|Wand - Standard|
The IfcWallStandardCase defines a wall with certain
constraints for the provision of parameters and with certain
constraints for the geometric representation. The
IfcWallStandardCase handles all cases of walls, that are
- along the positive z axis of the wall object coordinate system,
- along the positve z axis of the global (world) coordinate
and have a single thickness along the path for each wall layer,
- parallel sides for straight walls
- co-centric sides for curved walls.
and have either:
- a straight line axis (straight wall), or
- a circular arc axis (round wall).
and shall not have
- aggregated components, that is, parts aggregated to a wall by IfcRelAggregates
- shape representation for 'Body' not being an extrusion, or clipped extrusion
The following parameter have to be provided:
- Wall height, taken from the depth of extrusion, provided by the geometric representation.
- Wall thickness, taken from the material layer set usage, attached to the wall
- Wall offset from axis, taken from the material layer set usage, attached to the wall
The IfcWallStandardCase requires the provision of the
wall axis either a straight line that is parallel to the x-axis of
the object coordinate system, or a circular arc where the tangent
at start is parallel to the x-axis of the object coordinate system.
The direction of the wall axis shall be the positive direction of
The material of the wall is defined by the
IfcMaterialLayerSetUsage and is attached by the
IfcRelAssociatesMaterial objectified relationship. It is
accessible by the inverse HasAssociations relationship.
The material layer set usage has to be given (enforced by where
HISTORY New entity in IFC2x.
The standard geometric representation of
IfcWallStandardCase is defined using the following
multiple shape representations for its definition:
- Axis: A two-dimensional open curve
(IfcBoundedCurve) defining the axis for the standard wall.
The material layer offset is measured from the wall axis.
- Body: A Swept Solid Representation or a CSG
representation defining the 3D shape of the standard wall
NOTE It is invalid to exhange a
'SurfaceModel', or '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
- IfcWall: Object Typing, Property Sets for Objects, Quantity Sets, Material Layer Set, Path Connectivity, Spatial Containment, Surface Geometry, Element Voiding, Product Assignment
Material Layer Set Usage
The Material Layer Set Usage concept applies to this entity.
Multi-layer walls can be represented by refering to several
IfcMaterialLayer's within the IfcMaterialLayerSet
that is referenced from the
Material information can also be given at the
IfcWallType, defining the common attribute data for all
occurrences of the same type. It is then accessible by the
inverse IsDefinedBy relationship pointing to
IfcSlabType.HasAssociations and via
The IfcWallType should then have a unique
IfcMaterialLayerSet, that is referenced by
the IfcMaterialLayerSetUsage assigned to all
occurrences of this IfcWallType.
Figure 221 illustrates material layer usage, where the following conventions shall be met:
- The reference coordinate system is the local coordinate system established by the ObjectPlacement of the IfcWallStandardCase.
- The reference axis is the axis defined by the IfcShapeRepresentation with RepresentationType='Axis' as one of the
Representation.Representations of the IfcWallStandardCase.
- The IfcMaterialLayerSetUsage.OffsetFromReferenceLine is given as a distance from this axis.
- The IfcMaterialLayerSetUsage.OffsetFromReferenceLine is the distance parallel to the reference axis and always within the base
(XY) plane of the reference coordinate system. A positve value of IfcMaterialLayerSetUsage.OffsetFromReferenceLine would
then point into the positive y-axis of the reference coordinate system.
- The IfcMaterialLayerSetUsage.DirectionSense defines how the IfcMaterialLayer's are assigned to the reference axis. POSITIVE means in direction to the positive y-axis of the reference coordinate system.
- The Thickness of each IfcMaterialLayer is provided starting from the OffsetFromReferenceLine and in the direction given by DirectionSense. It is applied without any gap or overlap between two consecutive layers. The TotalThickness of the IfcMaterialLayerSet is the sum of all layer thicknesses.
- The IfcMaterialLayerSetUsage.LayerSetDirection is always AXIS2.
Figure 221 — Wall material layers
Axis 2D Geometry
The Axis 2D Geometry concept applies to this entity as shown in Table 193.
|Axis||Curve2D||IfcBoundedCurve||The wall axis of the wall.|
Table 193 — IfcWallStandardCase Axis 2D Geometry
The wall axis is represented by a two-dimensional open curve
within a particular shape representation. The wall axis is used to
apply the material layer set usage parameter to the wall geometry.
EXAMPLE Figure 222 illustrates an axis representation for a straight wall. In case of a straight wall, the set of items shall
include a single geometric representation item of type IfcPolyline or IfcTrimmedCurve with the BasisCurve being an IfcLine. The IfcPolyline or IfcTrimmedCurve shall be parallel (here in a special case co-linear) to the x-axis
of the object coordinate system. The direction shall be identical to the direction of the x-axis.
Figure 222 — Wall axis straight
EXAMPLE Figure 223 illustrates an axis representation for a curved wall. In case of a curved wall, the set of items shall include
a single geometric representation item of type IfcTrimmedCurve. The curve shall have a BasisCurve of type IfcCircle. The tangent of the IfcTrimmedCurve shall be parallel at start to the x-axis of the object coordinate system. The direction shall be identical to the direction of the x-axis.
Figure 223 — Wall axis curved
The Product Placement concept applies to this entity as shown in Table 194.
Table 194 — IfcWallStandardCase Product Placement
The following restriction is imposed:
- The local placement shall provide the location and directions
for the standard wall, the x/y plane is the plane for the
profile, and the z-axis is the extrusion axis for the wall body.
Body SweptSolid Geometry
The Body SweptSolid Geometry concept applies to this entity.
The following additional constraints apply to the 'SweptSolid'
- Solid: IfcExtrudedAreaSolid is required,
- Profile: IfcArbitraryClosedProfileDef and
IfcRectangleProfileDef shall be supported.
- Extrusion: The profile shall be extruded vertically,
i.e., in the direction of the z-axis of the co-ordinate system of
the referred spatial structure element. It might be further
constraint to be in the direction of the global z-axis 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.
The profile of a wall is described in the ground view and extruded vertically. The profile (also identical with the foot print of the wall) is defined by the IfcArbitraryClosedProfileDef (excluding its subtypes). The profile is given with all wall connections already resolved.
Figure 224 illustrates a body representation for a straight wall. In case of a straight wall, the two sides of the profile shall be parallel to the wall axis, that is, the wall has a single unchanged thickness.
Figure 225 illustrates a body representation for a curved wall. In case of a curved wall, the two sides of the profile shall be parallel (with defined offset) to the wall axis, that is, the wall has a single unchanged thickness.
Figure 224 — Wall body extrusion straight
Figure 225 — Wall body extrusion curved
Body Clipping Geometry
The Body Clipping Geometry concept applies to this entity.
The following constraints apply to the 'Clipping'
- Solid: see standard geometric representation
- Profile: see standard geometric representation
- Extrusion: see standard geometric representation
- Boolean result: The IfcBooleanClippingResult
shall be supported, allowing for Boolean differences between the
swept solid (here IfcExtrudedAreaSolid) and one or several
IfcHalfSpaceSolid (or subtypes).
Figure 226 illustrates a clipping for a straight wall using an IfcPolygonalBoundedHalfSpace as SecondOperand in
Figure 227 illustrates a clipping for a curved wall using an IfcHalfSpaceSolid as SecondOperand in the
Figure 226 — Wall body clipping straight
Figure 227 — Wall body clipping curved
XSD Specification: <xs:element name="IfcWallStandardCase" type="ifc:IfcWallStandardCase" substitutionGroup="ifc:IfcWall" nillable="true"/>
|HasMaterialLayerSetUsage|| : ||SIZEOF (QUERY(temp <* USEDIN(SELF, 'IFCKERNEL.IFCRELASSOCIATES.RELATEDOBJECTS') |
('IFCPRODUCTEXTENSION.IFCRELASSOCIATESMATERIAL' IN TYPEOF(temp)) AND
('IFCMATERIALRESOURCE.IFCMATERIALLAYERSETUSAGE' IN TYPEOF(temp.RelatingMaterial))
)) = 1;|
|HasMaterialLayerSetUsage|| : ||
A valid instance of IfcWallStandardCase relies on the provision of an IfcMaterialLayerSetUsage.
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