# Latest

**URL:** https://discourse.vtk.org/latest.md?page=189

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

**Page:** 190

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## [VTK provide three different world point converted from three methods with one display point](https://discourse.vtk.org/t/vtk-provide-three-different-world-point-converted-from-three-methods-with-one-display-point/4843)

<div class="topic-metadata">

**Author:** [@zhang-qiang-github](https://discourse.vtk.org/u/zhang-qiang-github)\
**Replies:** 4\
**Last updated:** [December 24, 2020, 1:46pm UTC](https://discourse.vtk.org/t/vtk-provide-three-different-world-point-converted-from-three-methods-with-one-display-point/4843 "2020-12-24T13:46:39Z")

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I am using VTK in my project, and I need to get the world point from a display point. I find three method: vtkPropPicker, vtkCellPicker, vtkCoordinate. But I find they return different world point for the same display p…

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## [VTK: vtkSurfaceReconstructionFilter Inaccurate rendering results in 3D](https://discourse.vtk.org/t/vtk-vtksurfacereconstructionfilter-inaccurate-rendering-results-in-3d/4884)

<div class="topic-metadata">

**Author:** [@Pandapan](https://discourse.vtk.org/u/Pandapan)\
**Replies:** 1\
**Last updated:** [December 24, 2020, 12:47pm UTC](https://discourse.vtk.org/t/vtk-vtksurfacereconstructionfilter-inaccurate-rendering-results-in-3d/4884 "2020-12-24T12:47:39Z")

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There are many points in 3D, we use them for volume rendering by vtkSurfaceReconstructionFilter，But the results seem ugly, and I wonder what the problem is? Here are my code and results： auto colors = vtkSmartPointer\<…

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## [question about the type transfer from vtkDataObject to vtkPolyData](https://discourse.vtk.org/t/question-about-the-type-transfer-from-vtkdataobject-to-vtkpolydata/4888)

<div class="topic-metadata">

**Author:** [@1116](https://discourse.vtk.org/u/1116)\
**Replies:** 0\
**Last updated:** [December 24, 2020, 6:00am UTC](https://discourse.vtk.org/t/question-about-the-type-transfer-from-vtkdataobject-to-vtkpolydata/4888 "2020-12-24T06:00:47Z")

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Hello, I try to gather the polydata generated by different processes into one processes based on vtkMPIController, and then aggregate them into one data set for further processing by following code: ...... std:…

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## [Configuring with external dependencies](https://discourse.vtk.org/t/configuring-with-external-dependencies/4887)

<div class="topic-metadata">

**Author:** [@aisha](https://discourse.vtk.org/u/aisha)\
**Replies:** 1\
**Last updated:** [December 24, 2020, 4:56am UTC](https://discourse.vtk.org/t/configuring-with-external-dependencies/4887 "2020-12-24T04:56:24Z")

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I’m trying to upgrade the Gentoo Linux VTK package and am currently unable to see how to make VTK use external libraries instead of internal ones, like say for loguru and utf8cpp. Could anyone point out what options I n…

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## [Gets the dimensions of an explicit structured grid](https://discourse.vtk.org/t/gets-the-dimensions-of-an-explicit-structured-grid/4871)

<div class="topic-metadata">

**Author:** [@rodrigomologni](https://discourse.vtk.org/u/rodrigomologni)\
**Replies:** 3\
**Last updated:** [December 23, 2020, 11:53am UTC](https://discourse.vtk.org/t/gets-the-dimensions-of-an-explicit-structured-grid/4871 "2020-12-23T11:53:16Z")

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Support, How can I get the dimensions of an explicit structured grid by means of Python code, please? print(grid.GetDimensions()) TypeError: GetDimensions() takes exactly 1 argument (0 given) GetDimensions returns not…

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## [What version of OpenGL does VTK use?](https://discourse.vtk.org/t/what-version-of-opengl-does-vtk-use/4868)

<div class="topic-metadata">

**Author:** [@Brady\_Hales](https://discourse.vtk.org/u/Brady_Hales)\
**Replies:** 1\
**Last updated:** [December 23, 2020, 10:16am UTC](https://discourse.vtk.org/t/what-version-of-opengl-does-vtk-use/4868 "2020-12-23T10:16:17Z")

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I am using the latest version of VTK but I think I am having trouble with some of the OpenGL libraries with my graphics card. Does anybody know what version of OpenGL is used with the latest VTK libraries? Thanks,

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## [VTK: how to set the threshold for vtkPropPicker](https://discourse.vtk.org/t/vtk-how-to-set-the-threshold-for-vtkproppicker/4833)

<div class="topic-metadata">

**Author:** [@zhang-qiang-github](https://discourse.vtk.org/u/zhang-qiang-github)\
**Replies:** 3\
**Last updated:** [December 23, 2020, 2:38am UTC](https://discourse.vtk.org/t/vtk-how-to-set-the-threshold-for-vtkproppicker/4833 "2020-12-23T02:38:17Z")

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When click the mouse, vtkPropPicker can decide whether a actor is selected. I wonder whether can we set a threshold to decide whether the actor is selected? For example, if the distance between the mouse click position …

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## [vtkImageActor interpolation limited to linear](https://discourse.vtk.org/t/vtkimageactor-interpolation-limited-to-linear/4858)

<div class="topic-metadata">

**Author:** [@spencermanwell](https://discourse.vtk.org/u/spencermanwell)\
**Replies:** 7\
**Last updated:** [December 22, 2020, 10:02pm UTC](https://discourse.vtk.org/t/vtkimageactor-interpolation-limited-to-linear/4858 "2020-12-22T22:02:00Z")

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Hi there, I use VTK to display medical images like CT and MR, which in the medical imaging domain are high-resolution imaging modalities. My problem is that when I render these images linear artifacts along pixel bounda…

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## [Volume rendering 'clipping?' with ImageData.setSpacing(\[1, 1, 10\]) and zoom/dolly-in](https://discourse.vtk.org/t/volume-rendering-clipping-with-imagedata-setspacing-1-1-10-and-zoom-dolly-in/4828)

<div class="topic-metadata">

**Author:** [@PaulHax](https://discourse.vtk.org/u/PaulHax)\
**Replies:** 1\
**Last updated:** [December 22, 2020, 12:06am UTC](https://discourse.vtk.org/t/volume-rendering-clipping-with-imagedata-setspacing-1-1-10-and-zoom-dolly-in/4828 "2020-12-22T00:06:08Z")

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Hello VTK Folks, I’ve got 512 by 512 images of around ~200 frames I’ve put into a vtkImageData. The frame are spaced apart in physical space so I’d like to scale the rendered volume along the Z axis. Use imageData.set…

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## [How to add the color of gray image to point cloud](https://discourse.vtk.org/t/how-to-add-the-color-of-gray-image-to-point-cloud/4856)

<div class="topic-metadata">

**Author:** [@Ethan](https://discourse.vtk.org/u/Ethan)\
**Replies:** 3\
**Last updated:** [December 21, 2020, 7:16pm UTC](https://discourse.vtk.org/t/how-to-add-the-color-of-gray-image-to-point-cloud/4856 "2020-12-21T19:16:02Z")

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When I use the settablevalue function in vtklookuptable, I can only set the value of RGBA, but my image is a gray image. How can I set the color to the point cloud?

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## [coincident topology offset parameters](https://discourse.vtk.org/t/coincident-topology-offset-parameters/4836)

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**Author:** [@andreasbuykx](https://discourse.vtk.org/u/andreasbuykx)\
**Replies:** 2\
**Last updated:** [December 21, 2020, 5:17pm UTC](https://discourse.vtk.org/t/coincident-topology-offset-parameters/4836 "2020-12-21T17:17:25Z")

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I am working on migrating our FEA application from VTK 8.1.1 to VTK 9.0.1. As a result of the changes to how coincident topology resolution is implemented I get a lot of changes. sometimes they are improvements but un…

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## [Python example for GLTF export/import](https://discourse.vtk.org/t/python-example-for-gltf-export-import/4596)

<div class="topic-metadata">

**Author:** [@desheng](https://discourse.vtk.org/u/desheng)\
**Replies:** 4\
**Last updated:** [December 21, 2020, 2:04pm UTC](https://discourse.vtk.org/t/python-example-for-gltf-export-import/4596 "2020-12-21T14:04:55Z")

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Is it possible to provide an example in Python like in CXX https://lorensen.github.io/VTKExamples/site/Cxx/IO/GLTFExporter/ for GLTF export/import? Thanks!

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## [image pixel values and background for 3d rendering](https://discourse.vtk.org/t/image-pixel-values-and-background-for-3d-rendering/4162)

<div class="topic-metadata">

**Author:** [@YolkandWhite](https://discourse.vtk.org/u/YolkandWhite)\
**Replies:** 7\
**Last updated:** [December 21, 2020, 9:53am UTC](https://discourse.vtk.org/t/image-pixel-values-and-background-for-3d-rendering/4162 "2020-12-21T09:53:16Z")

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Hi, I am new to VTK. I have a question about how the pixel value works in 3d rendering. what I’m trying to do is segment the ROI region of stacked 2d image and 3d volume render the ROIs. If the pixel value is 0, does …

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## [vtkAxesActor Fails to Render at Some Angles](https://discourse.vtk.org/t/vtkaxesactor-fails-to-render-at-some-angles/4864)

<div class="topic-metadata">

**Author:** [@nchampag](https://discourse.vtk.org/u/nchampag)\
**Replies:** 2\
**Last updated:** [September 9, 2025, 4:04pm UTC](https://discourse.vtk.org/t/vtkaxesactor-fails-to-render-at-some-angles/4864 "2025-09-09T16:04:57Z")

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After upgrading from 8.2.0 to 9.0.1, VTK AxesActors do not render at certain angles. Here is a Python script that demonstrates this: # This script demonstrates that the vtkAxesActor is not drawn between phi = 91 degr…

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## [Error during the cell blanking of explicit structured grid](https://discourse.vtk.org/t/error-during-the-cell-blanking-of-explicit-structured-grid/4863)

<div class="topic-metadata">

**Author:** [@rodrigomologni](https://discourse.vtk.org/u/rodrigomologni)\
**Replies:** 3\
**Last updated:** [December 20, 2020, 9:00pm UTC](https://discourse.vtk.org/t/error-during-the-cell-blanking-of-explicit-structured-grid/4863 "2020-12-20T21:00:45Z")

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Cell blanking (vtkDataSetAttributes.HIDDENCELL) of explicit structured grids produces the following error: ERROR:root:Invalid cell type: 0 2020-12-19 23:24:55.908 ( 11.046s) \[ \] vtkPolyData.cxx:10…

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## [Python backend send via JSON to vtk.js](https://discourse.vtk.org/t/python-backend-send-via-json-to-vtk-js/4852)

<div class="topic-metadata">

**Author:** [@rich](https://discourse.vtk.org/u/rich)\
**Replies:** 6\
**Last updated:** [December 20, 2020, 8:16pm UTC](https://discourse.vtk.org/t/python-backend-send-via-json-to-vtk-js/4852 "2020-12-20T20:16:26Z")

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Hi, I am running a python web-server which is calculating the new geometry of a model to then send back to the website visualiser using vtk.js to visualise the information. I would like to send the updated geometry usin…

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## [vtkAppendPolyData does not include the scalar information](https://discourse.vtk.org/t/vtkappendpolydata-does-not-include-the-scalar-information/4850)

<div class="topic-metadata">

**Author:** [@zandarina](https://discourse.vtk.org/u/zandarina)\
**Replies:** 2\
**Last updated:** [December 20, 2020, 11:33am UTC](https://discourse.vtk.org/t/vtkappendpolydata-does-not-include-the-scalar-information/4850 "2020-12-20T11:33:21Z")

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Hello, I am tryng to append two polydatas with scalar info so according to the class information if both have scalar information the output should also include it. But i am trying it of many ways and the results does no…

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## [extracting (or creating) vtkSmartPointer from Python-wrapped VTK object](https://discourse.vtk.org/t/extracting-or-creating-vtksmartpointer-from-python-wrapped-vtk-object/2407)

<div class="topic-metadata">

**Author:** [@stefanseefeld](https://discourse.vtk.org/u/stefanseefeld)\
**Replies:** 2\
**Last updated:** [December 20, 2020, 2:03am UTC](https://discourse.vtk.org/t/extracting-or-creating-vtksmartpointer-from-python-wrapped-vtk-object/2407 "2020-12-20T02:03:04Z")

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I’d like to integrate VTK/Python into my own project, which uses a mix of C++ and Python code. I need to call functions that take vtkSmartPointer arguments with object references I have extracted from VTK/Python wrapper…

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## [Image Data to Point Cloud](https://discourse.vtk.org/t/image-data-to-point-cloud/4841)

<div class="topic-metadata">

**Author:** [@sandress](https://discourse.vtk.org/u/sandress)\
**Replies:** 3\
**Last updated:** [December 19, 2020, 5:10pm UTC](https://discourse.vtk.org/t/image-data-to-point-cloud/4841 "2020-12-19T17:10:57Z")

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Hi everyone, I’m searching for a way to create a semi-random point cloud thats density in specific areas is defined by an underlying CT image. E.g. in areas with an high HU-value the point cloud should be dense as in lo…

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## [serialize a vtk object](https://discourse.vtk.org/t/serialize-a-vtk-object/4831)

<div class="topic-metadata">

**Author:** [@SArbabi](https://discourse.vtk.org/u/SArbabi)\
**Replies:** 15\
**Last updated:** [December 18, 2020, 5:29pm UTC](https://discourse.vtk.org/t/serialize-a-vtk-object/4831 "2020-12-18T17:29:08Z")

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How is a good way to serialize objects like vtkPolyData to transmit between client and server? actually I create a point cloud in javascript and want to send it to python script on server to do some processing and send …

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## [Obtaining the curve of intersection in vtk](https://discourse.vtk.org/t/obtaining-the-curve-of-intersection-in-vtk/4769)

<div class="topic-metadata">

**Author:** [@Anish\_Basnet](https://discourse.vtk.org/u/Anish_Basnet)\
**Replies:** 5\
**Last updated:** [December 18, 2020, 10:02am UTC](https://discourse.vtk.org/t/obtaining-the-curve-of-intersection-in-vtk/4769 "2020-12-18T10:02:46Z")

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Hello everyone, Is there a function in VTK that could determine the curve of intersection between two polydatas? I’d also like to obtain the points that lie in the curve(indicated by the red color in the figure below).…

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## [Image Registration and Fusion](https://discourse.vtk.org/t/image-registration-and-fusion/4807)

<div class="topic-metadata">

**Author:** [@dporter](https://discourse.vtk.org/u/dporter)\
**Replies:** 2\
**Last updated:** [December 17, 2020, 9:50pm UTC](https://discourse.vtk.org/t/image-registration-and-fusion/4807 "2020-12-17T21:50:59Z")

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Hello All, I am on the hunt for Image Fusion examples or open source apps that I can use for my work at the Mayo Clinic. Does anyone have software you are will to share? Thanks.

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## [Deform a CT image volume using the vtkImageReslice](https://discourse.vtk.org/t/deform-a-ct-image-volume-using-the-vtkimagereslice/4848)

<div class="topic-metadata">

**Author:** [@isuruwi](https://discourse.vtk.org/u/isuruwi)\
**Replies:** 4\
**Last updated:** [December 17, 2020, 8:03pm UTC](https://discourse.vtk.org/t/deform-a-ct-image-volume-using-the-vtkimagereslice/4848 "2020-12-17T20:03:24Z")

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I want to apply transformations such as translate, scale, rotation to a given 3D CT image volume (mhd format). For that I have used vtkImageReslice function as below. But the output seems not correctly deformed as expect…

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## [Points of inflection of a polydata Curve](https://discourse.vtk.org/t/points-of-inflection-of-a-polydata-curve/4849)

<div class="topic-metadata">

**Author:** [@Anish\_Basnet](https://discourse.vtk.org/u/Anish_Basnet)\
**Replies:** 0\
**Last updated:** [December 17, 2020, 4:25pm UTC](https://discourse.vtk.org/t/points-of-inflection-of-a-polydata-curve/4849 "2020-12-17T16:25:29Z")

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Hello everyone, Is there any way to obtain points of inflection in VTK? I found out that a filter called vtkDecimatePro does offer a possibility. But it works only with triangular meshes. The curve that I have obtained…

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## [OBJViewer: Issue with displaying some zip files in Chrome for Android](https://discourse.vtk.org/t/objviewer-issue-with-displaying-some-zip-files-in-chrome-for-android/4844)

<div class="topic-metadata">

**Author:** [@y-polek](https://discourse.vtk.org/u/y-polek)\
**Replies:** 0\
**Last updated:** [December 17, 2020, 12:07pm UTC](https://discourse.vtk.org/t/objviewer-issue-with-displaying-some-zip-files-in-chrome-for-android/4844 "2020-12-17T12:07:49Z")

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I’m using OBJViewer.html to open zip files. I have an issue with some files: the object is black and the texture isn’t applied. The same zip files work just fine on desktop browsers. Also, in a Chrome console I can se…

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## [Coordinates of point in a 3D Image](https://discourse.vtk.org/t/coordinates-of-point-in-a-3d-image/4837)

<div class="topic-metadata">

**Author:** [@Luis\_Carlos\_Carneiro](https://discourse.vtk.org/u/Luis_Carlos_Carneiro)\
**Replies:** 1\
**Last updated:** [December 16, 2020, 10:37pm UTC](https://discourse.vtk.org/t/coordinates-of-point-in-a-3d-image/4837 "2020-12-16T22:37:45Z")

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Dear All, Having a displayed 3D volume image (with interactor) and with a click with the mouse above the image, how it can be obtained that point (of the click) coordinate in the 3D referential? Thanks, Luís Gonçalves …

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## [Can I replace vtkRenderWindow to the window I created?](https://discourse.vtk.org/t/can-i-replace-vtkrenderwindow-to-the-window-i-created/4834)

<div class="topic-metadata">

**Author:** [@YAN\_LIU](https://discourse.vtk.org/u/YAN_LIU)\
**Replies:** 0\
**Last updated:** [December 16, 2020, 2:53pm UTC](https://discourse.vtk.org/t/can-i-replace-vtkrenderwindow-to-the-window-i-created/4834 "2020-12-16T14:53:17Z")

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I create a window by CreateWindowEx(), and get hWnd. Can I replace vtkRenderWindow to the window I created? I am new to vtk, but little to DirectX11. thanks!

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## [How to understand the depth of a display point?](https://discourse.vtk.org/t/how-to-understand-the-depth-of-a-display-point/4812)

<div class="topic-metadata">

**Author:** [@zhang-qiang-github](https://discourse.vtk.org/u/zhang-qiang-github)\
**Replies:** 5\
**Last updated:** [December 16, 2020, 12:08pm UTC](https://discourse.vtk.org/t/how-to-understand-the-depth-of-a-display-point/4812 "2020-12-16T12:08:41Z")

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I am reading the source code of VTK, and there is one concept make me confuzed. In the operation of camera (pan, zoom in/out), there is some code like: vtkCamera \*camera = this-\>CurrentRenderer-\>GetActiveCamera(); …

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## [MIME type glsl](https://discourse.vtk.org/t/mime-type-glsl/4770)

<div class="topic-metadata">

**Author:** [@Luis\_Carlos\_Carneiro](https://discourse.vtk.org/u/Luis_Carlos_Carneiro)\
**Replies:** 19\
**Last updated:** [December 16, 2020, 10:23am UTC](https://discourse.vtk.org/t/mime-type-glsl/4770 "2020-12-16T10:23:40Z")

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Dear All, My JavaScript Script is giving the following error in Firefox (in Windows): Loading module from “https://…/node\_modules/vtk.js/Sources/Rendering/OpenGL/glsl/vtkPolyDataVS.glsl” was blocked because of a disall…

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## [GetPointer vs ValueRange for typed data arrays](https://discourse.vtk.org/t/getpointer-vs-valuerange-for-typed-data-arrays/4826)

<div class="topic-metadata">

**Author:** [@jaswantp](https://discourse.vtk.org/u/jaswantp)\
**Replies:** 2\
**Last updated:** [December 16, 2020, 7:33am UTC](https://discourse.vtk.org/t/getpointer-vs-valuerange-for-typed-data-arrays/4826 "2020-12-16T07:33:27Z")

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I’m using vtkIdTypeArray to implement a half-edge data structure for 2D meshes. Once the faces are prepared, the connectivity and offsets array will be sent to vtkCellArray with (vtkCellArray::SetData(vtkIdTypeArray\*, vt…

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