Bevy vs Flax Engine

Bevy is a free, open-source game engine built in Rust for 2D and 3D games, visualizations, interfaces, and other graphical applications. It uses a custom Entity Component System, with components represented as Rust structs and systems as Rust functions. The engine includes 2D and 3D rendering, a composable render graph, skeletal and morph-target animation, scene loading, hot reloading, UI, and audio playback. Its 2D renderer supports sprites, texture atlases, cameras, materials, custom shaders, and render pipelines. The 3D renderer includes lights, shadows, meshes, materials, cameras, and glTF loading. The ECS-driven UI framework uses flex-box layout and can be composed in code or scenes. Scene changes can update running applications; hot reloading currently covers scenes, textures, and meshes. Bevy targets Windows, macOS, Linux, web, iOS, and Android, and is available through crates.io with cargo add bevy. Users choose MIT or Apache 2.0 licensing, with no license fees or sales cuts. It remains in development, with possible missing features, sparse documentation, and breaking API changes about every three months.

Flax Engine is a 3D game engine written in C++ and C#, with visual scripting and full Editor source code available. It supports C++, C#, and visual scripting, with hot-reloading for both programming languages in the Editor. Rendering features include real-time global illumination, reflections using custom software ray tracing, and GPU lightmap baking. World-building tools cover terrain, foliage, fog, nested prefabs, level streaming, and large-world 64-bit coordinates. Multiplayer projects can use low- and high-level networking APIs. Its Online system supports services such as Steam, Xbox Live, and PlayStation Network for profiles, friends, achievements, presence, and cloud saves. Supported targets include Windows, Linux, Android, iOS, macOS, web, PlayStation 4 and 5, Xbox One and Series, and Nintendo Switch. Web support is experimental and lacks C# scripting, video playback, and some other engine features. NDA-protected platform support is excluded from the public repository. The engine is free for non-commercial or educational use; commercial releases pay a 4% royalty on earnings exceeding $250,000 per calendar quarter.