tracking/4466)

<div class="topic-metadata">

**Author:** [@jbensabat](https://discourse.vtk.org/u/jbensabat)\
**Replies:** 2\
**Last updated:** [March 29, 2021, 11:10am UTC](https://discourse.vtk.org/t/particle-tracking/4466 "2021-03-29T11:10:16Z")

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Hello We are trying to visualize pathlines using particle tracking (vtkParticleTracer) with an unstructured grid there is one example TestParticleTracers, which works on a regular grid. We used the sample example adap…

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## [How to change the property of the vtkBoxWidget2?](https://discourse.vtk.org/t/how-to-change-the-property-of-the-vtkboxwidget2/5457)

<div class="topic-metadata">

**Author:** [@Kim\_William](https://discourse.vtk.org/u/Kim_William)\
**Replies:** 0\
**Last updated:** [March 29, 2021, 8:39am UTC](https://discourse.vtk.org/t/how-to-change-the-property-of-the-vtkboxwidget2/5457 "2021-03-29T08:39:47Z")

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Hi all. I have a question about the vtkBoxWidget2. I’m trying to change the color and thickness of the line of the vtkBoxWidget2. Is it possible to change the property of the vtkBoxWidget2? Could you please give me…

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## [Python VTK example link broken](https://discourse.vtk.org/t/python-vtk-example-link-broken/5453)

<div class="topic-metadata">

**Author:** [@Sh4zKh4n](https://discourse.vtk.org/u/Sh4zKh4n)\
**Replies:** 1\
**Last updated:** [March 29, 2021, 8:05am UTC](https://discourse.vtk.org/t/python-vtk-example-link-broken/5453 "2021-03-29T08:05:31Z")

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Ive been trying to find where the python examples folder is to no avail. The link in the docs goes to no where and if I have a poke through the github it’s missing. Any advice for me where I could find some examples of…

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## [Emissive actor light up other actor with PBR?](https://discourse.vtk.org/t/emissive-actor-light-up-other-actor-with-pbr/5415)

<div class="topic-metadata">

**Author:** [@estan](https://discourse.vtk.org/u/estan)\
**Replies:** 4\
**Last updated:** [March 27, 2021, 10:18am UTC](https://discourse.vtk.org/t/emissive-actor-light-up-other-actor-with-pbr/5415 "2021-03-27T10:18:39Z")

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Hello, Consider this example: import vtk cubeSource = vtk.vtkCubeSource() cubeMapper = vtk.vtkPolyDataMapper() cubeMapper.SetInputConnection(cubeSource.GetOutputPort()) emissiveSource = vtk.vtkImageCanvasSource2D() …

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## [Select closed volume](https://discourse.vtk.org/t/select-closed-volume/5394)

<div class="topic-metadata">

**Author:** [@Luis\_Carlos\_Carneiro](https://discourse.vtk.org/u/Luis_Carlos_Carneiro)\
**Replies:** 5\
**Last updated:** [March 26, 2021, 5:51pm UTC](https://discourse.vtk.org/t/select-closed-volume/5394 "2021-03-26T17:51:15Z")

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Dear All, If I have a single volume (in VTK terms) formed by several closed “volumes”. How I select the points of one of those “volumes” and for example change the color of it? Perhaps, selecting one of the points of t…

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## [vtkDistancePolyDataFilter not working with contours?](https://discourse.vtk.org/t/vtkdistancepolydatafilter-not-working-with-contours/5437)

<div class="topic-metadata">

**Author:** [@Ingmar](https://discourse.vtk.org/u/Ingmar)\
**Replies:** 1\
**Last updated:** [March 25, 2021, 1:40pm UTC](https://discourse.vtk.org/t/vtkdistancepolydatafilter-not-working-with-contours/5437 "2021-03-25T13:40:17Z")

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Dear VTK experts, I am trying to use a vtkDistancePolyDataFilter out of python (using vtk==8.1.2 pkg). This seems to work fine for triangle meshes. reader1 = vtk.vtkPolyDataReader() reader1.SetFileName('E:/temp/mes…

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## [Fitting stl file on 2D image](https://discourse.vtk.org/t/fitting-stl-file-on-2d-image/5430)

<div class="topic-metadata">

**Author:** [@Amir\_Hossein\_Zeydi](https://discourse.vtk.org/u/Amir_Hossein_Zeydi)\
**Replies:** 0\
**Last updated:** [March 23, 2021, 7:08pm UTC](https://discourse.vtk.org/t/fitting-stl-file-on-2d-image/5430 "2021-03-23T19:08:37Z")

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I used the code below and I wanted to match a 3D stl on an image: both files are same size but when you open them in two renderer layers they dont match, I tried using pixel sizing to scale but it didnt work either. …

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