IFC base quantities

Base Quantities are dimensions and values that are taken from the geometry of the model and that can be transferred to exchange partners.

You can transfer the following base quantities:

IFC class	Attribute	Explanation
IfcWallStandardCase (= multi-layer wall of constant width)	Width	The thickness of the entire wall or of an individual layer
	Length	Length of the center line of the wall
	GrossSideArea	Gross area of wall returned by a longitudinal section of the center axis, without subtracting openings
	NetSideArea	Net area of wall returned by a longitudinal section of the center axis, with (interior) openings being subtracted
	GrossVolume	GrossSideArea x width
	NetVolume	NetSideArea x width
	Height	Wall height (walls of constant height only)
	GrossFootprintArea	Length x width (of the wall or of individual layers)

IfcOpeningElement (= opening of rectangular outline)	Depth	Matches the thickness of the element to which the opening belongs
	Height	Approximate value of the opening height
	Width	Approximate value of the opening width

IfcOpeningElement (= opening as a freeform area of constant thickness)	Depth	Matches the thickness of the element to which the opening belongs
	Area	Matches the area of the opening

IfcOpeningElement (= opening as a freeform area of variable thickness)	Volume	Matches the volume of the opening