The wall represents a vertical construction that may bound or subdivide 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. 

There are two main representations for all occurrences:

• IfcWall with IfcMaterialLayerSetUsage is used for all occurrences of walls, that have a non-changing thickness along the wall path and where the thickness parameter can be fully described by a material layer set. These walls are always represented geometrically by an 'Axis' and a 'SweptSolid' shape representation (or by a 'Clipping' geometry based on 'SweptSolid'), if a 3D geometric representation is assigned
• IfcWall without IfcMaterialLayerSetUsage is used for all other occurrences of wall, particularly for walls with changing thickness along the wall path (e.g. polygonal walls), or walls with a non-rectangular cross sections (e.g. L-shaped retaining walls), and walls having an extrusion axis that is unequal to the global Z axis of the project (i.e. non-vertical walls), or walls having only 'Brep', or 'SurfaceModel' geometry, or if a more parametric representation is not intended

The wall axis is represented by a two-dimensional open curve within a particular shape representation. The 'Axis' shape representation is only used to locate the material layer set along the axis, if the IfcMaterialLayerSetUsage is applied to the IfcWall. In this case, the wall axis is used to apply the material layer set usage parameter to the wall geometry. 

The image below illustrates an axis representation for a straight wall. In case of a straight wall, the set of items includes a single geometric representation item of type IfcPolyline or IfcTrimmedCurve with the BasisCurve being an IfcLine. The IfcPolyline or IfcTrimmedCurve is parallel (here in a special case co-linear) to the x-axis of the object coordinate system. The direction is identical to the direction of the x-axis. 

The image below illustrates an axis representation for a curved wall. In case of a curved wall, the set of items includes a single geometric representation item of type IfcTrimmedCurve. The curve has a BasisCurve of type IfcCircle. The tangent of the IfcTrimmedCurve is parallel at start to the x-axis of the object coordinate system. The direction is identical to the direction of the x-axis. 

The following additional constraints apply to the 'SweptSolid' representation, when an IfcMaterialLayerSetUsage is assigned to the IfcSlab:

• Solid: IfcExtrudedAreaSolid is required
• Profile: IfcArbitraryClosedProfileDef and IfcRectangleProfileDef is supported
• Extrusion: All extrusion directions is supported
• Boolean result: The IfcBooleanClippingResult is supported, allowing for Boolean differences between the swept solid (here IfcExtrudedAreaSolid) and one or several IfcHalfSpaceSolid (or subtypes)

The image below illustrates a clipping for a straight wall using an IfcPolygonalBoundedHalfSpace as SecondOperand in the IfcBooleanClippingResult. 

The image below illustrates a clipping for a curved wall using an IfcHalfSpaceSolid as SecondOperand in the IfcBooleanClippingResult. 

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

• Solid: IfcExtrudedAreaSolid is required
• Profile: IfcArbitraryClosedProfileDef and IfcRectangleProfileDef is supported
• Extrusion: All extrusion directions is supported

The image below illustrates a body representation for a straight wall. In case of a straight wall, the two sides of the profile are parallel to the wall axis, that is, the wall has a single unchanged thickness. 

The image below illustrates a body representation for a curved wall. In case of a curved wall, the two sides of the profile are parallel (with defined offset) to the wall axis, that is, the wall has a single unchanged thickness. 

A wall can be decomposed into parts such as framing and panels on each side. For efficiency, each part can reuse geometry using the mapped geometry concept. This concept can be applied to the following resources:

• IfcMember - Studs, posts and similar elements
• IfcMechanicalFastener - Fasteners that can be used to connect elements together with IfcRelConnectsWithRealizingElements
• IfcElementAssembly - Frame containing studs, tracks, and possibly insulation
• IfcBuildingElementPart - Panels on each side such as gypsum (drywall) or cement board (tile backing) with fasteners

The image below openings within the composite wall are directly assigned to IfcWall using IfcRelVoidsElement pointing to IfcOpeningElement and apply to all aggregated parts. If individual parts have cutting and other voiding features, then the decomposed parts have a separate voiding relationship IfcRelVoidsElement pointing to IfcVoidingFeature. 

The image below illustrates assignment of IfcMaterialLayerSetUsage and IfcMaterialLayerSet to the IfcWallType and the IfcWall occurrence. 

This concept can be applied to the following resources:

• LoadBearing
• Insulation

This concept can be applied to the following resources:

• IfcWallType

This concept can be applied to the following resources:

• IfcWall - Walls with equal or lower priority are connected at RelatedElement

This concept can be applied to the following resources:

• IfcStructuralSurfaceMember - an idealized structural member corresponding to the wall
• IfcTask - A task for operating on the wall

This concept can be applied to the following resources:

• Pset_ConcreteElementGeneral
• Pset_PrecastConcreteElementFabrication
• Pset_PrecastConcreteElementGeneral
• Pset_RoadGuardElement (only applies to PARAPET)
• Pset_ReinforcementBarPitchOfWall
• Pset_WallCommon

This concept can be applied to the following resources:

• Qto_WallBaseQuantities

The IfcWall, as any subtype of IfcBuildingElement, can participate alternatively in one of the two different containment relationships:

• the Spatial Containment (defined here)
• the Element Composition

The 'Surface' can be used to define a surface model of the building (e.g. for analytical purposes, or for reduced Level of Detail representation).