# Odd Behavior when using OSPRay Pathtracer

**URL:** <https://discourse.paraview.org/t/odd-behavior-when-using-ospray-pathtracer/13249>\
**Category:** ParaView Support\
**Created:** [November 13, 2023, 10:39pm UTC](https://discourse.paraview.org/t/odd-behavior-when-using-ospray-pathtracer/13249 "2023-11-13T22:39:34Z")\
**Posts on this page:** 1\
**Showing post:** 3

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**Author:** ![Dave\_DeMarle](https://discourse.paraview.org/user_avatar/discourse.paraview.org/dave_demarle/32/27_2.png) [@Dave\_DeMarle](https://discourse.paraview.org/u/Dave_DeMarle)\
**Post date:** [November 28, 2023, 1:21am UTC](https://discourse.paraview.org/t/odd-behavior-when-using-ospray-pathtracer/13249/3 "2023-11-28T01:21:20Z")

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The ball of red lines is most likely the Client/Server widget state bug that @Sankhesh_Jhaveri re-fixed recently and should work in 5.12 since VTK’s CI covers it.

The remote is running MPI correct? If so, then see [this discussion](https://discourse.paraview.org/t/paraview-doesnt-perform-ray-tracing-ospray-correctly-with-mpi/11529) for the most likely cause. Although from the appearance it might be related to the [pathtracer background regression](https://gitlab.kitware.com/vtk/vtk/-/merge_requests/8577) that was recently fixed and should appear in 5.12.

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