Keyframed curves, layered timelines, and a replay-proof event journal — deterministic animation on ticks.

NEXUS Animation is a deterministic animation foundation for Unity. Every sample, blend, and state transition resolves through typed systems with canonical ordering: the same inputs always produce the same output, and every event is journaled under a fixed key. Frame rate never touches animation logic — all windows and timers are simulation ticks.

- Curves and clips that validate themselves: Constant, Linear, and Smoothstep interpolation over canonically ordered keys; duplicate key times and duplicate track ids are rejected at construction.

- A layered timeline: instances schedule clips with Hold, Loop, and PingPong loop math; channels compose deterministically and later channels overwrite earlier ones.

- Blend spaces with per-mille weights: canonical normalization (unknown ids refused, NaN evaluates to 0) and pose blending in fixed motion order — the same weights always produce the same pose.

- A clip state machine: transitions gate on facts with immediate or timed switching; transitions scan in canonical order and the first satisfied condition wins — no hidden time, no randomness.

- Keyframed events with the (from, to] window rule: stepping fires each event exactly once.

- Replay-proof event journal: BeginEvent(key) refuses a repeated key BEFORE any state changes — replays become observable DuplicateEvent lines instead of silent double-fires. A rolling checksum folds every commit; print it and compare logs.

- Canonical NAM v1 snapshots: byte-stable JSON envelopes with a checksum folded over the member text the loader re-derives. Strict decode returns a typed taxonomy — Ok / BadMagic / BadVersion / Corrupt / ChecksumMismatch — and never throws for bad payloads.

- Editor tools: Create Animation Agent, the Timeline Designer (live sampling of the demo clip and blend), and About — all under Tools > NEXUS Animation.

Zero shaders, zero materials, zero rendering code. Unity 2021.3 LTS or newer, all render pipelines, all renderers. 93 EditMode tests included — run them in Test Runner right after import, no Play Mode needed.