#### 5.4.3.17 IfcRelAssociatesMaterial

| Association de matériau
| Ordnet Material zu - Relation

IfcRelAssociatesMaterial is an objectified relationship between a material definition and elements or element types to which this material definition applies.

The material definition can be:

- assigned to an element occurrence as a specific usage of a layer set or profile set
- assigned to an element occurrence or element type as a layer set, profile set, constituent set or a single material

Materials can be arranged by layers and applied to layered elements. Typical elements are walls and slabs.

- An IfcMaterialLayerSet, for layered elements with an indication of the layering direction and individual layer thicknesses
- An IfcMaterialLayerSetUsage, i.e. a material layer set with positioning information along the reference axis or surface of the element.

  > NOTE As a material layer set usage is an occurrence based information, that applies to each individual element, it cannot be assigned to an element type.

Material can be applied to profiles. Typical elements using profile material are beam, column, member

- An IfcMaterialProfileSet, i.e. a set of material assigned to a set of profiles, with a single material assigned to a single profile as the default.
- An IfcMaterialProfileSetUsage, i.e. a material profile set with positioning information relative to the element axis, also refered to as cardinal point.

  > NOTE As a material profile set usage is an occurrence based information, that applies to each individual element, it cannot be assigned to an element type.

Materials can be arranged by identified parts of a component based element. Typical elements are dorrs/windows (with components such as lining, framing and glazing), or distribution elements.

- An IfcMaterialConstituentSet, for component based elements with an indication of the component by keyword to which the material consituent applies.

  > NOTE See the material use definitions at each applicable subtype of IfcElement or IfcElementType for a provision of these keywords.

As a fallback, or in cases where only a single material information is needed, material information can be directly associated

- A single IfcMaterial for any element where the material use definition does not prohibits its direct association
- An IfcMaterialList, e.g. for composite elements, without an information, how the different materials are arranged.

  > DEPRECATED The use of IfcMaterialList is deprecated in IFC4 onwards. Use IfcMaterialConstituentSet instead.

The IfcRelAssociatesMaterial relationship is a special type of the IfcRelAssociates relationship. It can be applied to subtypes of IfcElement and subtypes of IfcElementType.

- The IfcElement has an inverse relation to its material definition by the HasAssociations attribute, inherited from IfcObject.
- The IfcElementType has an inverse relation to its material definition by the HasAssociations attribute, inherited from IfcPropertyDefinition.

If both, the element occurrence (by an instance of IfcElement) and the element type (by an instance of IfcElementType, connected through IfcRelDefinesByType) have an associated material, then the material associated to the element occurrence overrides the material associated to the element type.

> HISTORY New entity in IFC2x.

Informal Propositions:

1. An IfcMaterialLayerSetUsage shall not be associated with a subtype of IfcElementType, it should only be associated with individual occurrences
2. An IfcMaterialProfileSetUsage shall not be associated with a subtype of IfcElementType, it should only be associated with individual occurrences

XSD Specification:

<xs:element name="IfcRelAssociatesMaterial" type="ifc:IfcRelAssociatesMaterial" substitutionGroup="ifc:IfcRelAssociates" nillable="true"/>
<xs:complexType name="IfcRelAssociatesMaterial">
<xs:complexContent>
<xs:extension base="ifc:IfcRelAssociates">
<xs:sequence>
<xs:element name="RelatingMaterial">
<xs:complexType>
<xs:group ref="ifc:IfcMaterialSelect"/>
</xs:complexType>
</xs:element>
</xs:sequence>
</xs:extension>
</xs:complexContent>
</xs:complexType>

EXPRESS Specification:

ENTITY IfcRelAssociatesMaterial

| SUBTYPE OF (IfcRelAssociates);

RelatingMaterial | : | IfcMaterialSelect;

| WHERE

NoVoidElement | : | SIZEOF(QUERY(temp <* SELF\IfcRelAssociates.RelatedObjects | ('IFCPRODUCTEXTENSION.IFCFEATUREELEMENTSUBTRACTION' IN TYPEOF(temp)) OR ('IFCPRODUCTEXTENSION.IFCVIRTUALELEMENT' IN TYPEOF(temp)) )) = 0;
AllowedElements | : | SIZEOF(QUERY(temp <* SELF\IfcRelAssociates.RelatedObjects | ( SIZEOF(TYPEOF(temp) * [ 'IFCPRODUCTEXTENSION.IFCELEMENT', 'IFCPRODUCTEXTENSION.IFCELEMENTTYPE', 'IFCSHAREDBLDGELEMENTS.IFCWINDOWSTYLE', 'IFCSHAREDBLDGELEMENTS.IFCDOORSTYLE', 'IFCSTRUCTURALANALYSISDOMAIN.IFCSTRUCTURALMEMBER', 'IFCPRODUCTEXTENSION.IFCPORT']) = 0) )) = 0;

END_ENTITY;

Attribute Definitions:

RelatingMaterial | : | Material definition assigned to the elements or element types.

Formal Propositions:

NoVoidElement | : | The material information must not be associated to a substraction feature (such as an opening) or to a virtual element.
AllowedElements | : | The material information, using IfcMaterialSelect should be associated to an element occurrence (including structural members) or an element type (including the door and window styles). Also port can have assigned materials, here indicating the fluid flowing from the port.

Inheritance Graph:

ENTITY IfcRelAssociatesMaterial

| ENTITY IfcRoot

GlobalId | : | IfcGloballyUniqueId;
OwnerHistory | : | OPTIONAL IfcOwnerHistory;
Name | : | OPTIONAL IfcLabel;
Description | : | OPTIONAL IfcText;

| ENTITY IfcRelationship

| ENTITY IfcRelAssociates

RelatedObjects | : | SET [1:?] OF IfcDefinitionSelect;

| ENTITY IfcRelAssociatesMaterial

RelatingMaterial | : | IfcMaterialSelect;

END_ENTITY;

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