v0.1.0-preview.5

First public release. The 2D engine and the shared core are the supported surface; the 3D engine ships as a preview marked [Experimental("OPHYS0002")]. A user guide is in docs/guide/.

Moved results: 2D worlds are bit-identical to preview.4 for the same inputs. 3D worlds move: an exact capsule-against-box closest pair replaces the general path when the shapes are apart, and the joint solver computes each joint's block inverse once per substep. Convex hulls built from inputs that were near-coplanar or noisy can differ (see below). Snapshot layout is unchanged.

• Allocation-free from the first step, also under load and with several threads. Warmup() now prepares every pool thread (including threads an earlier world started) for the narrowphase and batch queries, runs the pool's parallel paths of a throwaway world whatever their size, and stocks the island body-list pool for the world's body count. Before, a pile that kept merging and splitting islands allocated a few hundred bytes at about one step in a few hundred, and the first step of a multi-threaded 3D world allocated on the calling thread. ComputeHash() is documented as streaming (it always was: no snapshot copy is made).
• Breaking: CharacterDef.SlopeLimit and Character.SlopeLimit are SlopeLimitRadians (2D and 3D); the unit is in the name. The value and its default are unchanged.
• world.BodyCount, world.Bodies, world.CharacterCount, world.Characters (2D and 3D, identical): count and foreach over the live bodies and characters in slot order with a struct enumerator that allocates nothing.
• The 3D engine is [Experimental("OPHYS0002")]: every public type in RecursiveAI.OnePhysics.Physics3D. Using it raises the diagnostic until you suppress it (#pragma warning disable OPHYS0002 or <NoWarn>); its API and its results may change between previews. The 2D engine and the shared types are not marked.
• The package now carries the README.
• Convex hulls contain their input points. ConvexHull3D.Build now decides face visibility with exact predicates, rescans every input point once the hull is built, and checks each merged face against every point, undoing a merge that would leave a point outside. Every input point is inside every face within the documented tolerance, or the build is refused with HullBuildException; before, some near-coplanar inputs gave a hull that left a point outside by up to a few centimetres. Building is about 20% slower on hostile inputs.
• 3D Restore refuses damaged contact and vehicle state, and a step reports a runaway sleeping body. A snapshot holding a saved contact impulse no solver step could have produced (it would launch the bodies out of the world in one step), or a vehicle wheel with an absurd sprung mass or wheel or engine speed, is refused with SnapshotFormatException naming the value, and the world is unchanged. A sleeping body far from the origin is now checked at the start of every step (BodyOutOfBoundsException, world unchanged), and a vehicle wheel whose top lies just outside the supported range finds no ground instead of failing the step. Valid worlds are bit-identical.
• 3D, faster at 8 threads: solve stages split into one task per constraint batch and the worker count follows the average stage width (terrain scenes about 1.5–1.8× faster at 8 threads); results do not depend on the thread count, as before.
• 3D integration runs lane-wide with a bit-identical scalar twin.
• Package metadata, symbols (.snupkg) and Source Link for the public repository.