3Delight is a 3D computer graphics software that runs on Microsoft Windows, macOS (both Intel and Apple Silicon) and Linux (both x86 and Graviton).
Developed by Illumination Research, it is both a photorealistic and NPR path tracing offline renderer based on its NSI API scene description and on Open_Shading_Language for shading.
It comes with supported, open source plug-in integrations for several DCC applications, such as Autodesk Maya, Houdini, Cinema4D, Katana, OpenUSD Hydra, and a democratic free license that allows for commercial use.
Until version 10 (2013), 3Delight primarily used the REYES algorithm but was also capable of doing ray tracing and global illumination.
In 2018 3DelightNSI 1.0 was introduced as a forward path tracer based on the new NSI API and using OSL for all shaders and light emitters.