A surface feature is a modification at (onto, or into) of the surface of an element. Parts of the surface of the entire surface can be affected. The volume and mass of the element can be increased, remain unchanged, or be decreased by the surface feature, depending on manufacturing technology. However, any increase or decrease of volume is small compared to the total volume of the element. 

The part–whole relationship is established by an aggregation relationship object, expressing the decomposition of an element type into one or more additive elements (element parts) and zero or more feature elements. 

Surface features have no spatial containment relationship to the spatial structure since they are dependent on element types without spatial containment relationships or on an element occurrence with own spatial containment relationship.

• The SELFIfcElement.ContainedInStructure relationship should be NIL.

The geometric representation of IfcSurfaceFeatureElement is specified by the IfcProductDefinitionShape, allowing multiple geometric representation. 

The local placement for IfcSurfaceFeatureElement 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.

• In case of features which are part of an element type, absolute placement into the type object's implied coordinate system is used.
• In case of features which are voiding an element occurrence, the PlacementRelTo relationship of IfcLocalPlacement points to the local placement of the respective element.

Different shape representations can be used, depending on the nature of the feature and information requirements:

• Symbolic representation, such as the two-dimensional bounding box of a tag.
• A geometric set representing the geometric items of a mark.
• Surface representations of treated parts of the element surface by means of IfcShellBasedSurfaceModel. The faces within the surface model can be included into a B-Rep model within a representation map of the parent element type.

Higher-level parameters (geometric and non-geometric) can be provided by property sets based on local agreements. 

The local placement for IfcSurfaceFeatureElement 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.

• In case of features which are part of an element type, absolute placement into the type object's implied coordinate system is used.
• In case of features which are voiding an element occurrence, the PlacementRelTo relationship of IfcLocalPlacement points to the local placement of the respective element.

This concept can be applied to the following resources:

• Pset_RoadMarkingCommon (only applies to HATCHMARKING)
• Pset_RoadMarkingCommon (only applies to LINEMARKING)
• Pset_RoadMarkingCommon (only applies to PAVEMENTSURFACEMARKING)
• Pset_RoadMarkingCommon (only applies to SYMBOLMARKING)
• Pset_MarkingLinesCommon (only applies to LINEMARKING)
• Pset_RoadSymbolsCommon (only applies to SYMBOLMARKING)

This concept can be applied to the following resources:

• Qto_SurfaceFeatureBaseQuantities