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. |
|
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;