Tetra3D is a 3D hybrid software/hardware renderer library for Go, built on the Ebitengine game framework. It provides a full scene graph, camera system, lighting (point, directional, ambient), material system with PBR and custom Kage shaders, collision detection (AABB, sphere, capsule, triangle mesh), raycasting, animation (skeletal, morph target, texture), particle systems, grid-based pathfinding, and text rendering. The library is designed for retro-style 3D games (PS1/N64 era) with affine texture mapping and CPU vertex transforms. It includes a Blender add-on (tetra3d.py) for exporting scenes with game-specific properties (colliders, sectors, light volumes, animations) to GLTF. The repository has over 20 example programs demonstrating each feature, plus extensive unit tests and benchmarks. The codebase is actively maintained with a focus on performance (SIMD matrix multiplication, pooled buffers, dynamic batching). It is a library, not a standalone application, so users embed it in their Go projects using Ebitengine.