# Building ParaView 5.12.1 from Source (VisRTX not using GPU)
**URL:** https://discourse.paraview.org/t/building-paraview-5-12-1-from-source-visrtx-not-using-gpu/16141
**Category:** ParaView Support
**Created:** [February 10, 2025, 4:36pm UTC](https://discourse.paraview.org/t/building-paraview-5-12-1-from-source-visrtx-not-using-gpu/16141 "2025-02-10T16:36:45Z")
**Posts on this page:** 8
**Page:** 1
### Author:  [@Adnan\_Hafeez](https://discourse.paraview.org/u/Adnan_Hafeez)
#### Post date: [February 10, 2025, 4:36pm UTC](https://discourse.paraview.org/t/building-paraview-5-12-1-from-source-visrtx-not-using-gpu/16141/1 "2025-02-10T16:36:46Z")
I am reaching out regarding an issue we are encountering after building ParaView from source on our HPC system. We opted for a source installation to tailor the build to our hardware specifications rather than using the pre-built binaries.
– System Specifications
We have the following dependencies installed:
GCC: 10
CUDA: 11.8
TBB: Installed
OpenMPI: 5.0.0
– Build Configuration
We used the following CMake command to build ParaView:
```auto
cmake -GNinja -DCMAKE_INSTALL_PREFIX=${PREFIX} -DPARAVIEW_USE_QT=ON -DPARAVIEW_USE_CUDA=ON -DPARAVIEW_USE_MPI=ON \
-DCMAKE_CUDA_ARCHITECTURES="70;80" -DPARAVIEW_USE_PYTHON=ON -DVTK_SMP_IMPLEMENTATION_TYPE=TBB \
-DVTK_USE_VISRTX=ON -DCMAKE_BUILD_TYPE=Release ..
```
After installation, when launching ParaView, we expect to see a message indicating that VisRTX is using the GPU (e.g., _“ParaView VisRTX Using GPU”_). However, we don’t, and it seems that ParaView does not recognize our GPU.
We are using an NVIDIA Tesla V100, which works properly with other CUDA applications, including PyTorch and TensorFlow.
Could you please advise on potential misconfigurations or additional steps required to enable GPU support in our setup?
Thank you
---
### Author:  [@mwestphal](https://discourse.paraview.org/u/mwestphal)
#### Post date: [February 10, 2025, 4:38pm UTC](https://discourse.paraview.org/t/building-paraview-5-12-1-from-source-visrtx-not-using-gpu/16141/2 "2025-02-10T16:38:59Z")
> [@Adnan\_Hafeez](#):
>
> when launching ParaView, we expect to see a message indicating that VisRTX is using the GPU (e.g., _“ParaView VisRTX Using GPU”_)
VisRTX is only used when using Raytracing, which is not enabled by default in ParaView, di you try enabling ?
> it seems that ParaView does not recognize our GPU.
Please copy the content of Help → About here.
Thanks,
---
### Author:  [@Adnan\_Hafeez](https://discourse.paraview.org/u/Adnan_Hafeez)
#### Post date: [February 10, 2025, 9:16pm UTC](https://discourse.paraview.org/t/building-paraview-5-12-1-from-source-visrtx-not-using-gpu/16141/3 "2025-02-10T21:16:15Z")
Thank you for your prompt response. Yes, I did enable ray tracing at the time of compilation using the CMAKE variable -DPARAVIEW\_ENABLE\_RAYTRACING=ON. I also have Ospray version 2.8.0 installed here. Perhaps my issue is I’m using ospray (which appears to be for CPUs only?)
Should I be using a different backend for ray tracing, and if yes, please let me know how I can do that?
Here is a copy of my “About”
Client Information:
Version: 5.12.1
VTK Version: 9.3.20231030
Qt Version: 5.12.11
vtkIdType size: 64bits
Embedded Python: On
Python Library Path: /usr/lib64/python3.6
Python Library Version: 3.6.8 (default, Jul 29 2024, 11:15:47) [GCC 8.5.0 20210514 (Red Hat 8.5.0-18)]
Python Numpy Support: On
Python Numpy Path: /usr/lib64/python3.6/site-packages/numpy
Python Numpy Version: 1.14.3
Python Matplotlib Support: Off
Python Testing: Off
MPI Enabled: On
Disable Registry: Off
Test Directory:
Data Directory:
SMP Backend: TBB
SMP Max Number of Threads: 1
OpenGL Vendor: Mesa/X.org
OpenGL Version: 4.5 (Core Profile) Mesa 22.3.0
OpenGL Renderer: llvmpipe (LLVM 15.0.7, 256 bits)
Accelerated filters overrides available: No
Connection Information:
Remote Connection: No
---
### Author:  [@mwestphal](https://discourse.paraview.org/u/mwestphal)
#### Post date: [February 11, 2025, 7:15am UTC](https://discourse.paraview.org/t/building-paraview-5-12-1-from-source-visrtx-not-using-gpu/16141/4 "2025-02-11T07:15:03Z")
> Yes, I did enable ray tracing at the time of compilation using the CMAKE variable -DPARAVIEW\_ENABLE\_RAYTRACING=ON.
You enabled it in the build, that doesnt mean it is turned on at runtime.
> [@Adnan\_Hafeez](#):
>
> OpenGL Vendor: Mesa/X.org
You are indeed not using your GPU, what is the output of `glxinfo` ?
---
### Author:  [@Adnan\_Hafeez](https://discourse.paraview.org/u/Adnan_Hafeez)
#### Post date: [February 11, 2025, 3:20pm UTC](https://discourse.paraview.org/t/building-paraview-5-12-1-from-source-visrtx-not-using-gpu/16141/5 "2025-02-11T15:20:24Z")
Hello Mathieu, I think what I need to do is build VisRTX from source and link it with ParaView during it’s build process. What I’m trying right now is working on VisRTX dependencies (OptixSDK and ANARI SDK installation).
Once that’s complete, I should be able to point VISRTX\_DIR to the correct location and re-try building ParaView with Raytracing and Ospray enabled. I will let you know what the outcome of that is.
---
### Author:  [@Adnan\_Hafeez](https://discourse.paraview.org/u/Adnan_Hafeez)
#### Post date: [February 12, 2025, 2:03pm UTC](https://discourse.paraview.org/t/building-paraview-5-12-1-from-source-visrtx-not-using-gpu/16141/6 "2025-02-12T14:03:32Z")
Is there a constraint as to which VisRTX and Anari versions can be used with Paraview?
---
### Author:  [@Adnan\_Hafeez](https://discourse.paraview.org/u/Adnan_Hafeez)
#### Post date: [February 15, 2025, 1:43pm UTC](https://discourse.paraview.org/t/building-paraview-5-12-1-from-source-visrtx-not-using-gpu/16141/7 "2025-02-15T13:43:13Z")
@mwestphal I tried to build ParaView against Anari version 0.2.0, VisRTX version 0.4.0 and Optix 7.4.0 and got the following cmake error:
```auto
CMake Error at VTK/Rendering/RayTracing/CMakeLists.txt:100 (message):
VisRTX 0.2.0 and above are intended to be used via the ANARI interface.
See https://gitlab.kitware.com/vtk/vtk/-/merge_requests/10324 for progress.
```
Could you please help me understand what sort of requirements does ParaView have on Anari? I’m clearly using a VisRTX version greater than 0.2.0 here.
Thank you
---
### Author:  [@Lucas\_Givord](https://discourse.paraview.org/u/Lucas_Givord)
#### Post date: [February 17, 2025, 10:15am UTC](https://discourse.paraview.org/t/building-paraview-5-12-1-from-source-visrtx-not-using-gpu/16141/8 "2025-02-17T10:15:32Z")
Hello @Adnan_Hafeez,
Sadly it is not possible to build ParaView 5.12.1 with VisRTX \> 0.2.0 (that’s why in the binary release available in [paraview.org](http://paraview.org), the visrtx used is the version 0.1.6).
VisRTX has been completely rewrite, with Anari, in 0.2.0 and newer version. So to be able to use VisRTX, we need to support Anari. Fortunately, VTK has a first version of Anari which start to be implemented before the release of the 5.12.1 of ParaView. This is why you have this message from the CMakeLists.
Currently, you can used VTK master with Anari (and so being able to use visrtx \> 0.2.0).
However, you can’t build it with ParaView Master, there is an ongoing work from Sankhesh and me to be able to use Anari in ParaView, the merge request is here: [https://gitlab.kitware.com/paraview/paraview/-/merge\_requests/6573](https://gitlab.kitware.com/paraview/paraview/-/merge_requests/6573)
we aim to support Anari in ParaVew Master in a near future.
I hope the current state of visrtx, anari and ParaView is clearer now