Godot Engine – Multi-platform 2D and 3D game engine

A modern open source rendering engine for animation and visual effects

Hydra-enabled GPU path tracer that supports MaterialX and MDL

NanoRT, single header only modern ray tracing kernel.

AMD Radeon™ ProRender is a powerful physically-based path traced rendering engine that enables creative professionals to produce stunningly photorealistic images.

Filament is a real-time physically based rendering engine for Android, iOS, Windows, Linux, macOS, and WebGL2

c-ray is a small, simple path tracer written in C