Class DemeshSession

Release the session's own GeometryProcessor (a shared one is untouched).

Write the lighter IFC: original bytes + tessellated replacements for every currently simplified element. Does not mutate session state — the user can keep simplifying and export again.

The coordinate-frame shift of the meshes this session works with (the supplied originShift, or the session's own load's after self-meshing). A viewer whose scene uses a different anchor (multi-model federation with a shared RTC) translates render-mesh origins by the difference.

The n heaviest elements by triangle count — demesh candidates for the UI. Requires meshes (supplied or produced on first simplify).

The level currently applied to an element (0 = untouched).

The ORIGINAL mesh records of expressIds (session frame, untouched by any simplification) — lets a viewer restore an element's real geometry in the scene after reset(). Meshes the source on first use.

Forget the simplification state for expressIds (all when omitted). The caller restores the elements' original meshes in the scene.

Express ids currently carrying simplified geometry.

Simplify expressIds at level, or — when level is omitted — one level past each element's current one (the button behavior: press, press again, ...; capped at 5).