|Balken / Unterzug - Standard|
The standard beam,
IfcBeamStandardCase, defines a beam with certain constraints
for the provision of material usage, parameters and with certain
constraints for the geometric representation. The
IfcBeamStandardCase handles all cases of beams, that:
- have a reference to the IfcMaterialProfileSetUsage
defining the material profile association of the beam with the
cardinal point of its insertion relative to the local
- are consistent in using the correct cardinal point offset of
the profile as compared to the 'Axis' and 'Body' shape
- are based on a sweep of a planar profile, or set of profiles,
as defined by the IfcMaterialProfileSet
- have an 'Axis' shape representation with constraints provided
below in the geometry use definition
- have a 'Body' shape representation with constraints provided
below in the geometry use definition
- are extruded perpendicular to the profile definition plane
- have a start profile, or set of profiles, that is swept
- the sweeping operation can be linear extrusion, circular
rotation, or a sweep along a directrix
- the start profile, or set of profiles can be swept unchanged,
or might be changed uniformly by a taper definition
NOTE View definitions and implementer
agreements may further constrain the applicable geometry types,
e.g. by excluding tapering from an IfcBeamStandardCase
HISTORY New entity in IFC4.
The geometric representation of IfcBeamStandardCase is
defined using the following multiple shape representations for its
- Axis: A three dimensional open curve (subtype of
IfcBoundedCurve) defining the axis for the standard beam.
The cardinal point is determined by the beam axis.
- Body: A Swept Solid Representation or a CSG clipping
representation defining the 3D shape of the standard beam.
NOTE It is invalid to exchange a 'SurfaceModel',
'Brep', or 'MappedRepresentation' representation for the 'Body'
shape representation of an
Common Use Definitions
The following concepts are inherited at supertypes:
- IfcRoot: Identity, Revision Control
- IfcElement: Box Geometry, FootPrint Geometry, Body SurfaceOrSolidModel Geometry, Body SurfaceModel Geometry, Body Tessellation Geometry, Body Brep Geometry, Body AdvancedBrep Geometry, Body CSG Geometry, Mapped Geometry
- IfcBuildingElement: Surface 3D Geometry
- IfcBeam: Object Typing, Property Sets for Objects, Quantity Sets, Spatial Containment, Element Composition, Material Profile Set, Product Assignment
Material Profile Set Usage
The Material Profile Set Usage concept applies to this entity.
The IfcBeamStandardCase defines in addition that the
IfcBeamType should have a unique
IfcMaterialProfileSet, that is referenced by the
IfcMaterialProfileSetUsage that is assigned to all
occurrences of this IfcBeamType.
EXAMPLE Figure 165 illustrates alignment of cardinal points.
NOTE It has to be guaranteed that the use of IfcCardinalPointEnum is consistent to the placement of the extrusion body provided by IfcExtrudedAreaSolid.Position
NOTE The cardinal points 8 (top centre) and 6 (mid-depth right) are assigned according to the definition at IfcCardinalPointReference
Figure 165 — Beam cardinal points
EXAMPLE Figure 166 illustrates assignment of a composite profile by using IfcCompositeProfile for geometric representation and several IfcMaterialProfile's within the IfcMaterialProfileSet.
Figure 166 — Beam composite profiles
The Product Placement concept applies to this entity as shown in Table 87.
Table 87 — IfcBeamStandardCase Product Placement
The following restriction is imposed:
- The local placement shall provide the location and directions
for the standard beam, the x/y plane is the plane for the start
profile, and the z-axis is the extrusion axis for the beam body (in
case of rotation, the tangent direction).
Axis 3D Geometry
The Axis 3D Geometry concept applies to this entity as shown in Table 88.
|Axis||Curve3D||IfcBoundedCurve||Three-dimensional reference curve for the beam.|
Table 88 — IfcBeamStandardCase Axis 3D Geometry
The following additional constraints apply to the 'Axis'
representation, if the 'Body' shape representation has the
RepresentationType : 'SweptSolid':
EXAMPLE As shown in Figure 76, the axis shall be defined along the z axis of the object coordinate system. The axis representation can be used to represent the system length of a beam that may extent the body length of the beam.
Figure 167 — Beam axis representation
EXAMPLE As shown in Figure 77, the axis representation shall be used to represent the cardinal point as the offset between the 'Axis' and the extrusion path of the beam. The extrusion path is provided as IfcExtrudedAreaSolid.ExtrudedDirection and should be parallel to the 'Axis' and the z axis. It has to be guaranteed that the value provided by
IfcMaterialProfileSetUsage.CardinalPoint is consistent to the IfcExtrudedAreaSolid.Position.
Figure 168 — Beam axis cardinal point
Body SweptSolid Geometry
The Body SweptSolid Geometry concept applies to this entity.
The following additional constraints apply to the 'SweptSolid'
- Solid: IfcExtrudedAreaSolid,
IfcRevolvedAreaSolid shall be supported
- Solid Position : The IfcSweptAreaSolid.Position
shall exclusively been used to correspond to the cardinal point.
The x/y offset of the Position represents the cardinal
point offset of the profile against the axis. No rotation shall be
- Profile: All subtypes of
- Profile Position : For all single profiles, the
IfcParameterizedProfileDef.Position shall be NIL, or having
Location = 0.,0. and RefDirection = 1.,0.
- Extrusion: Perpendicular to the profile direction.
The IfcExtrudedAreaSolid.ExtrudedDirection shall be
- Orientation: The y-axis of the profile, as determined by
IfcSweptAreaSolid.Position.P shall point upwards. It
indicates the "role" of the beam, a role=0° means y-axis of
profile pointing upwards.
Figure 169 illustrates a standard geometric representation with cardinal point applied as 1 (bottom left).
The following interpretation of dimension parameter applies for rectangular beams with linear extrusions:
- IfcRectangleProfileDef.YDim interpreted as beam height
- IfcRectangleProfileDef.XDim interpreted as beam width
The following interpretation of dimension parameter applies for circular beams:
- IfcCircleProfileDef.Radius interpreted as beam radius.
Figure 169 — Beam body extrusion
Body AdvancedSweptSolid Geometry
The Body AdvancedSweptSolid Geometry concept applies to this entity.
The following additional constraints apply to the
'AdvancedSweptSolid' representation type:
Body Clipping Geometry
The Body Clipping Geometry concept applies to this entity.
The following constraints apply to the 'Clipping'
- Solid : see 'SweptSolid' geometric representation
- Solid Position : see 'SweptSolid' geometric
- Profile : see 'SweptSolid' geometric representation
- Profile Position : see 'SweptSolid' geometric
- Extrusion : see 'SweptSolid' geometric
- Orientation : see 'SweptSolid' geometric
- Boolean result: The IfcBooleanClippingResult
shall be supported, allowing for Boolean differences between the
swept solid (here IfcExtrudedAreaSolid) and one or several
IfcHalfSpaceSolid (or its subtypes).
Figure 170 illustrates a 'Clipping' geometric representation with use of IfcBooleanClippingResult between an IfcExtrudedAreaSolid and an IfcHalfSpaceSolid to create a clipped body, with cardinal point applied as 4 (mid-depth left)
Figure 170 — Beam body clipping
XSD Specification: <xs:element name="IfcBeamStandardCase" type="ifc:IfcBeamStandardCase" substitutionGroup="ifc:IfcBeam" nillable="true"/>
|HasMaterialProfileSetUsage|| : ||SIZEOF (QUERY(temp <* USEDIN(SELF, 'IFCKERNEL.IFCRELASSOCIATES.RELATEDOBJECTS') |
('IFCPRODUCTEXTENSION.IFCRELASSOCIATESMATERIAL' IN TYPEOF(temp)) AND
('IFCMATERIALRESOURCE.IFCMATERIALPROFILESETUSAGE' IN TYPEOF(temp.RelatingMaterial))
)) = 1;|
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