Definition from IAI: A beam (IfcBeam) is a horizontal structural member. It represents a horizontal, or nearly horizontal structural member designed to carry loads.
The quantities relating to the beam are defined by the IfcElementQuantity and attached by the IfcRelDefinesByProperties. The following quantities are foreseen, but will be subjected to the local standard of measurement:
| Name | Description | Value Type |
| CrossSectionArea | Total area of the cross section (or profile) of the beam. The exact definition and calculation rules depend on the method of measurement used. | IfcAreaQuantity |
| BeamVolume | Total volume of the beam. The exact definition and calculation rules depend on the method of measurement used. | IfcVolumeQuantity |
HISTORY New entity in IFC Release 1.0
ISSUE See issue log for changes made in IFC Release 1.5.1 See issue and change log for changes made in IFC Release 2x.
Geometry Use Definitions:
The geometric representation of IfcBeam is given by the IfcProductDefinitionShape, allowing multiple geometric representation. Included are:
Local Placement
The local placement for IfcBeam is defined in its supertype IfcProduct. It is defined by the IfcLocalPlacement, which defines the local coordinate system that is referenced by all geometric representations.
- The PlacementRelTo relationship of IfcLocalPlacement shall point (if given) to the local placement of the same IfcSpatialStructureElement, which is used in the ContainedInStructure inverse attribute, or to a spatial structure element at a higher level, referenced by that.
- If the relative placement is not used, the absolute placement is defined within the world coordinate system.
Standard Geometric Representation using Swept Solid Representation
The standard geometric representation of IfcBeam is defined using the swept solid representation. The RepresentationType attribute of IfcShapeRepresentation should have the value 'SweptSolid'. The following additional constraints apply to the swept solid representation:
- Solid: IfcExtrudedAreaSolid shall be supported
- Profile: IfcRectangleProfileDef and IfcCircleProfileDef shall be supported
- Extrusion: The profile shall be extruded horizontally, i.e., parallel to the XY Plane of the co-ordinate system of the referred spatial structure element. It might be further constraint to be parallel to the global XY Plane in implementers agreements. The extrusion axis shall be perpendicular to the swept profile, i.e. pointing into the direction of the z-axis of the Position of the IfcExtrudedAreaSolid.
EXAMPLE for standard geometric representation.
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The following interpretation of dimension parameter applies for circular beams: |
Advanced Geometric Representation using CSG Representation
The advanced geometric representation of IfcBeam is defined using the Swept Solid or CSG geometry. The RepresentationType attribute of IfcShapeRepresentation should have the value 'SweptSolid' or 'CSG'. The following constraints apply to the advanced representation:
- Solid: see standard geometric representation,
- Profile: IfcRectangleProfileDef, IfcCircleProfileDef, IfcIshapeProfileDef and IfcArbitraryProfileDef shall be supported.
- Extrusion: All extrusion directions shall be supported.
- Boolean result: The IfcBooleanClippingResult shall be supported, allowing for Boolean differences between the swept solid (here IfcExtrudedAreaSolid) and one or several IfcHalfSpaceSolid.
EXAMPLEs for advanced geometric representation
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Use of non-perpendicular extrusion to create the IfcExtrudedAreaSolid. |
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Use of IfcBooleanClippingResult between an IfcExtrudedAreaSolid and an IfcHalfSpaceSolid to create a clipped body. |