appleseed vs Arnold

appleseed is a free, open source rendering engine for animation and visual effects, built around physically based global illumination. It is designed for individuals and small studios and runs on Windows, Linux, and macOS. Rendering methods include unidirectional path tracing, stochastic progressive photon mapping, light tracing, progressive and interactive rendering, and spectral rendering. For shading, it supports Open Shading Language and on-the-fly shader compilation. Production tools include motion blur, AOVs, Cryptomatte, adaptive sampling, denoising, and resumable render checkpoints. Native integrations are listed for Autodesk Maya, Autodesk 3ds Max, Blender, and Gaffer. It works with OBJ geometry and image formats including OpenEXR, TIFF, HDR, PNG, JPEG, and PSD. Developers can use C++ and Python APIs or extend the engine with external C++ plugins. The listed plan costs nothing and is under the MIT license. The download page lists version 2.1.0-beta, released September 21, 2019.

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