IfcWall
Definition from ISO 67071:1989: Vertical construction usually in masonry or in concrete which bounds or subdivides a construction works and fulfils a load bearing or retaining function.
Definition from IAI: The wall represents a vertical construction that bounds or subdivides spaces. Wall are usually vertical, or nearly vertical, planar elements, often designed to bear structural loads. A wall is however not required to be load bearing. The IFC specification provides two entities for wall occurrences:
HISTORY New entity in IFC Release 1.0, the entity has changed in IFC Release 2x.
Type Use Definition
IfcWall (or the subtype IfcWallStandardCase) defines the occuurence of any wall, common information about wall types (or styles) is handled by IfcWallType. The IfcWallType (if present) may establish the common type name, usage (or predefined) type, common material layer set, common set of properties and common shape representations (using IfcRepresentationMap). The IfcWallType is attached using the IfcRelDefinedByType.RelatingType objectified relationship and is accessible by the inverse IsDefinedBy attribute.
Property Set Use Definition:
The property sets relating to the IfcWall are defined by the IfcPropertySet and attached by the IfcRelDefinesByProperties relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to the IfcWall are part of this IFC release:
Quantity Use Definition:
The quantities relating to the IfcWall 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 
NominalLength  Total nominal (or average) length of the wall along the wall path. The exact definition and calculation rules depend on the method of measurement used.  IfcQuantityLength 
NominalWidth  Total nominal (or average) width (or thickness) of the wall perpendicular to the wall path. The exact definition and calculation rules depend on the method of measurement used.  IfcQuantityLength 
NominalHeight  Total nominal (or average) height of the wall along the wall path. The exact definition and calculation rules depend on the method of measurement used.  IfcQuantityLength 
GrossFootprintArea  Area of the wall as viewed by a ground floor view, not taking any wall modifications (like recesses) into account. It is also referred to as the foot print of the wall. The exact definition and calculation rules depend on the method of measurement used.  IfcQuantityArea 
NetFootprintArea  Area of the wall as viewed by a ground floor view, taking all wall modifications (like recesses) into account. It is also referred to as the foot print of the wall. The exact definition and calculation rules depend on the method of measurement used.  IfcQuantityArea 
GrossSideAreaLeft  Area of the wall as viewed by an elevation view of the left side (when viewed along the wall path orientation). It does not take into account any wall modifications (such as openings). The exact definition and calculation rules depend on the method of measurement used.  IfcQuantityArea 
NetSideAreaLeft  Area of the wall as viewed by an elevation view of the left side (when viewed along the wall path orientation). It does take into account all wall modifications (such as openings). The exact definition and calculation rules depend on the method of measurement used.  IfcQuantityArea 
GrossSideAreaRight  Area of the wall as viewed by an elevation view of the right side (when viewed along the wall path orientation). It does not take into account any wall modifications (such as openings). The exact definition and calculation rules depend on the method of measurement used.  IfcQuantityArea 
NetSideAreaRight  Area of the wall as viewed by an elevation view of the right side (when viewed along the wall path orientation). It does take into account all wall modifications (such as openings). The exact definition and calculation rules depend on the method of measurement used.  IfcQuantityArea 
GrossVolume  Volume of the wall, without taking into account the openings and the connection geometry. The exact definition and calculation rules depend on the method of measurement used.  IfcQuantityVolume 
NetVolume  Volume of the wall, after subtracting the openings and after considering the connection geometry. The exact definition and calculation rules depend on the method of measurement used.  IfcQuantityVolume 
Containment Use Definition
The IfcWall (and the subtype IfcWallStandardCase) as any subtype of IfcBuildingElement, may participate in two different containment relationships. The first (and in most implementation scenarios mandatory) relationship is the hierachical spatial containment, the second (optional) relationship is the aggregation within an element assembly.
The IfcWall may also be
an aggregate i.e. being composed by other
elements and acting as an assembly using the objectified relationship IfcRelAggregates,
refering to it by its inverse attribute SELF\IfcObjectDefinition.IsDecomposedBy.
Components of a wall are described by instances of IfcBuildingElementPart
that are aggregated to form a complex wall.
In this case, the contained IfcBuildingElementPart's
should not be additionally contained in the project
spatial hierarchy, i.e. the inverse attribute SELF\IfcElement.ContainedInStructure
of IfcBuildingElementPart should be NIL.
The geometric representation of IfcWall is given by the IfcProductDefinitionShape, allowing multiple geometric representation. Included are:
Local Placement
The local placement for IfcWall 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.
Geometric Representations
Currently, the use of 'SweptSolid', 'Clipping', and 'Brep' representations is supported. In addition the general representation types 'SurfaceModel' and 'BoundingBox' are allowed. The geometry use definition for 'BoundingBox', 'SurfaceModel' and 'Brep' is explained at IfcBuildingElement. A more restricted geometry definition is given at the level of the subtype IfcWallStandardCase.
SweptSolid representation
The standard geometric representation (for body) of IfcWall is defined using the 'SweptSolid' representation. It is based on the vertical extrusion of a polygonal footprint of the wall body. The IfcShapeRepresentation shall have the following values:
The following additional constraints apply to the swept solid representation:
Connection Geometry
The connection between two walls is represented by the IfcRelConnectsPathElements. The use of the parameter of that relationship object is defined at the level of the subtypes of IfcWall and at the IfcRelConnectsPathElements.
EXPRESS specification:

WR1  :  There should be only a maximum of one material information of a wall. 
