IfcRelProjectsElement

BACnet MVD

#### IfcRelProjectsElement

Natural language names

| Hinzufügen / Addition von Teil zu Element - Relation
| Rel Projects Element

Change log

Item | SPF | XML | Change | Description
--- | --- | --- | --- | ---
IFC2x3 to IFC4
IfcRelProjectsElement |  |  |  |
OwnerHistory |  |  | MODIFIED | Instantiation changed to OPTIONAL.
IFC4 Addendum 2
IfcRelProjectsElement |  |  |  |
RelatingElement |  | X | MODIFIED | Xsdformat changed from Attribute to Hidden.

##### Semantic definitions at the entity

Entity definition

The IfcRelProjectsElement is an objectified relationship between an element and one projection element that creates a modifier to the shape of the element. The relationship is defined to be a 1:1 relationship, if an element has more than one projection, several relationship objects have to be used, each pointing to a different projection element. The IfcRelProjectsElement establishes an aggregation relationship between the main element and a sub ordinary addition feature.

> NOTE In contrary the IfcRelAggregates relationship established an aggregation of equal parts to a whole.

The IfcRelProjectsElement implies a Boolean operation of addition for the geometric bodies of the element and the feature element. As with all decomposition relationships it determines:

- existence dependency - the RelatedFeatureElement cannot exist without the RelatingElement
- hierarchical and non-cyclical relationship - the IfcRelProjectsElement can only alter a single IfcElement
- no spatial containment - the IfcFeatureElementAddition as related element never participates in the hiearchical spatial containment relationship IfcRelContainedInSpatialStructure

> HISTORY New entity in IFC2x2.

> IFC4 CHANGE Supertype changed to IfcRelDecomposes.

Attribute definitions

# | Attribute | Type | Cardinality | Description | B
--- | --- | --- | --- | --- | ---
5 | RelatingElement | IfcElement |  | Element at which a projection is created by the associated IfcProjectionElement. | X | X
6 | RelatedFeatureElement | IfcFeatureElementAddition |  | Reference to the IfcFeatureElementAddition that defines an addition to the volume of the element, by using a Boolean addition operation. An example is a projection at the associated element. | X | X

##### Inherited definitions from supertypes

Entity inheritance
Attribute inheritance

# | Attribute | Type | Cardinality | Description | B
--- | --- | --- | --- | --- | ---
IfcRoot
1 | GlobalId | IfcGloballyUniqueId |  | Assignment of a globally unique identifier within the entire software world. | X | X

2

OwnerHistory

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.

X

X

3 | Name | 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. | X | X
4 | Description | IfcText | ? | Optional description, provided for exchanging informative comments. |  | X
IfcRelationship
IfcRelDecomposes
IfcRelProjectsElement
5 | RelatingElement | IfcElement |  | Element at which a projection is created by the associated IfcProjectionElement. | X | X
6 | RelatedFeatureElement | IfcFeatureElementAddition |  | Reference to the IfcFeatureElementAddition that defines an addition to the volume of the element, by using a Boolean addition operation. An example is a projection at the associated element. | X | X

##### Definitions applying to Design Transfer View

Concept inheritance

# | Concept | Template | Model View
--- | --- | --- | ---
IfcRoot
| Revision Control | Revision Control | Design Transfer View

##### Definitions applying to BACnet View

Concept inheritance

# | Concept | Template | Model View
--- | --- | --- | ---
IfcRoot
| Revision Control | Revision Control | Design Transfer View

##### Formal representations

XML Specification
`<xs:element name="IfcRelProjectsElement" type="ifc:IfcRelProjectsElement" substitutionGroup="ifc:IfcRelDecomposes" nillable="true"/>
<xs:complexType name="IfcRelProjectsElement">
<xs:complexContent>
<xs:extension base="ifc:IfcRelDecomposes">
<xs:sequence>
<xs:element name="RelatedFeatureElement" type="ifc:IfcFeatureElementAddition" nillable="true"/>
</xs:sequence>
</xs:extension>
</xs:complexContent>
</xs:complexType>
`
EXPRESS Specification
`ENTITY IfcRelProjectsElement
SUBTYPE OF (IfcRelDecomposes);
RelatingElement : IfcElement;
RelatedFeatureElement : IfcFeatureElementAddition;
END_ENTITY;

EXPRESS-G diagram

`

References: IfcElement IfcFeatureElementAddition

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