6.1.3.48 IfcWallStandardCase

Wand - Standard
Mur 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 extruded vertically:

and have a single thickness along the path for each wall layer, i.e.:

and have either:

and shall not have

The following parameter have to be provided:

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 that x-axis.

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 rule).

HISTORY  New entity in IFC2x.

The standard geometric representation of IfcWallStandardCase is defined using the following multiple shape representations for its definition:

NOTE  It is invalid to exhange a 'SurfaceModel', or 'Brep' or 'MappedRepresentation' representation for the 'Body' shape representation of an IfcWallStandardCase.

Common Use Definitions

The following concepts are inherited at supertypes:

 Instance diagram

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 IfcMaterialLayerSetUsage

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 IfcRelAssociatesMaterial.RelatingMaterial.

The IfcWallType should then have a unique IfcMaterialLayerSet, that is referenced by the IfcMaterialLayerSetUsage assigned to all occurrences of this IfcWallType.

 

Material layer set and usage
EXAMPLE  Figure 220 illustrates assignment of IfcMaterialLayerSetUsage and IfcMaterialLayerSet to the wall type and the wall occurrence.

Figure 220 — Wall Standard Object Typing

 

Figure 221 illustrates material layer usage, where the following conventions shall be met:

roof slab material layer set

Figure 221 — Wall material layers



Axis 2D Geometry

The Axis 2D Geometry concept applies to this entity as shown in Table 193.
IdentifierTypeItemsDescription
AxisCurve2DIfcBoundedCurveThe 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.

 

straight wall axis
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

 
curved wall axis
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

 


Product Placement

The Product Placement concept applies to this entity as shown in Table 194.
TypeRelativeDescription
IfcLocalPlacementIfcLocalPlacementRelative placement according to position and rotation relative to container.
IfcLocalPlacement Absolute placement according to position and rotation of world coordinate system.
IfcGridPlacement Placement according to grid intersection.

Table 194 — IfcWallStandardCase Product Placement

The following restriction is imposed:



Body SweptSolid Geometry

The Body SweptSolid Geometry concept applies to this entity.

The following additional constraints apply to the 'SweptSolid' representation:

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.

straight wall body curved wall body

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' representation:

Figure 226 illustrates a clipping for a straight wall using an IfcPolygonalBoundedHalfSpace as SecondOperand in the IfcBooleanClippingResult.

Figure 227 illustrates a clipping for a curved wall using an IfcHalfSpaceSolid as SecondOperand in the IfcBooleanClippingResult.

straight wall clipping curved wall clipping

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"/>
 <xs:complexType name="IfcWallStandardCase">
  <xs:complexContent>
   <xs:extension base="ifc:IfcWall"/>
  </xs:complexContent>
 </xs:complexType>

EXPRESS Specification:

ENTITY IfcWallStandardCase
SUBTYPE OF IfcWall;
WHERE
HasMaterialLayerSetUsage : SIZEOF (QUERY(temp <* USEDIN(SELF, 'IFCKERNEL.IFCRELASSOCIATES.RELATEDOBJECTS') | ('IFCPRODUCTEXTENSION.IFCRELASSOCIATESMATERIAL' IN TYPEOF(temp)) AND ('IFCMATERIALRESOURCE.IFCMATERIALLAYERSETUSAGE' IN TYPEOF(temp.RelatingMaterial)) )) = 1;
END_ENTITY;

Link to EXPRESS-G diagram EXPRESS-G diagram

Formal Propositions:

HasMaterialLayerSetUsage : A valid instance of IfcWallStandardCase relies on the provision of an IfcMaterialLayerSetUsage.

Inheritance Graph:

ENTITY IfcWallStandardCase
ENTITY IfcRoot
GlobalId : IfcGloballyUniqueId;
OwnerHistory : OPTIONAL IfcOwnerHistory;
Name : OPTIONAL IfcLabel;
Description : OPTIONAL IfcText;
ENTITY IfcObjectDefinition
INVERSE
HasAssignments : SET OF IfcRelAssigns FOR RelatedObjects;
Nests : SET [0:1] OF IfcRelNests FOR RelatedObjects;
IsNestedBy : SET OF IfcRelNests FOR RelatingObject;
HasContext : SET [0:1] OF IfcRelDeclares FOR RelatedDefinitions;
IsDecomposedBy : SET OF IfcRelAggregates FOR RelatingObject;
Decomposes : SET [0:1] OF IfcRelAggregates FOR RelatedObjects;
HasAssociations : SET OF IfcRelAssociates FOR RelatedObjects;
ENTITY IfcObject
ObjectType : OPTIONAL IfcLabel;
INVERSE
IsDeclaredBy : SET [0:1] OF IfcRelDefinesByObject FOR RelatedObjects;
Declares : SET OF IfcRelDefinesByObject FOR RelatingObject;
IsTypedBy : SET [0:1] OF IfcRelDefinesByType FOR RelatedObjects;
IsDefinedBy : SET OF IfcRelDefinesByProperties FOR RelatedObjects;
ENTITY IfcProduct
ObjectPlacement : OPTIONAL IfcObjectPlacement;
Representation : OPTIONAL IfcProductRepresentation;
INVERSE
ReferencedBy : SET OF IfcRelAssignsToProduct FOR RelatingProduct;
ENTITY IfcElement
Tag : OPTIONAL IfcIdentifier;
INVERSE
FillsVoids : SET [0:1] OF IfcRelFillsElement FOR RelatedBuildingElement;
ConnectedTo : SET OF IfcRelConnectsElements FOR RelatingElement;
IsInterferedByElements : SET OF IfcRelInterferesElements FOR RelatedElement;
InterferesElements : SET OF IfcRelInterferesElements FOR RelatingElement;
HasProjections : SET OF IfcRelProjectsElement FOR RelatingElement;
ReferencedInStructures : SET OF IfcRelReferencedInSpatialStructure FOR RelatedElements;
HasOpenings : SET OF IfcRelVoidsElement FOR RelatingBuildingElement;
IsConnectionRealization : SET OF IfcRelConnectsWithRealizingElements FOR RealizingElements;
ProvidesBoundaries : SET OF IfcRelSpaceBoundary FOR RelatedBuildingElement;
ConnectedFrom : SET OF IfcRelConnectsElements FOR RelatedElement;
ContainedInStructure : SET [0:1] OF IfcRelContainedInSpatialStructure FOR RelatedElements;
ENTITY IfcBuildingElement
INVERSE
HasCoverings : SET OF IfcRelCoversBldgElements FOR RelatingBuildingElement;
ENTITY IfcWall
PredefinedType : OPTIONAL IfcWallTypeEnum;
ENTITY IfcWallStandardCase
END_ENTITY;

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