unity-2d-physics-lowlevellisted

# Unity Low-Level 2D Physics ## Retrieval Sources This system lives in the `UnityEngine.LowLevelPhysics2D` namespace (1581 ScriptReference pages locally) and, unlike many newer/preview-ish Unity APIs, it has a genuinely substantial Manual tree explaining it: `Manual/2d-physics-api/` contains 34 real explanatory pages (confirmed on disk, not just a bare ScriptReference dump), each carrying working code samples. So this skill is NOT purely signature-only — there is real conceptual documentation, and it is cited below alongside the exact ScriptReference member pages that were verified to exist. Every page in this table was confirmed present on disk before being cited (via `ls`, `find`, or direct `Read`). The official Unity example project referenced repeatedly across the Manual pages is `github.com/Unity-Technologies/PhysicsExamples2D` (an external resource, not verified locally, but named verbatim in the docs). | Source | Path | Use for | |--------|------|---------| | Namespace landing & TOC | `Manual/2d-physics-api/2d-physics-api-landing.html` | Entry point into the whole low-level 2D physics Manual tree; explicitly states this API does not use the Rigidbody 2D/Collider 2D component workflow | | Introduction & rationale | `Manual/2d-physics-api/2d-physics-api-introduction.html` | Box2D v3 origin, no-GameObject-required model, up to 64 CPU cores, 64 collision layers, struct-based/DOTS-friendly return types, compute-shader platform requirement | | Get started / workflow | `Ma