IfcWallStandardCase
Definition from buildingSMART: The standard wall
(IfcWallStandardCase) defines a wall with certain constraints for the
provision of parameter and with certain constraints for the geometric
representation. The IfcWallStandardCase handles all cases of walls, that
have a single thickness along the path, i.e.:
 parallel sides for straight walls
 cocentric sides for curved walls.
The following parameter shall be given:
 Wall height, taken from the depth of extrusion, provided by the
geometric representation.
 Wall thickness, taken from the material layer set, attached to the
wall
 Wall offset from axis, taken from the material layer set, attached to
the wall
The material of the wall is defined by the
IfcMaterialLayerSetUsage and attached by the
IfcRelAssociatesMaterial. It is accessibly by the inverse
HasAssociations relationship. The material layer set has to be given
(enforced by where rule).
HISTORY New entity in IFC
Release 2x.
Property Set Use Definition:
The property sets relating to the IfcWallStandardCase are defined
at the supertype IfcWall.
Quantity Use Definition:
The quantities relating to the IfcWallStandardCase are defined at
the supertype IfcWall.
Geometry Use Definitions:
The geometric representation of IfcWallStandardCase is given by
the IfcProductDefinitionShape, allowing multiple geometric
representation. Included are:
Local Placement
The use of local placement is defined at the supertype
IfcWall.
Geometric Representation
The standard geometric representation of IfcWallStandardCase is
defined using the following multiple shape representations for its
definition:
 Axis: A twodimensional 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
First representation: Curve2D representation of wall axis
The wall axis is represented by a twodimensional open curve within a
particular shape representation. The wall axis is used to apply the parameter
to the wall geometry. The following attribute values shall be used
IfcShapeRepresentation shall have the following values:
 RepresentationIdentifier : 'Axis'
 RepresentationType : 'Curve2D'

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. 

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. 
Second representation: SweptSolid or Clipping representation of wall
body
The body of the IfcWallStandardCase is defined by using
'SweptSolid' representation for walls without clippings or 'Clipping'
representation for walls with clippings (e.g. under sloped roof slabs).
IfcShapeRepresentation shall have the following values:
 RepresentationIdentifier : 'Body'
 RepresentationType : 'SweptSolid' or 'Clipping'
SweptSolid representation
The standard geometric representation (for body) of
IfcWallStandardCase is defined using the 'SweptSolid' representation.
The following additional constraints apply to the swept solid
representation:
 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 zaxis of the coordinate system of the referred spatial
structure element. It might be further constraint to be in the direction of the
global zaxis in implementers agreements. The extrusion axis shall be
perpendicular to the swept profile, i.e. pointing into the direction of the
zaxis 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.
 In case of a straight wall the two sides of the
profile shall be parallel to the wall axis, i.e. the wall has a single
unchanged thickness.


 In case of a curved wall the two sides of the
profile shall be parallel (with defined offset) to the wall axis, i.e. the wall
has a single unchanged thickness.

The advanced geometric representation (for body) of
IfcWallStandardCase is defined using the 'Clipping' representation. The
following additional constraints apply to the swept solid representation:
 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).

Example of clipping using an
IfcPolygonalBoundedHalfSpace as SecondOperand in the
IfcBooleanClippingResult. 

Example of clipping using an
IfcHalfSpaceSolid as SecondOperand in the
IfcBooleanClippingResult. 
EXPRESS specification:



WR1

:

SIZEOF (QUERY(temp <* USEDIN(SELF, 'IFCKERNEL.IFCRELASSOCIATES.RELATEDOBJECTS') 
('IFCPRODUCTEXTENSION.IFCRELASSOCIATESMATERIAL' IN TYPEOF(temp)) AND
('IFCMATERIALRESOURCE.IFCMATERIALLAYERSETUSAGE' IN TYPEOF(temp.RelatingMaterial))
)) = 1;




Formal Propositions:
WR1

:

The IfcWallStandard relies on the provision of an IfcMaterialLayerSetUsage.

Inheritance graph

ENTITY IfcWallStandardCase;

