Ragdoll preview engineering boundaries

BGS 1.1 includes a read-only engineering preview for measured Fallout 4 ragdoll data. It does not add HKX authoring, serialized physics edits, body-to-body collision, or a production Havok solver.

The preview includes measured rigid bodies and constraints, animation-to-ragdoll mapping, body frames and centres of mass, engineering inspection, sibling-skeleton fallback, drop/recover interaction, and constrained per-body gravity settle.

The constrained drop is intentionally deterministic and uses fixed 1/120 second steps, measured body and constraint frames, captured pivot offsets, ground contact, and measured ragdoll or hinge limit clamps. Existing regression tests define this behavior and must remain unchanged unless a new proof demonstrates a defect.

Ownership follow-up

SkeletonView currently owns both viewport interaction/rendering and the constrained-drop implementation. It is too large for continued feature growth. Before adding more ragdoll simulation or engineering controls, split the drop state and constraint math into focused helpers and keep SkeletonView as the viewport/controller boundary. That split should be behavior-preserving and validated by the existing ragdoll regression and UI lifecycle suites.

Do not expand the preview into inferred Havok semantics. New layouts, constraint behavior, or serialization rules require measured fixture evidence first.