# Is vtkGUISupportQtOpenGL available in 8.2.0 with VTK\_RENDERING\_BACKEND=OpenGL2 ?

**URL:** <https://discourse.slicer.org/t/is-vtkguisupportqtopengl-available-in-8-2-0-with-vtk-rendering-backend-opengl2/4854>\
**Category:** Support\
**Tags:** build\
**Created:** [November 22, 2018, 11:52pm UTC](https://discourse.slicer.org/t/is-vtkguisupportqtopengl-available-in-8-2-0-with-vtk-rendering-backend-opengl2/4854 "2018-11-22T23:52:35Z")\
**Posts on this page:** 6\
**Page:** 1

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**Author:** ![yurivict](https://avatars.discourse-cdn.com/v4/letter/y/838e76/32.png) [@yurivict](https://discourse.slicer.org/u/yurivict)\
**Post date:** [November 22, 2018, 11:52pm UTC](https://discourse.slicer.org/t/is-vtkguisupportqtopengl-available-in-8-2-0-with-vtk-rendering-backend-opengl2/4854/1 "2018-11-22T23:52:35Z")

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I couldn’t build the 3dslicer project because 8.1.2 only has vtkGUISupportQtOpenGL when VTK\_RENDERING\_BACKEND=OpenGL, which is limiting in other respects.

Also see here: [http://vtk.1045678.n5.nabble.com/Find-reason-for-exclusion-of-vtkGUISupportQtOpenGL-in-build-output-td5738976.html](http://vtk.1045678.n5.nabble.com/Find-reason-for-exclusion-of-vtkGUISupportQtOpenGL-in-build-output-td5738976.html)

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**Author:** ![lassoan](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/lassoan/32/13_2.png) [@lassoan](https://discourse.slicer.org/u/lassoan)\
**Post date:** [November 22, 2018, 11:54pm UTC](https://discourse.slicer.org/t/is-vtkguisupportqtopengl-available-in-8-2-0-with-vtk-rendering-backend-opengl2/4854/2 "2018-11-22T23:54:51Z")

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Slicer requires OpenGL2 backend. By now most (maybe all) of the old OpenGL backend are implemented, there are huge improvements and new features in OpenGL2, and the old backend will be removed from VTK soon, so sticking to old OpenGL backend is not an option.

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**Author:** ![yurivict](https://avatars.discourse-cdn.com/v4/letter/y/838e76/32.png) [@yurivict](https://discourse.slicer.org/u/yurivict)\
**Post date:** [November 23, 2018, 12:23am UTC](https://discourse.slicer.org/t/is-vtkguisupportqtopengl-available-in-8-2-0-with-vtk-rendering-backend-opengl2/4854/3 "2018-11-23T00:23:33Z")

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Which VTK version do you build it with? I tried it with `8.1.2` and failed for the above reason.  
Is this fixed in `8.2.0` (which is still RC), should I try it? Or, otherwise, which vtk works?

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**Author:** ![lassoan](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/lassoan/32/13_2.png) [@lassoan](https://discourse.slicer.org/u/lassoan)\
**Post date:** [November 23, 2018, 12:56am UTC](https://discourse.slicer.org/t/is-vtkguisupportqtopengl-available-in-8-2-0-with-vtk-rendering-backend-opengl2/4854/4 "2018-11-23T00:56:57Z")

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Slicer downloads and builds all its dependencies, including VTK. Slicer configures VTK for optimal performance, for example uses TBB as SMP backend. So, I would strongly recommend to let Slicer build VTK for itself.

If you really want to configure Slicer to use your VTK build then use VTK 8.2.

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**Author:** ![yurivict](https://avatars.discourse-cdn.com/v4/letter/y/838e76/32.png) [@yurivict](https://discourse.slicer.org/u/yurivict)\
**Post date:** [November 23, 2018, 1:12am UTC](https://discourse.slicer.org/t/is-vtkguisupportqtopengl-available-in-8-2-0-with-vtk-rendering-backend-opengl2/4854/5 "2018-11-23T01:12:51Z")

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What you recommend would only work on Linux, because VTK doesn’t build on BSDs without patches.  
I want to create the FreeBSD port for slicer.

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**Author:** ![lassoan](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/lassoan/32/13_2.png) [@lassoan](https://discourse.slicer.org/u/lassoan)\
**Post date:** [November 23, 2018, 3:01am UTC](https://discourse.slicer.org/t/is-vtkguisupportqtopengl-available-in-8-2-0-with-vtk-rendering-backend-opengl2/4854/6 "2018-11-23T03:01:56Z")

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> [@yurivict](#):
>
> VTK doesn’t build on BSDs without patches

Please send your patches to VTK developers. Until the patches are integrated into the official VTK repository (and [Slicer’s VTK fork](https://github.com/Slicer/VTK/)), you can build Slicer with your own VTK fork: use Slicer’s VTK fork as a basis and specify set Slicer\_VTK\_GIT\_REPOSITORY and Slicer\_VTK\_GIT\_TAG in CMake when you configure your Slicer build to point to your fork.