wtf is godot-box3d?

Godot Box3D is an extension for the Godot game engine that swaps in a different physics engine called Box3D in place of Godot's own built in 3D physics system. It is built as a GDExtension, which is a way of adding native code features to Godot 4 without modifying the engine itself, and it is designed as a drop in replacement, meaning a project can switch over to it through a project setting rather than a rewrite. The project structure follows an earlier extension called godot-jolt, which first showed this approach of swapping Godot's physics backend was possible. The author is upfront that this is early and experimental, since Box3D itself is a young physics engine and this extension is still a work in progress with missing pieces and rough edges. Even so, a solid range of features already work: rigid, static, and kinematic bodies, common collision shapes like boxes, spheres, capsules, and both convex and concave meshes, area overlap detection with gravity and damping overrides, and several physics query types such as ray casts and shape casts. It also supports the motion testing that Godot's CharacterBody3D relies on, plus pin, hinge, and slider joints. A small test project with demo and stress test scenes is included. Several things are explicitly not done yet, including certain shape types Box3D itself does not support, some joint types, soft body physics, per pair collision exceptions, and support for platforms beyond Linux, Windows, and macOS. Performance tuning and documentation are also still pending. To build it, you need Godot 4.3 or newer and the CMake build tool. Building produces a library file that you copy into your own Godot project along with a small extension descriptor file, after which you select Box3D as the physics server in your project settings. The author is actively looking for contributors, whether that means tackling missing features, reporting bugs with a scene that reproduces them, running benchmarks, or writing documentation. Both this extension and the underlying Box3D engine are released under the MIT License, a permissive license that allows free use, including commercial use, as long as the copyright notice is kept.