8.10.3.7 IfcMaterialLayerSet

RV ⓘ

AbV ⓘ

8.10.3.7.1 Semantic definition

The IfcMaterialLayerSet is a designation by which materials of an element constructed of a number of material layers is known and through which the relative positioning of individual layers can be expressed.

The Material Layer Set Base (MlsBase) describes the imaginary axis along which the material layers are positioned.

In case of assigning the IfcMaterialLayerSet directly to an element or element type, the individual layers are stacked according to their position within the list of MaterialLayers without providing information on how to spatially relate the material layer information to the shape representation of the element or element type.
In case of assigning the IfcMaterialLayerSet through an IfcMaterialLayerSetUsage to an element, the MlsBase is positioned along the reference axis or reference plane of the element. An offset from the reference axis or plane to MlsBase is supported by IfcMaterialLayerSetUsage which combines layers and an offset. Offsets from element edges are supported by the subtype IfcMaterialLayerWithOffsets. The positive LayerSetDirection (MlsDirection) describes the direction by which the individual material layers are stacked. The IfcMaterialLayer's are stacked with no gap. Gaps within a material layer set are expressed as layers by themselves.

Attribute use definition

As shown in Figure 8.10.3.7.A, each IfcMaterialLayerSet implicitly defines a material layer set base line (MlsBase), to which the start of the first IfcMaterialLayer is aligned. The total thickness of a layer set is calculated from the individual layer thicknesses, the first layer starting from the MlsBase and following layers being placed on top of the previous (no gaps or overlaps).

8.10.3.7.2 Entity inheritance

- IfcMaterialDefinition

8.10.3.7.3 Attributes

#	Attribute	Type	Description
IfcMaterialDefinition (3)
	AssociatedTo	SET [0:?] OF IfcRelAssociatesMaterial FOR RelatingMaterial	Use of the IfcMaterialDefinition subtypes within the material association of an element occurrence or element type. The association is established by the IfcRelAssociatesMaterial relationship. IFC4-CHANGE The inverse attribute has been added.
	HasExternalReferences	SET [0:?] OF IfcExternalReferenceRelationship FOR RelatedResourceObjects	Reference to external references, e.g. library, classification, or document information, that are associated to the material. IFC4-CHANGE The inverse attribute has been added.
	HasProperties	SET [0:?] OF IfcMaterialProperties FOR Material	Material properties assigned to instances of subtypes of IfcMaterialDefinition. IFC4-CHANGE The inverse attribute has been added.
Click to show 3 hidden inherited attributes
IfcMaterialLayerSet (4)
1	MaterialLayers	LIST [1:?] OF IfcMaterialLayer	Identification of the IfcMaterialLayer’s from which the IfcMaterialLayerSet is composed.
2	LayerSetName	OPTIONAL IfcLabel	The name by which the IfcMaterialLayerSet is known.
3	Description	OPTIONAL IfcText	Definition of the IfcMaterialLayerSet in descriptive terms. IFC4-CHANGE The attribute has been added at the end of attribute list.
*	TotalThickness	IfcLengthMeasure	This attribute is formally derived. `IfcMlsTotalThickness(SELF)` Total thickness of the material layer set is derived from the function IfcMlsTotalThickness.

Table 8.10.3.7.F

8.10.3.7.4 Examples

Figure 8.10.3.7.B

Wall Extrusion
Figure 8.10.3.7.C

Slab Extrusion
Figure 8.10.3.7.D

Slab Openings
Figure 8.10.3.7.E

Construction Scheduling Task

8.10.3.7.5 Formal representation

 ENTITY IfcMaterialLayerSet
 SUBTYPE OF (IfcMaterialDefinition);
	MaterialLayers : LIST [1:?] OF IfcMaterialLayer;
	LayerSetName : OPTIONAL IfcLabel;
	Description : OPTIONAL IfcText;
 DERIVE
	 TotalThickness : IfcLengthMeasure := IfcMlsTotalThickness(SELF);
END_ENTITY;