Intel® Embree is a collection of high-performance ray tracing kernels,
developed at Intel. The target users of Intel® Embree are graphics
application engineers who want to improve the performance of their
photo-realistic rendering application by leveraging Embree's
performance- optimized ray tracing kernels. The kernels are optimized
for the latest Intel® processors with support for SSE, AVX, AVX2, and
AVX-512 instructions.

Note to 32-bit users: This is x86_64 only, due to its use of CPU
instructions that don't exist on 32-bit x86 processors.

Intel® Embree supports runtime code selection to choose the traversal
and build algorithms that best matches the instruction set of your CPU.
We recommend using Intel® Embree through its API to get the highest
benefit from future improvements. Intel® Embree is released as Open
Source under the Apache 2.0 license.

Intel® Embree supports applications written with the Intel® SPMD
Program Compiler (ISPC, https://ispc.github.io/) by also providing
an ISPC interface to the core ray tracing algorithms. This makes it
possible to write a renderer in ISPC that automatically vectorizes and
leverages SSE, AVX, AVX2, and AVX-512 instructions. ISPC also supports
runtime code selection, thus ISPC will select the best code path for
your application.

Intel® Embree contains algorithms optimized for incoherent workloads
(e.g. Monte Carlo ray tracing algorithms) and coherent workloads (e.g.
primary visibility and hard shadow rays).

The single-ray traversal kernels of Intel® Embree provide high
performance for incoherent workloads and are very easy to integrate
into existing rendering applications. Using the stream kernels, even
higher performance for incoherent rays is possible, but integration
might require significant code changes to the application to use the
stream paradigm. In general for coherent workloads, the stream mode
with coherent flag set gives the best performance.

Intel® Embree also supports dynamic scenes by implementing
high-performance two-level spatial index structure construction
algorithms.

In addition to the ray tracing kernels, Intel® Embree provides some
Embree Tutorials to demonstrate how to use the Embree API.

Optional dependency: Intel® Threading Building Blocks (TBB) & Intel®
SPMD Program Compiler (ISPC)