Embree

Embree is a collection of high‑performance ray tracing kernels developed by Intel for CPU‑based rendering. It provides optimized, portable routines for ray-scene intersection and traversal, designed to maximize throughput on modern CPUs using SIMD instructions. Embree is open source and released under the Apache 2.0 license, intended for integration into rendering engines, visualization tools, and research projects that require fast ray tracing on the CPU.

The library offers a C API with C++ helpers and supports a variety of scene representations, including triangle meshes with motion blur and instancing. Its core concept is an acceleration structure, typically a bounding volume hierarchy (BVH), with multiple builder and traversal implementations tuned for different workloads. Embree provides kernels for different query types, such as primary rays, shadow/occlusion rays, and robust intersection tests, and emphasizes multi-threading and SIMD optimization (SSE, AVX, AVX-512 where available).

Platform support covers major desktop operating systems on x86-64 architectures, including Linux, Windows, and macOS. The project is actively developed by Intel and has an active ecosystem around it, including usage in other rendering systems and frameworks. Notable integrations include its use as a backend in OSPRay, Intel’s open-source ray tracing engine, and its adoption by various research and production rendering pipelines that require efficient CPU ray tracing.

Overall, Embree serves as a foundational, performance-focused toolkit for CPU-based ray tracing, enabling fast intersection tests and scalable rendering across a range of applications while remaining accessible under an open-source license.