8.10.3.18 IfcMaterialUsageDefinition

ABSTRACT This definition may not be instantiated

8.10.3.18.1 Semantic definition

IfcMaterialUsageDefinition is a general supertype for all material related information items in IFC that have occurrence specific assignment parameters to assign a set of materials with shape parameters to a reference geometry item of that component.

There are two ways of assigning a set of materials with shape parameters:

a layer set to a reference curve - assigning a material layer set with material layers having a sequence and thickness parameter to a reference curve of an element - represented by the 'Axis' shape representation of that element
a profile set to a cardinal point - assigning a material profile set with assigned profile geometry and insertion points to a reference curve by an offset, called "cardinal point" - the reference curve is represented by the 'Axis' shape representation of that element

Each instantiable subtype of IfcMaterialUsageDefinition has to be assigned to a subtype of IfcElement by using the objectified relationship IfcRelAssociatesMaterial; it is only valid in conjunction with an element occurrence.

Informal Propositions

It is illegal to assign a subtype of IfcMaterialUsageDefinition to a subtype of IfcElementType, it shall only be assigned to an element occurrence.

8.10.3.18.2 Entity inheritance

8.10.3.18.3 Attributes

#	Attribute	Type	Description
IfcMaterialUsageDefinition (1)
	AssociatedTo	SET [1:?] OF IfcRelAssociatesMaterial FOR RelatingMaterial	Use of the IfcMaterialUsageDefinition subtypes within the material association of an element occurrence. The association is established by the IfcRelAssociatesMaterial relationship.

Table 8.10.3.18.A

8.10.3.18.4 Formal representation

 ENTITY IfcMaterialUsageDefinition
 ABSTRACT SUPERTYPE OF (ONEOF
	(IfcMaterialLayerSetUsage
	,IfcMaterialProfileSetUsage));
 INVERSE
	AssociatedTo : SET [1:?] OF IfcRelAssociatesMaterial FOR RelatingMaterial;
END_ENTITY;