IFC (IFC4X3_ADD1) IfcRelAssociatesMaterial 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 Entity inheritance Attributes

# Attribute Type Description
IfcRoot (4)
1 GlobalId IfcGloballyUniqueId

Assignment of a globally unique identifier within the entire software world.

2 OwnerHistory OPTIONAL IfcOwnerHistory

Assignment of the information about the current ownership of that object, including owning actor, application, local identification and information captured about the recent changes of the object,

3 Name OPTIONAL IfcLabel

Optional name for use by the participating software systems or users. For some subtypes of IfcRoot the insertion of the Name attribute may be required. This would be enforced by a where rule.

4 Description OPTIONAL IfcText

Optional description, provided for exchanging informative comments.

IfcRelAssociates (1)
5 RelatedObjects SET [1:?] OF IfcDefinitionSelect

Set of object or property definitions to which the external references or information is associated. It includes object and type objects, property set templates, property templates and property sets and contexts.

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IfcRelAssociatesMaterial (1)
6 RelatingMaterial IfcMaterialSelect

Material definition assigned to the elements or element types.

Table Formal propositions

Name Description

The material information, using IfcMaterialSelect should be associated to an element occurrence (including structural members) or an element type. Also port can have assigned materials, here indicating the fluid flowing from the port.

SIZEOF(QUERY(temp <* SELF\IfcRelAssociates.RelatedObjects | (
  SIZEOF(TYPEOF(temp) * [   
    'IFC4X3_ADD1.IFCPORT']) = 0) 
)) = 0

The material information must not be associated to a substraction feature (such as an opening) or to a virtual element.

SIZEOF(QUERY(temp <* SELF\IfcRelAssociates.RelatedObjects | 
)) = 0
Table Concept usage

Concept Usage Description
IfcRoot (2)
Revision Control General

Ownership, history, and merge state is captured using IfcOwnerHistory.

Software Identity General

IfcRoot assigns the globally unique ID. In addition it may provide for a name and a description about the concept.

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Table Formal representation

ENTITY IfcRelAssociatesMaterial
 SUBTYPE OF (IfcRelAssociates);
	RelatingMaterial : IfcMaterialSelect;
	AllowedElements : SIZEOF(QUERY(temp <* SELF\IfcRelAssociates.RelatedObjects | (
  SIZEOF(TYPEOF(temp) * [   
    'IFC4X3_ADD1.IFCPORT']) = 0) 
)) = 0;
	NoVoidElement : SIZEOF(QUERY(temp <* SELF\IfcRelAssociates.RelatedObjects | 
)) = 0;
END_ENTITY; References Changelog IFC4

  • where rule, AllowedElements
  • where rule, NoVoidElement
  • where rule, WR21
  • where rule, WR22 IFC4.3_ADD1

  • where rule AllowedElements definition, Changed from "sizeof(query(temp <* self\IfcRelAssociates.RelatedObjects | (sizeof(typeof(temp)*[ifcelement,ifcelementtype,ifcwindowstyle,ifcdoorstyle,ifcstructuralmember,ifcport]) = 0))) = 0" to "sizeof(query(temp <* self\IfcRelAssociates.RelatedObjects | (sizeof(typeof(temp)*[ifcelement,ifcelementtype,ifcstructuralmember,ifcport]) = 0))) = 0"