IFC 4.3.x development

6.3.3.10 IfcMechanicalFastenerType

Change log

IFC4

additions attributes NominalDiameter
additions attributes NominalLength
additions attributes PredefinedType
additions where_rulesCorrectPredefinedType
modificationssupertype Changed from IfcFastenerType to IfcElementComponentType

6.3.3.10.1 Semantic definitions at the entity

The element component type IfcMechanicalFastenerType defines commonly shared information for occurrences of mechanical fasteners. The set of shared information may include:

  • common properties with shared property sets
  • common representations
  • common materials
  • common composition of elements

It is used to define a mechanical fastener type specification indicating the specific product information that is common to all occurrences of that product type. The IfcMechanicalFastenerType may be declared within IfcProject or IfcProjectLibrary using IfcRelDeclares and may be exchanged with or without occurrences of the type. Occurrences of IfcMechanicalFastenerType are represented by instances of IfcMechanicalFastener.

HISTORY  New entity in IFC2x2

IFC4 CHANGE  Supertype changed from IfcFastenerType to IfcElementComponentType. Attributes PredefinedType, NominalDiameter, NominalLength added.

Classification Use Definition

Mechanical fasteners, especially bolts, are often standardized. To refer to a formal fastener designation according to a standard (a product norm), IfcRelAssociatesClassification together with IfcClassificationReference should be used.

  • IfcClassificationReference.Identification contains a machine-readable form of the formal fastener designation from the norm. Example: 'M16X80-10.9-HV' for a high-strength structural bolting assembly for preloading with hexagon bolt and nut. (On the other hand, IfcMechanicalFastenerType.Name contains a displayable name which may not necessarily be the same as the formal designation.)
  • IfcClassificationReference.Name carries the short name of the fastener norm. Example: 'EN 14399-4' as the respective European standard for high-strength hexagon bolts.
  • Optionally, the norm can be further described by IfcClassificationReference.ReferencedSource, including information like publisher and date of issue of the norm.

Furthermore, IfcRelAssociatesLibrary together with IfcLibraryReference may be used to refer to a library which contains fastener definitions.

6.3.3.10.1 Attributes

# Attribute Type Description
IfcRoot
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,

> NOTE  only the last modification in stored - either as addition, deletion or modification.

> IFC4 CHANGE  The attribute has been changed to be OPTIONAL.
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.
IfcObjectDefinition
HasAssignments SET [0:?] OF IfcRelAssigns FOR RelatedObjects Reference to the relationship objects, that assign (by an association relationship) other subtypes of IfcObject to this object instance. Examples are the association to products, processes, controls, resources or groups.
Nests SET [0:1] OF IfcRelNests FOR RelatedObjects References to the decomposition relationship being a nesting. It determines that this object definition is a part within an ordered whole/part decomposition relationship. An object occurrence or type can only be part of a single decomposition (to allow hierarchical strutures only).

> IFC4 CHANGE  The inverse attribute datatype has been added and separated from Decomposes defined at IfcObjectDefinition.
IsNestedBy SET [0:?] OF IfcRelNests FOR RelatingObject References to the decomposition relationship being a nesting. It determines that this object definition is the whole within an ordered whole/part decomposition relationship. An object or object type can be nested by several other objects (occurrences or types).

> IFC4 CHANGE  The inverse attribute datatype has been added and separated from IsDecomposedBy defined at IfcObjectDefinition.
HasContext SET [0:1] OF IfcRelDeclares FOR RelatedDefinitions References to the context providing context information such as project unit or representation context. It should only be asserted for the uppermost non-spatial object.

> IFC4 CHANGE  The inverse attribute datatype has been added.
IsDecomposedBy SET [0:?] OF IfcRelAggregates FOR RelatingObject References to the decomposition relationship being an aggregation. It determines that this object definition is whole within an unordered whole/part decomposition relationship. An object definitions can be aggregated by several other objects (occurrences or parts).

> IFC4 CHANGE  The inverse attribute datatype has been changed from the supertype IfcRelDecomposes to subtype IfcRelAggregates.
Decomposes SET [0:1] OF IfcRelAggregates FOR RelatedObjects References to the decomposition relationship being an aggregation. It determines that this object definition is a part within an unordered whole/part decomposition relationship. An object definitions can only be part of a single decomposition (to allow hierarchical strutures only).

> IFC4 CHANGE  The inverse attribute datatype has been changed from the supertype IfcRelDecomposes to subtype IfcRelAggregates.
HasAssociations SET [0:?] OF IfcRelAssociates FOR RelatedObjects Reference to the relationship objects, that associates external references or other resource definitions to the object.. Examples are the association to library, documentation or classification.
IfcTypeObject
5 ApplicableOccurrenceOPTIONAL IfcIdentifier The attribute optionally defines the data type of the occurrence object, to which the assigned type object can relate. If not present, no instruction is given to which occurrence object the type object is applicable. The following conventions are used:

* The IFC entity name of the applicable occurrence using the IFC naming convention, CamelCase with IFC prefix

* It can be optionally followed by the predefined type after the separator "/" (forward slash), using uppercase

* If one type object is applicable to many occurrence objects, then those occurrence object names should be separate by comma "," forming a comma separated string.

> EXAMPLE Refering to a furniture as applicable occurrence entity would be expressed as 'IfcFurnishingElement', refering to a brace as applicable entity would be expressed as 'IfcMember/BRACE', refering to a wall and wall standard case would be expressed as 'IfcWall, IfcWallStandardCase'.
6 HasPropertySets OPTIONAL SET [1:?] OF IfcPropertySetDefinition Set ~~list~~ of unique property sets, that are associated with the object type and are common to all object occurrences referring to this object type.

> IFC2x3 CHANGE  The attribute aggregate type has been changed from LIST to SET.
Types SET [0:1] OF IfcRelDefinesByType FOR RelatingType Reference to the relationship IfcRelDefinedByType and thus to those occurrence objects, which are defined by this type.
IfcTypeProduct
7 RepresentationMaps OPTIONAL LIST [1:?] OF UNIQUE IfcRepresentationMap List of unique representation maps. Each representation map describes a block definition of the shape of the product style. By providing more than one representation map, a multi-view block definition can be given.
8 Tag OPTIONAL IfcLabel The tag (or label) identifier at the particular type of a product, e.g. the article number (like the EAN). It is the identifier at the specific level.
ReferencedBy SET [0:?] OF IfcRelAssignsToProduct FOR RelatingProductReference to the IfcRelAssignsToProduct relationship, by which other products, processes, controls, resources or actors (as subtypes of IfcObjectDefinition) can be related to this product type.

> IFC4 CHANGE  New inverse relationship.
IfcElementType
9 ElementType OPTIONAL IfcLabel The type denotes a particular type that indicates the object further. The use has to be established at the level of instantiable subtypes. In particular it holds the user defined type, if the enumeration of the attribute 'PredefinedType' is set to USERDEFINED.
IfcElementComponentType
IfcMechanicalFastenerType
10 PredefinedType IfcMechanicalFastenerTypeEnum Subtype of mechanical fastener
11 NominalDiameter OPTIONAL IfcPositiveLengthMeasure The nominal diameter describing the cross-section size of the fastener type.
12 NominalLength OPTIONAL IfcPositiveLengthMeasure The nominal length describing the longitudinal dimensions of the fastener type.

6.3.3.10.2 Entity inheritance

dot_inheritance IfcMechanicalFastenerType IfcMechanicalFastenerType IfcElementComponentType IfcElementComponentType IfcMechanicalFastenerType->IfcElementComponentType IfcElementComponentType_children 8 more... IfcElementComponentType_children->IfcElementComponentType IfcElementType IfcElementType IfcElementComponentType->IfcElementType IfcElementType_children 7 more... IfcElementType_children->IfcElementType IfcTypeProduct IfcTypeProduct IfcElementType->IfcTypeProduct IfcTypeProduct_children 3 more... IfcTypeProduct_children->IfcTypeProduct IfcTypeObject IfcTypeObject IfcTypeProduct->IfcTypeObject IfcTypeProcess IfcTypeProcess IfcTypeProcess->IfcTypeObject IfcObjectDefinition IfcObjectDefinition IfcTypeObject->IfcObjectDefinition IfcTypeResource IfcTypeResource IfcTypeResource->IfcTypeObject IfcContext IfcContext IfcContext->IfcObjectDefinition IfcRoot IfcRoot IfcObjectDefinition->IfcRoot IfcObject IfcObject IfcObject->IfcObjectDefinition IfcPropertyDefinition IfcPropertyDefinition IfcPropertyDefinition->IfcRoot IfcRelationship IfcRelationship IfcRelationship->IfcRoot

6.3.3.10.3 Definitions applying to General Usage

6.3.3.10.3.1 Classification Association

Any object occurrence or object type can have a reference to a specific classification reference, i.e. to a particular facet within a classification system.

6.3.3.10.3.2 Identity

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

6.3.3.10.3.3 Product Type Shape

The RepresentationMaps define the type product shape and multiple geometric representations can be assigned. If a product occurrence is assigned to the type by using the IfcRelDefinesByType relationship, then these occurrences have to reference the representation maps. The reference is created by one or multiple IfcShapeRepresentation's having an IfcMappedItem as Items, that places the IfcRepresentationMap of the type product into the spatial contexts, i.e. by using an Cartesian transformation operator to transform the IfcRepresentationMap into the object coordinate system of the product occurrence.

Figure 136 illustrates an example of referencing a representation map by the shape representation of a product occurrence. Here the Cartesian transformation operator only uses translation, but no rotation, mirroring, or scaling.

representation map

Figure 136 — Product type geometry with single placement

Figure 137 illustrates an example of referencing a representation multiple times map by the shape representation of a product occurrence. Here the Cartesian transformation operator only uses translation, but no rotation, mirroring, or scaling. The different translation values determine the pattern of the multiple placement.

representation map

Figure 137 — Product type geometry with multiple placement

6.3.3.10.3.4 Revision Control

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

6.3.3.10.4 Formal representations

ENTITY IfcMechanicalFastenerType
 SUBTYPE OF (IfcElementComponentType);
	PredefinedType : IfcMechanicalFastenerTypeEnum;
	NominalDiameter : OPTIONAL IfcPositiveLengthMeasure;
	NominalLength : OPTIONAL IfcPositiveLengthMeasure;
 WHERE
	CorrectPredefinedType : (PredefinedType <> IfcMechanicalFastenerTypeEnum.USERDEFINED) OR
((PredefinedType = IfcMechanicalFastenerTypeEnum.USERDEFINED) AND EXISTS(SELF\IfcElementType.ElementType));
END_ENTITY;