ZEngine — Animation Blend Trees and State Machines

Priority: Next-year plan Status: Design — depends on a skeletal animation system that does not yet exist. Depends on: animation asset/runtime and skinning contracts.

Direction

Blend trees and state machines are authored pose-selection/blending layers above a validated skeletal-animation base. The old node, manager, component, and evaluator definitions were sketches; they do not establish a runtime layout, capacity, or public API.

Required design

• Define asset schema/versioning for states, parameters, transitions, blend spaces, masks, additive/reference poses, events, sync groups, and stable clip references.
• Decide evaluation clock, deterministic behavior, root-motion authority, transition interruption, update budget, pose-cache ownership, and error/overflow fallback.
• Make runtime state serializable only where it is product-authored. Pose buffers, GPU palettes, and transient evaluation handles remain derived state.
• Coordinate editor preview, authoring transactions, Play isolation, asset reload, and scene round-trip with the animation and scene-document contracts.

Acceptance gates

• Test transition, blend-space, additive, interruption, event, and root-motion behavior against an explicit clock and reference poses.
• Validate malformed/obsolete graphs, missing clips, reload, entity deletion, and budget exhaustion without corrupting a render payload.
• Use visual and performance reference gates on supported hardware before exposing the feature as production-ready.