Seeking Help with MPI Multi-Process Issues in OSPRay v3: PMPI_Finalize Error & Rendering Interaction Freeze

[zhanjun717]

Hi，
I’ve recently encountered some issues while using OSPRay, and I was hoping to get some help from the community.

Issue Description
Environment:

Operating System: Windows 11 x64
Processor: Intel(R) Core(TM) i9-14900HX 2.20 GHz
MPI Version: intel-mpi-2021.14.1.8.exe
OSPRay Version: v3

**Issue 1: I’m experiencing an issue after installing OSPRay v3 on Windows 11. The bin directory contains ospMPIDistribTutorialVolume.exe. Running the program with a single process works as expected。

but when attempting to run with multiple processes, I encounter the following error:**

Abort(810644750) on node 1 (rank 1 in comm 0): Fatal error in PMPI_Finalize: Unknown error class, error stack:
PMPI_Finalize(244)...............: MPI_Finalize failed
PMPI_Finalize(180)...............:
MPID_Finalize(1923)..............:
MPIDI_OFI_mpi_finalize_hook(1922):
MPIR_Bcast_intra_binomial(124)...:
MPIDIG_handle_unexpected(55).....: Message from rank 0 and tag 2 truncated; 4 bytes received but buffer size is 52
I would greatly appreciate any guidance on how to resolve this error when running with multiple processes. Could this issue be related to my MPI configuration or environment?

**Issue 2: When I build OSPRay from source and compile ospray/modules/mpi/tutorials/ospMPIDistribTutorialVolume.cpp, the resulting executable works fine in single-process mode.

However, in multi-process mode, the program can render the graphics, but the interaction window becomes unresponsive. Mouse interactions trigger an error, and the rendering window freezes. The error message is as follows:**

Mouse interactions trigger

OSPRay rank 1/2
OSPRay error: negative missing on 1, missingInCurrent = -1, expectedInNext = 0, currentGeneration = 1, tile = (448,192)
I would appreciate any insights or suggestions regarding the cause of the freezing and the unresponsive interaction window. Could there be a configuration or dependency issue I might have missed?

Help Requested:
For Issue 1, how can I avoid the PMPI_Finalize error when using multiple processes? Any advice on potential MPI-related problems or configuration fixes would be much appreciated.
For Issue 2, could you suggest why the rendering window freezes and becomes unresponsive in multi-process mode? Any pointers on possible configuration issues or missing dependencies would be very helpful.