pub type MappedInstancePlan = Arc<FxHashMap<u32, (u32, u32)>>;Expand description
#1623 Phase 2 “don’t-bake” instancing plan: IfcRepresentationMap express id ⇒
(occurrence_count, template_item_id), where template_item_id is the SMALLEST
IfcMappedItem express id referencing that source (a deterministic, race-free
choice of which occurrence materializes its geometry as the shared template).
Only sources with occurrence_count >= 2 appear. Built ONCE from the file scan
and injected into every per-element / per-batch router via
GeometryRouter::enable_output_instancing. When a mapped item’s source is in
this plan AND the occurrence is a single-solid ordinary product, the
NON-template occurrences skip the per-occurrence vertex bake and emit an
instance-only placeholder (empty geometry carrying crate::mesh::InstanceMeta)
instead of a full materialized mesh — the ~29s / 43M-vertex materialize this
phase kills. None ⇒ every occurrence materializes (historical flat output,
byte-identical); exporters and the determinism harness never arm it.
Aliased Type§
pub struct MappedInstancePlan { /* private fields */ }