/**
 * Spatial hierarchy builder - builds the project/site/building/storey tree.
 *
 * Single source for spatial-hierarchy construction. There are two entry points
 * over one shared `buildNode`:
 *   - `build(...)`     fresh parse: extracts storey elevations from the source
 *                      buffer. Throws if there is no IfcProject.
 *   - `buildFromCache` cache restore: no source buffer, so storey elevations
 *                      stay empty. Returns undefined if there is no IfcProject.
 * Both paths get the same cycle guard, aggregate-descendant storey mapping, and
 * spatial-child promotion, so they cannot drift.
 */
import type { EntityTable, StringTable, RelationshipGraph, SpatialHierarchy } from '@ifc-lite/data';
import type { EntityRef } from './types.js';
export declare class SpatialHierarchyBuilder {
    /**
     * Fresh-parse build. Extracts storey elevations from the source buffer.
     * Throws if no IfcProject is present.
     *
     * @param lengthUnitScale - Scale to convert IFC length values to meters (e.g. 0.001 for millimeters).
     */
    build(entities: EntityTable, relationships: RelationshipGraph, _strings: StringTable, source: Uint8Array, entityIndex: {
        byId: {
            get(expressId: number): EntityRef | undefined;
        };
    }, lengthUnitScale?: number): SpatialHierarchy;
    /**
     * Cache-restore build. No source buffer, so storey elevations stay empty
     * (`getStoreyByElevation` returns null). Returns undefined if no IfcProject.
     */
    buildFromCache(entities: EntityTable, relationships: RelationshipGraph): SpatialHierarchy | undefined;
    private assemble;
    private buildNode;
    /**
     * Extract elevation from an IfcBuildingStorey. Elevation is attribute index 9
     * in both IFC2x3 and IFC4 (GlobalId, OwnerHistory, Name, Description,
     * ObjectType, ObjectPlacement, Representation, LongName, CompositionType,
     * Elevation).
     */
    private extractElevation;
    /**
     * Resolve a storey's elevation from its ObjectPlacement, used as a fallback when
     * the Elevation attribute is null. Walks
     *   IfcBuildingStorey.ObjectPlacement (IfcLocalPlacement)
     *     -> RelativePlacement (IfcAxis2Placement3D)
     *       -> Location (IfcCartesianPoint).Coordinates[2]
     * i.e. the storey's Z relative to its parent spatial container, which matches
     * the semantics of the Elevation attribute and avoids folding in any site-level
     * georeferencing Z. Returns the raw (unscaled) Z, or undefined when the chain
     * can't be resolved.
     */
    private extractPlacementElevation;
}
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