# \#vtkwasm

**URL:** https://discourse.vtk.org/tag/vtkwasm/15.md

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

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## [What's New in VTK-wasm - Free Release Webinar](https://discourse.vtk.org/t/whats-new-in-vtk-wasm-free-release-webinar/16520)

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**Author:** [@NickBearup](https://discourse.vtk.org/u/NickBearup)\
**Replies:** 0\
**Last updated:** [August 25, 2026, 2:55pm UTC](https://discourse.vtk.org/t/whats-new-in-vtk-wasm-free-release-webinar/16520 "2026-08-25T14:55:39Z")

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The VTK team at Kitware will be hosting a free webinar on Thursday, September 3 from 12:00pm - 1:00pm ET covering the latest developments in VTK-wasm and how it can be used to bring high-performance VTK rendering directl…

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## [vtk-wasm webgl crashes with latest vtk-wasm docker images](https://discourse.vtk.org/t/vtk-wasm-webgl-crashes-with-latest-vtk-wasm-docker-images/16492)

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**Author:** [@RaMmer](https://discourse.vtk.org/u/RaMmer)\
**Replies:** 10\
**Last updated:** [August 2, 2026, 8:57pm UTC](https://discourse.vtk.org/t/vtk-wasm-webgl-crashes-with-latest-vtk-wasm-docker-images/16492 "2026-08-02T20:57:45Z")

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Hi, I have been observing regular vtk-wasm crashes with webgl losing context because of bad memory allocation as shown in the below picture. This was never occurring with the older docker images with version tag 9.6,…

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## [VTK.wasm 'ghost pixel' in browser](https://discourse.vtk.org/t/vtk-wasm-ghost-pixel-in-browser/16479)

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**Author:** [@HST](https://discourse.vtk.org/u/HST)\
**Replies:** 6\
**Last updated:** [July 15, 2026, 6:10am UTC](https://discourse.vtk.org/t/vtk-wasm-ghost-pixel-in-browser/16479 "2026-07-15T06:10:08Z")

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Hi, I started with VTK.wasm. My first goal was, display an empty blue screen. But the display contains white pixel from the bottom left to the top right corner. In a second step, I added a cone. The diagonal white pixe…

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## [Query with respect to WebGPU Rendering Backend in VTK WASM](https://discourse.vtk.org/t/query-with-respect-to-webgpu-rendering-backend-in-vtk-wasm/16355)

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**Author:** [@RaMmer](https://discourse.vtk.org/u/RaMmer)\
**Replies:** 2\
**Last updated:** [March 26, 2026, 10:31am UTC](https://discourse.vtk.org/t/query-with-respect-to-webgpu-rendering-backend-in-vtk-wasm/16355 "2026-03-26T10:31:43Z")

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Hello, I have been working with VTK WASM over the past few weeks and have been experimenting with the webgpu rendering backend. It works great for my use case which basically most of the time is around is just for visu…

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## [Trame + WASM: bind custom widget](https://discourse.vtk.org/t/trame-wasm-bind-custom-widget/16350)

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**Author:** [@kerim](https://discourse.vtk.org/u/kerim)\
**Replies:** 3\
**Last updated:** [March 23, 2026, 9:37am UTC](https://discourse.vtk.org/t/trame-wasm-bind-custom-widget/16350 "2026-03-23T09:37:42Z")

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Hi, I wrote custom widget in C++ fork of VTK 9.6 and now I’m trying to port it to Trame local view using WASM approach. My approach is to build VTK WASM, install trame-vtklocal package with VTK\_WASM\_DIR\_OVERRIDE env va…

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## [Error: WebGPU canvas selector with vtkWebAssemblyHardwareWindow fails for the official Geometry Viewer Emscripten Example](https://discourse.vtk.org/t/error-webgpu-canvas-selector-with-vtkwebassemblyhardwarewindow-fails-for-the-official-geometry-viewer-emscripten-example/16313)

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**Author:** [@RaMmer](https://discourse.vtk.org/u/RaMmer)\
**Replies:** 4\
**Last updated:** [March 5, 2026, 4:21am UTC](https://discourse.vtk.org/t/error-webgpu-canvas-selector-with-vtkwebassemblyhardwarewindow-fails-for-the-official-geometry-viewer-emscripten-example/16313 "2026-03-05T04:21:13Z")

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Hi, I have noticed that the WebGPU canvas selector for the official example Geometry Viewer fails as it defaults to the default canvas selection id canvas instead of vtk-3d-canvas. These are the commands I have used to…

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## [Error: could not instantiate classes like vtkXMLPolyDataReader with the vtk.wasm module](https://discourse.vtk.org/t/error-could-not-instantiate-classes-like-vtkxmlpolydatareader-with-the-vtk-wasm-module/16275)

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**Author:** [@RaMmer](https://discourse.vtk.org/u/RaMmer)\
**Replies:** 6\
**Last updated:** [February 17, 2026, 12:50am UTC](https://discourse.vtk.org/t/error-could-not-instantiate-classes-like-vtkxmlpolydatareader-with-the-vtk-wasm-module/16275 "2026-02-17T00:50:06Z")

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Hi, I was working on a development project with react and typescript bundled with vite using vtk js for visualisation. However I had issues with it and since moved to handle the same with vtk-wasm instead. I have set u…

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## [how to read STEP file in vtk wasm](https://discourse.vtk.org/t/how-to-read-step-file-in-vtk-wasm/16128)

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**Author:** [@blocky](https://discourse.vtk.org/u/blocky)\
**Replies:** 1\
**Last updated:** [January 30, 2026, 3:33pm UTC](https://discourse.vtk.org/t/how-to-read-step-file-in-vtk-wasm/16128 "2026-01-30T15:33:00Z")

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Hi everyone, I’m currently trying to read STEP files in VTK WASM. Based on some previous posts, I recompiled the vtk-master version, set VTK\_MODULE\_ENABLE\_VTK\_IOOCCT to YES, and compiled a 32-bit version of OpenCASCADE …

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## [A tale of 2.5 UIs](https://discourse.vtk.org/t/a-tale-of-2-5-uis/16135)

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**Author:** [@Joe\_Tristano](https://discourse.vtk.org/u/Joe_Tristano)\
**Replies:** 3\
**Last updated:** [November 12, 2025, 4:59pm UTC](https://discourse.vtk.org/t/a-tale-of-2-5-uis/16135 "2025-11-12T16:59:32Z")

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Vtk ui Hello Im writing for those who may find themselves in the same situation as well as for any guidance from the experts I started down a path of writing an interactive vtk application. I am inspired by fui (iro…

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## [CameraOrientationWidget Slow rendering with WASM](https://discourse.vtk.org/t/cameraorientationwidget-slow-rendering-with-wasm/16099)

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**Author:** [@Joe\_Tristano](https://discourse.vtk.org/u/Joe_Tristano)\
**Replies:** 0\
**Last updated:** [October 19, 2025, 12:30pm UTC](https://discourse.vtk.org/t/cameraorientationwidget-slow-rendering-with-wasm/16099 "2025-10-19T12:30:39Z")

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Hi, I have a small trame app where I want some spatial awareness on the screen. Interaction and rotation of my actors is very fast without any spatial awareness widgets. When I add CameraOrientationWidget or if I add …

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## [Trame in subprocess doesnt render wasm. Possible websocket wslink issue](https://discourse.vtk.org/t/trame-in-subprocess-doesnt-render-wasm-possible-websocket-wslink-issue/16087)

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**Author:** [@Joe\_Tristano](https://discourse.vtk.org/u/Joe_Tristano)\
**Replies:** 2\
**Last updated:** [October 10, 2025, 9:44pm UTC](https://discourse.vtk.org/t/trame-in-subprocess-doesnt-render-wasm-possible-websocket-wslink-issue/16087 "2025-10-10T21:44:03Z")

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Based on some reading, and this thread pvd , vtu , vti files with vtk wasm I decided to try and Start trame in a sub process. When I do file open, it starts trame with the appropriate file. When I open a new file, it sh…

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## [VTK 9.5.0 WebAssembly 64-bit build fails with BigInt conversion error](https://discourse.vtk.org/t/vtk-9-5-0-webassembly-64-bit-build-fails-with-bigint-conversion-error/15794)

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**Author:** [@leehyeonseop](https://discourse.vtk.org/u/leehyeonseop)\
**Replies:** 6\
**Last updated:** [July 21, 2025, 1:13pm UTC](https://discourse.vtk.org/t/vtk-9-5-0-webassembly-64-bit-build-fails-with-bigint-conversion-error/15794 "2025-07-21T13:13:22Z")

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Hello, I’m trying to build VTK 9.5.0 with WebAssembly 64-bit support following the official documentation, but I’m encountering a BigInt conversion error during the build process. Special Note: Initially, the build was …

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## [How can I render volume with vtk webAssembly](https://discourse.vtk.org/t/how-can-i-render-volume-with-vtk-webassembly/13737)

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**Author:** [@leo](https://discourse.vtk.org/u/leo)\
**Replies:** 7\
**Last updated:** [May 26, 2025, 11:59am UTC](https://discourse.vtk.org/t/how-can-i-render-volume-with-vtk-webassembly/13737 "2025-05-26T11:59:36Z")

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I’m trying to render a volume using vtk webAssembly, but it doesn’t work. I would like to know if vtk webAssembly supports volume rendering, and if not, do I have any alternatives?

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## [VTK/WASM: Push client camera state to server (i.e. update server camera to match the client camera)](https://discourse.vtk.org/t/vtk-wasm-push-client-camera-state-to-server-i-e-update-server-camera-to-match-the-client-camera/15444)

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**Author:** [@uv382](https://discourse.vtk.org/u/uv382)\
**Replies:** 1\
**Last updated:** [March 31, 2025, 3:23am UTC](https://discourse.vtk.org/t/vtk-wasm-push-client-camera-state-to-server-i-e-update-server-camera-to-match-the-client-camera/15444 "2025-03-31T03:23:48Z")

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@jaswantp Hi Jaswant, I know we spoke about this earlier but I forgot to ask specifically how it’s done. In VTK/WASM, the active camera on the server does not stay synchronized with the active camera on the frontend unl…

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## [Vtk.js with vtk.wasm usage](https://discourse.vtk.org/t/vtk-js-with-vtk-wasm-usage/15427)

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**Author:** [@antonskrebkov](https://discourse.vtk.org/u/antonskrebkov)\
**Replies:** 0\
**Last updated:** [March 25, 2025, 2:53pm UTC](https://discourse.vtk.org/t/vtk-js-with-vtk-wasm-usage/15427 "2025-03-25T14:53:30Z")

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Hi! I faced a lot of vtk.js restrictions (mostly lack of necessary methods, filters etc) and decided to expand application with vtk wasm but only as computation power without any rendering. Before that the flask backend…

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## [In VTK+WASM, how do I make the camera zoom on right click?](https://discourse.vtk.org/t/in-vtk-wasm-how-do-i-make-the-camera-zoom-on-right-click/15338)

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**Author:** [@uv382](https://discourse.vtk.org/u/uv382)\
**Replies:** 1\
**Last updated:** [March 5, 2025, 1:46am UTC](https://discourse.vtk.org/t/in-vtk-wasm-how-do-i-make-the-camera-zoom-on-right-click/15338 "2025-03-05T01:46:09Z")

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Normally in VTK, if you wanted to modify what each mouse button does, you would create a subclass of vtkInteractorStyle with all your custom events described. For example, in Python, if you wanted the camera to zoom eve…

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## [How do I call renderer.GetActiveCamera() in JavaScript using VTK/WASM?](https://discourse.vtk.org/t/how-do-i-call-renderer-getactivecamera-in-javascript-using-vtk-wasm/15242)

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**Author:** [@uv382](https://discourse.vtk.org/u/uv382)\
**Replies:** 6\
**Last updated:** [February 9, 2025, 10:04pm UTC](https://discourse.vtk.org/t/how-do-i-call-renderer-getactivecamera-in-javascript-using-vtk-wasm/15242 "2025-02-09T22:04:52Z")

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I am trying to access the current camera object from the frontend (JavaScript) in a VTK/WASM project. In the “pure-js” example in the trame-vtklocal repository, there is a file called main.js. For the purposes of this q…

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## [I need to visualize the contact areas between multiple .stl files](https://discourse.vtk.org/t/i-need-to-visualize-the-contact-areas-between-multiple-stl-files/14883)

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**Author:** [@HARIPRASATH\_Y\_S](https://discourse.vtk.org/u/HARIPRASATH_Y_S)\
**Replies:** 2\
**Last updated:** [November 16, 2024, 4:52am UTC](https://discourse.vtk.org/t/i-need-to-visualize-the-contact-areas-between-multiple-stl-files/14883 "2024-11-16T04:52:42Z")

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i need to see the intersecting area in different colour, i dont know how to do it, is there any way in vtk.js to do that functionality. To view the contact area between the .stl files, if possible can you suggest with an…

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## [Issues I encountered while compiling with the vtk-wasm-sdk Docker.](https://discourse.vtk.org/t/issues-i-encountered-while-compiling-with-the-vtk-wasm-sdk-docker/14322)

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**Author:** [@Behtgod](https://discourse.vtk.org/u/Behtgod)\
**Replies:** 7\
**Last updated:** [October 8, 2024, 1:29pm UTC](https://discourse.vtk.org/t/issues-i-encountered-while-compiling-with-the-vtk-wasm-sdk-docker/14322 "2024-10-08T13:29:04Z")

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When I used the Docker image of kitware/vtk-wasm-sdk, I encountered various problems. I followed the Usage on DockerHub, downloaded the examples, and then proceeded to compile them. I am using the Windows platform, and…

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## [Multiple render windows for vtkWasm](https://discourse.vtk.org/t/multiple-render-windows-for-vtkwasm/14246)

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**Author:** [@Jens\_Munk\_Hansen](https://discourse.vtk.org/u/Jens_Munk_Hansen)\
**Replies:** 1\
**Last updated:** [September 25, 2024, 7:17pm UTC](https://discourse.vtk.org/t/multiple-render-windows-for-vtkwasm/14246 "2024-09-25T19:17:03Z")

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Hi Guys I have a working setup using two vtkWebAssembly....Windows. It is super nasty. I stop and resume the message loop when the mouse enters a window. Here, I set all interactors to nullptr and set my interactor to t…

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## [FourPaneViewer (now in WASM)](https://discourse.vtk.org/t/fourpaneviewer-now-in-wasm/14306)

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**Author:** [@Jens\_Munk\_Hansen](https://discourse.vtk.org/u/Jens_Munk_Hansen)\
**Replies:** 5\
**Last updated:** [July 29, 2024, 1:48pm UTC](https://discourse.vtk.org/t/fourpaneviewer-now-in-wasm/14306 "2024-07-29T13:48:20Z")

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Hi Guys Working on a good way to wrap VTK to WASM. Right now, I am facing a problem that I had earlier with the FourPaneViewer after updating to VTK 9, the cursor actors disappears. My old fix, which works for OpenGL wa…

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## [Error of Qt&vtk for Wasm](https://discourse.vtk.org/t/error-of-qt-vtk-for-wasm/13336)

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**Author:** [@leo](https://discourse.vtk.org/u/leo)\
**Replies:** 2\
**Last updated:** [July 23, 2024, 6:17am UTC](https://discourse.vtk.org/t/error-of-qt-vtk-for-wasm/13336 "2024-07-23T06:17:24Z")

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I build successfully with Qt&vtk for wasm, but I can’t display it and get the following error. Can anyone help me with suggestions? Thank you in advance!

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## [Resizing canvas using interactor (WASM with threading)](https://discourse.vtk.org/t/resizing-canvas-using-interactor-wasm-with-threading/13962)

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**Author:** [@Jens\_Munk\_Hansen](https://discourse.vtk.org/u/Jens_Munk_Hansen)\
**Replies:** 3\
**Last updated:** [June 4, 2024, 3:15pm UTC](https://discourse.vtk.org/t/resizing-canvas-using-interactor-wasm-with-threading/13962 "2024-06-04T15:15:49Z")

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I have replicated the setup from vtkWasmBenchmarks, where I use vtkRenderWindowInteractor::InteractorManagesTheEventLoop = false. It works perfectly. I followed the latest build instructions for VTK+WASM (updated a week…

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## [VTK WASM](https://discourse.vtk.org/t/vtk-wasm/11650)

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**Author:** [@mazurkin.daniel](https://discourse.vtk.org/u/mazurkin.daniel)\
**Replies:** 6\
**Last updated:** [April 16, 2024, 8:50pm UTC](https://discourse.vtk.org/t/vtk-wasm/11650 "2024-04-16T20:50:34Z")

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Hello, I am assembling tools from 3D Slicer for use in the browser. After assembling the tools, it complains about shaders. Could you please advise me on how to modify shader code if I start my project using the command …

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## [Subcategories for Glance, VolView, vtk.js and vtk.wasm?](https://discourse.vtk.org/t/subcategories-for-glance-volview-vtk-js-and-vtk-wasm/11302)

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**Author:** [@cory.quammen](https://discourse.vtk.org/u/cory.quammen)\
**Replies:** 7\
**Last updated:** [February 22, 2024, 2:53am UTC](https://discourse.vtk.org/t/subcategories-for-glance-volview-vtk-js-and-vtk-wasm/11302 "2024-02-22T02:53:15Z")

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Hi folks, What do we think of adding subcategories under the Web category for vtk.js, vtk.wasm, Glance, and VolView? Glance and VolView are applications based on vtk.js, and there isn’t a community forum for them, and w…

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## [Does anyone use vtkSDL2RenderWindowInteractor outside of webassembly?](https://discourse.vtk.org/t/does-anyone-use-vtksdl2renderwindowinteractor-outside-of-webassembly/12386)

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**Author:** [@jaswantp](https://discourse.vtk.org/u/jaswantp)\
**Replies:** 2\
**Last updated:** [September 28, 2023, 2:07pm UTC](https://discourse.vtk.org/t/does-anyone-use-vtksdl2renderwindowinteractor-outside-of-webassembly/12386 "2023-09-28T14:07:20Z")

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I’m thinking of renaming vtkSDL2RenderWindowInteractor → vtkWebAssemblyRenderWindowInteractor because SDL2 is an implementation detail. We might want to change the implementation to use something WASI specific in the fut…

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## [Trouble following WASM tutorial (Not working)](https://discourse.vtk.org/t/trouble-following-wasm-tutorial-not-working/12331)

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**Author:** [@scottm](https://discourse.vtk.org/u/scottm)\
**Replies:** 10\
**Last updated:** [September 22, 2023, 8:08pm UTC](https://discourse.vtk.org/t/trouble-following-wasm-tutorial-not-working/12331 "2023-09-22T20:08:16Z")

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Hi, I am trying to follow along with the tutorial on the following page: Building using emscripten for WebAssembly - VTK documentation I used the VTK v9.2.6 and dockcross/web-wasm:20230222-162287d, I followed all steps…

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## [Slowly rendering widget from 3D Slicer in wasm.](https://discourse.vtk.org/t/slowly-rendering-widget-from-3d-slicer-in-wasm/11778)

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**Author:** [@mazurkin.daniel](https://discourse.vtk.org/u/mazurkin.daniel)\
**Replies:** 4\
**Last updated:** [July 28, 2023, 1:59pm UTC](https://discourse.vtk.org/t/slowly-rendering-widget-from-3d-slicer-in-wasm/11778 "2023-07-28T13:59:15Z")

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Hello, I have built a widget display from 3D Slicer in WebAssembly (you can check out the instructions at this link Instruction by 3dSlicer - Google Docs), but when rendering, it all happens quite slowly. Can you please …

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## [\[VTK Wasm\] Axes do not show up when using axes actor](https://discourse.vtk.org/t/vtk-wasm-axes-do-not-show-up-when-using-axes-actor/11917)

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**Author:** [@adityaDas](https://discourse.vtk.org/u/adityaDas)\
**Replies:** 3\
**Last updated:** [July 27, 2023, 7:42am UTC](https://discourse.vtk.org/t/vtk-wasm-axes-do-not-show-up-when-using-axes-actor/11917 "2023-07-27T07:42:21Z")

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We have been trying to use VTK Axes actors to display an axes triad on the scene. In this term, we have followed the instructions stated in this particular example: examples.vtk.org/site/Cxx/Interaction/CallBack/. How…

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## [ReadPixel slowly web gl](https://discourse.vtk.org/t/readpixel-slowly-web-gl/11877)

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**Author:** [@mazurkin.daniel](https://discourse.vtk.org/u/mazurkin.daniel)\
**Replies:** 0\
**Last updated:** [July 5, 2023, 8:30am UTC](https://discourse.vtk.org/t/readpixel-slowly-web-gl/11877 "2023-07-05T08:30:00Z")

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Hello, there is a problem when using ReadPixel for transferring 3D Slicer tools to the browser. This issue was discovered through graphics execution profiling. What are the possible solutions to this problem?

[Next page](https://discourse.vtk.org/tag/vtkwasm/15.md?match_all_tags=true&page=1&tags%5B%5D=vtkwasm)