# 5.4.3.46 IfcRelAssociatesMaterial

## 5.4.3.46.1 Semantic definition

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.

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 referred to as cardinal point.

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 constituent applies.

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.

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.

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

## 5.4.3.46.6 Formal representation

ENTITY IfcRelAssociatesMaterial
SUBTYPE OF (IfcRelAssociates);
RelatingMaterial : IfcMaterialSelect;
WHERE
AllowedElements : SIZEOF(QUERY(temp <* SELF\IfcRelAssociates.RelatedObjects | (
SIZEOF(TYPEOF(temp) * [
)) = 0;
NoVoidElement : SIZEOF(QUERY(temp <* SELF\IfcRelAssociates.RelatedObjects |
)) = 0;
END_ENTITY;

## 5.4.3.46.7 References

### 5.4.3.46.8 Changelog

#### 5.4.3.46.8.1 IFC4

• where rule, AllowedElements
• where rule, NoVoidElement
• where rule, WR21
• where rule, WR22