Element Catalog

Every element follows the same contract: a typed spec in millimeters, an analytically built brepjs solid in local coordinates, and placement applied downstream via IfcLocalPlacement. The parse*Spec functions validate specs standalone; the add* methods validate, build, and store.

Element	Method	Notes
Wall	addWall	Length along axisX, openings cut via addDoor / addWindow
Slab	addSlab	FLOOR / ROOF / LANDING / BASESLAB; slab openings via parseSlabOpeningInput
Beam	addBeam	Profile extruded along axisX by length
Column	addColumn	Profile extruded along axisZ by height
Roof	addRoof	Flat slab, or shaped (shed / gable / hip / dome) when pitch is present
Curtain wall	addCurtainWall	Panel and mullion grid
Space	addSpace	Room volumes for zoning and COBie
Footing / pile	addFooting / addPile	Foundations
Stair	addStair	One or more flights, each a stepped sawtooth solid with its own placement
Ramp	addRamp	Flights like stairs, inclined slabs
Railing	addRailing	Posts + rails with infill: 'POSTED', or a single swept panel
Covering	addCovering	Finishes: flooring, cladding, ceilings
Proxy	addProxy	Anything else, carrying arbitrary brepjs geometry

Doors and windows are not free-standing: addDoor / addWindow take a host wall, cut the opening as a boolean void, and wire IfcRelVoidsElement + IfcRelFillsElement.

Profiles

Beams and columns extrude a profile, one vocabulary shared by both:

• Core: RECTANGULAR, CIRCULAR, I_BEAM (with optional root filletRadius)
• Extended: L / T / U / Z / C shapes, asymmetric I, ellipse, trapezium, hollow rectangular and circular sections, and arbitrary polygons with voids

Every named profile emits its own parametric IFC profile def, extended kinds included: IfcRectangleProfileDef / IfcCircleProfileDef / IfcIShapeProfileDef for the core three, and IfcLShapeProfileDef, IfcTShapeProfileDef, IfcUShapeProfileDef, IfcZShapeProfileDef, IfcCShapeProfileDef, IfcAsymmetricIShapeProfileDef, IfcEllipseProfileDef, IfcTrapeziumProfileDef, IfcRectangleHollowProfileDef and IfcCircleHollowProfileDef for the rest. The section stays editable parametric data in the exported file rather than a baked outline.

Only the two point-list kinds serialize as outlines, which is inherent to what they are: ARBITRARY_CLOSED becomes IfcArbitraryClosedProfileDef and ARBITRARY_WITH_VOIDS becomes IfcArbitraryProfileDefWithVoids.

On the brepjs side, extendedProfileToFace builds the section face for the solid and extendedProfileArea gives closed-form areas for takeoff.

Shaped roofs

pitch opts a roof into shaped geometry for its predefinedType: a right-trapezoid prism (shed), a house-pentagon prism (gable), a convex-hull hip with the ridge along the longer side, or a faceted dome. Without pitch the roof is a flat slab whatever the type says. Shaped roofs and posted railings serialize as tessellated bodies; everything else stays parametric IfcExtrudedAreaSolid.

Placement and display

Element geometry is unplaced template geometry. A wall's solid starts at the local origin and runs along local +X regardless of where the wall stands; origin / axisX / axisZ live in the spec and become IfcLocalPlacement. When you need world-placed solids (display, clash checks), placedSolids(element) returns fresh, caller-owned solids already transformed, so the scene you render matches the IFC you export. Most elements return one solid; stairs and ramps return one per flight, and curtain walls return their panels and mullions. Elements that are purely relational (doors, windows, groups, spatial containers) return an empty list rather than an error.

Data layers

Beyond geometry, elements carry: property sets from IFC pset templates with typed measures, quantity sets for takeoff, materials (simple, layer sets, profile sets), classification references (Uniclass, OmniClass, and friends), surface styles, and zone / system membership. Stable identity comes from deterministic GUIDs: deriveIfcGuid for content-derived ids, newIfcGuid for random ones.