Ospray artefacts for surfaces when using MPI
When rendering using OSPRay and with multpiple ranks we can see some artefacts at the border of the data split (see first image). This seems to be an issue of precision with the border of object in the depth buffer computed by OSPRay (see 2nd and 3rd images). One may need to download the images and zoom to see the artefacts for the depth buffers. Tested with OSPRay 2.4.X and 2.5.0.
Steps to reproduce :
- launch server as
mpirun -n X pvserver
(in the images X=2) - launch
paraview
and connect to the server - create a sphere
- activate ray-tracing (either ospray raytracer or ospray pathtracer)
- move camera and see artefacts
This was not visible before the update to OSPRay 2.X : vtk/vtk!7031 (merged).
@demarle could you confirm/refute that this is an OSPRay issue ?
Also alongside these rectangle-shaped artefacts we can see a pretty large gap between the two geometries, this may (or not) be related.