# Instructions Wanted for Building VTK apps with Software Rendering on Windows
**URL:** https://discourse.vtk.org/t/instructions-wanted-for-building-vtk-apps-with-software-rendering-on-windows/16216
**Category:** Support
**Created:** [January 8, 2026, 4:09pm UTC](https://discourse.vtk.org/t/instructions-wanted-for-building-vtk-apps-with-software-rendering-on-windows/16216 "2026-01-08T16:09:40Z")
**Posts on this page:** 3
**Page:** 1
### Author:  [@niconiconi](https://discourse.vtk.org/u/niconiconi)
#### Post date: [January 8, 2026, 4:09pm UTC](https://discourse.vtk.org/t/instructions-wanted-for-building-vtk-apps-with-software-rendering-on-windows/16216/1 "2026-01-08T16:09:40Z")
I have a VTK application which I want to run on Windows 11 without a GPU. Currently, starting it causes an immediate crash due to lack of OpenGL:
```auto
Failed to load opengl32sw (The specified module could not be found.)
Failed to load and resolve WGL/OpenGL functions
qt.qpa.gl: Software OpenGL failed. Falling back to system OpenGL.
QOpenGLWindow::beginPaint: Failed to create context
QOpenGLWindow::beginPaint: Failed to make context current
2026-01-08 08:03:23.076 ( 0.117s) [18B4C5461F3729CD]vtkOpenGLRenderWindow.c:704 ERR| vtkGenericOpenGLRenderWindow (000001500D579BF0): GLEW could not be initialized: Missing GL version
QOpenGLFunctions created with non-current context
```
This application typically only renders relatively simple 3D geometries on the screen, so it had no problems working via LLVMpipe on Linux. I also tried providing an old copy of `opengl32sw.dll` prebuilt [by Qt here](https://download.qt.io/development_releases/prebuilt/llvmpipe/windows/), but GLEW still couldn’t be initialized, perhaps because the GL version was not supported?
Qt + VTK + OpenGL software rendering on Windows is an arcane topic and poorly documented and discussed anywhere online, so I have no idea how the same can be achieved on Windows. Does anyone know anything about it?
Thanks in advance.
---
### Author:  [@niconiconi](https://discourse.vtk.org/u/niconiconi)
#### Post date: [January 8, 2026, 4:40pm UTC](https://discourse.vtk.org/t/instructions-wanted-for-building-vtk-apps-with-software-rendering-on-windows/16216/2 "2026-01-08T16:40:28Z")
Problem solved.
You need these DLLs from Mesa. For 64-bit applications, make sure all DLLs are from Mesa 64-bit (`opengl32.dll` , like Win32, is a legacy name for both 32-bit and 64-bit systems):
- `libgallium_wgl.dll`
- `opengl32.dll`
- `mesadrv.dll`
- `dxil.dll`
The application should start directly.
The proprietary re-distributable DirectX IL file `dxil.dll` is needed, because Mesa by default uses the GLonD3D12 backend. In case you don’t want any proprietary libraries, you can omit the file and use the LLVMpipe backend instead. Start PowerShell with:
```auto
$env:GALLIUM_DRIVER=”llvmpipe”
```
In both cases, 3D graphics is working now.
More information can be found at: [GitHub - pal1000/mesa-dist-win: Pre-built Mesa3D drivers for Windows](https://github.com/pal1000/mesa-dist-win)
A good way to check is to use the “system-wide deployment” script to deploy Mesa system wide to see whether the application starts. If so, you can figure out the needed DLLs, drivers, and environmental variables later.
---
### Author:  [@mwestphal](https://discourse.vtk.org/u/mwestphal)
#### Post date: [January 8, 2026, 4:41pm UTC](https://discourse.vtk.org/t/instructions-wanted-for-building-vtk-apps-with-software-rendering-on-windows/16216/3 "2026-01-08T16:41:58Z")
[https://discourse.paraview.org/t/how-to-run-paraview-including-the-binary-release-using-mesa-on-windows/4321](https://discourse.paraview.org/t/how-to-run-paraview-including-the-binary-release-using-mesa-on-windows/4321)