Kray vs Mitsuba 3

Kray has no write-up on Specifiction yet; its figures are above.

Mitsuba 3 is a free, open-source, research-oriented system for forward and inverse light-transport simulation. It offers monochrome, RGB, and spectral rendering with optional polarization tracking, and computes derivatives with respect to camera pose, geometry, materials, textures, and volumes. Dr.Jit compiles rendering code for CPUs through LLVM and NVIDIA GPUs through CUDA and OptiX. Python integration supports development of materials, textures, and rendering algorithms, with documentation covering PyTorch interoperability. Installation is recommended through pip and requires Python 3.10 or later. Optional GPU computation requires NVIDIA driver 535 or later; parallel CPU computation optionally requires LLVM 18 or later. The project reports Linux x86_64, macOS aarch64 and x86_64, and Windows x86_64 support. Its plugins cover materials, light sources, and complete rendering algorithms. The Python package includes thirteen variants by default; more require compiling a custom Dr.Jit version with CMake. Tutorials, notebooks, how-to guides, and API and plugin references are provided.