OSPRay

OSPRay is an open-source, CPU-based ray tracing engine for scientific visualization and high-performance rendering. It enables physically based rendering of complex volumetric and geometric data and is designed to integrate with visualization toolkits and HPC workflows.

Architecturally, OSPRay provides a modular scene graph and rendering pipeline that supports geometry, volumes, lights, cameras, and materials. The core renderer leverages Embree for fast ray traversal and Open Shading Language (OSL) for programmable materials. It can render OpenVDB-style volume data as well as polygonal meshes, with transfer functions to map data values to color and opacity. The engine supports path tracing and other Monte Carlo rendering techniques to produce realistic illumination, including direct and global illumination through multiple bounces.

API and usage: OSPRay offers C++ and Python interfaces, enabling embedding in applications or use as a stand-alone renderer. It provides bindings and integration hooks for popular visualization systems, including ParaView and VTK-based pipelines, allowing users to drive scenes from existing workflows.

Performance and deployment: Optimized for multi-core CPUs, OSPRay supports parallel rendering and can operate in distributed settings to handle large datasets. It is designed to be extensible, with a range of optional components for shading models, lighting, and data sources.

Development and community: As an open-source project, OSPRay is maintained by a community of researchers and developers, with past involvement from major visualization and HPC organizations, and ongoing updates to support evolving data formats and workflows.