 | Vorsprung / Auskragung |
 | Projection Element |
| Item | SPF | XML | Change | Description | IFC2x3 to IFC4 4.0.0.0 |
|---|---|---|---|---|
| IfcProjectionElement | ||||
| OwnerHistory | MODIFIED | Instantiation changed to OPTIONAL. | ||
| PredefinedType | ADDED | IFC4 Addendum 1 4.0.1.0 | ||
| IfcProjectionElement | ||||
| HasCoverings | ADDED | IFC4x2 Candidate 4.2.0.0 | ||
| IfcProjectionElement | ||||
| PositionedRelativeTo | ADDED | IFC4x3_RC3 to IFC4x3_RC4 | ||
| IfcProjectionElement | ||||
| HasSurfaceFeatures | ADDED |
The projection element is a specialization of the general feature element to represent projections applied to building elements. It represents a solid attached to any element that has physical manifestation.
EXAMPLE A wall projection such as a pilaster strip is handled by IfcProjectionElement
NOTE View definitions or implementer agreements may restrict the types of elements to which IfcProjectionElement can be applied.
An IfcProjectionElement has to be linked to a element (all subtypes of IfcElement) by using the IfcRelProjectsElement relationship. Its existence depends on the existence of the master element. The relationship implies a Boolean union operation between the volume of the projection element and the volume of the element.
The IfcProjectionElement shall not participate in the containment relationship, i.e. it is not linked directly to the spatial structure of the project. It has a mandatory ProjectsElements inverse relationship pointing to the IfcElement that is contained in the spatial structure.
HISTORY New entity in IFC2x2.
IFC4 CHANGE The attribute PredefinedType has been added at the end of attribute list.
| # | Attribute | Type | Cardinality | Description | G |
|---|---|---|---|---|---|
| 9 | PredefinedType | IfcProjectionElementTypeEnum | ? |
Predefined generic type for a projection element that is specified in an enumeration. There may be a property set given specificly for the predefined types.
IFC4 CHANGE The attribute has been added at the end of the entity definition. | X |
| Rule | Description |
|---|---|
| CorrectPredefinedType | Either PredefinedType is unset or the inherited attribute ObjectType shall be provided, if the PredefinedType is set to USERDEFINED or PredefinedType. |
| # | Attribute | Type | Cardinality | Description | G |
|---|---|---|---|---|---|
| IfcRoot | |||||
| 1 | GlobalId | IfcGloballyUniqueId | Assignment of a globally unique identifier within the entire software world. | 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 |
| 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 |
| 4 | Description | IfcText | ? | Optional description, provided for exchanging informative comments. | X |
| IfcObjectDefinition | |||||
| HasAssignments | IfcRelAssigns @RelatedObjects | S[0:?] | 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. | X | |
| Nests | IfcRelNests @RelatedObjects | S[0:1] | 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. | X | |
| IsNestedBy | IfcRelNests @RelatingObject | S[0:?] | 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. | X | |
| HasContext | IfcRelDeclares @RelatedDefinitions | S[0:1] | 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. | X | |
| IsDecomposedBy | IfcRelAggregates @RelatingObject | S[0:?] | 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. | X | |
| Decomposes | IfcRelAggregates @RelatedObjects | S[0:1] | 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. | X | |
| HasAssociations | IfcRelAssociates @RelatedObjects | S[0:?] | 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. | X | |
| IfcObject | |||||
| 5 | ObjectType | 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. | X |
| IsDeclaredBy | IfcRelDefinesByObject @RelatedObjects | S[0:1] | Link to the relationship object pointing to the declaring object that provides the object definitions for this object occurrence. The declaring object has to be part of an object type decomposition. The associated IfcObject, or its subtypes, contains the specific information (as part of a type, or style, definition), that is common to all reflected instances of the declaring IfcObject, or its subtypes.
IFC4 CHANGE New inverse relationship, change made with upward compatibility for file based exchange. | X | |
| Declares | IfcRelDefinesByObject @RelatingObject | S[0:?] | Link to the relationship object pointing to the reflected object(s) that receives the object definitions. The reflected object has to be part of an object occurrence decomposition. The associated IfcObject, or its subtypes, provides the specific information (as part of a type, or style, definition), that is common to all reflected instances of the declaring IfcObject, or its subtypes.
IFC4 CHANGE New inverse relationship, change made with upward compatibility for file based exchange. | X | |
| IsTypedBy | IfcRelDefinesByType @RelatedObjects | S[0:1] | Set of relationships to the object type that provides the type definitions for this object occurrence. The then associated IfcTypeObject, or its subtypes, contains the specific information (or type, or style), that is common to all instances of IfcObject, or its subtypes, referring to the same type.
IFC4 CHANGE New inverse relationship, the link to IfcRelDefinesByType had previously be included in the inverse relationship IfcRelDefines. Change made with upward compatibility for file based exchange. | X | |
| IsDefinedBy | IfcRelDefinesByProperties @RelatedObjects | S[0:?] | Set of relationships to property set definitions attached to this object. Those statically or dynamically defined properties contain alphanumeric information content that further defines the object.
IFC4 CHANGE The data type has been changed from IfcRelDefines to IfcRelDefinesByProperties with upward compatibility for file based exchange. | X | |
| IfcProduct | |||||
| 6 | ObjectPlacement | IfcObjectPlacement | ? | Placement of the product in space, the placement can either be absolute (relative to the world coordinate system), relative (relative to the object placement of another product), or constraint (e.g. relative to grid axes). It is determined by the various subtypes of IfcObjectPlacement, which includes the axis placement information to determine the transformation for the object coordinate system. | X |
| 7 | Representation | IfcProductRepresentation | ? | Reference to the representations of the product, being either a representation (IfcProductRepresentation) or as a special case a shape representations (IfcProductDefinitionShape). The product definition shape provides for multiple geometric representations of the shape property of the object within the same object coordinate system, defined by the object placement. | X |
| ReferencedBy | IfcRelAssignsToProduct @RelatingProduct | S[0:?] | Reference to the IfcRelAssignsToProduct relationship, by which other products, processes, controls, resources or actors (as subtypes of IfcObjectDefinition) can be related to this product. | X | |
| PositionedRelativeTo | IfcRelPositions @RelatedProducts | S[0:?] | X | ||
| ReferencedInStructures | IfcRelReferencedInSpatialStructure @RelatedElements | S[0:?] | X | ||
| IfcElement | |||||
| 8 | Tag | IfcIdentifier | ? | The tag (or label) identifier at the particular instance of a product, e.g. the serial number, or the position number. It is the identifier at the occurrence level. | X |
| FillsVoids | IfcRelFillsElement @RelatedBuildingElement | S[0:1] | Reference to the IfcRelFillsElement Relationship that puts the element as a filling into the opening created within another element. | X | |
| ConnectedTo | IfcRelConnectsElements @RelatingElement | S[0:?] | Reference to the element connection relationship. The relationship then refers to the other element to which this element is connected to. | X | |
| IsInterferedByElements | IfcRelInterferesElements @RelatedElement | S[0:?] | Reference to the interference relationship to indicate the element that is interfered. The relationship, if provided, indicates that this element has an interference with one or many other elements.
NOTE There is no indication of precedence between IsInterferedByElements and InterferesElements. IFC4 CHANGE New inverse relationship. | X | |
| InterferesElements | IfcRelInterferesElements @RelatingElement | S[0:?] | Reference to the interference relationship to indicate the element that interferes. The relationship, if provided, indicates that this element has an interference with one or many other elements.
NOTE There is no indication of precedence between IsInterferedByElements and InterferesElements. IFC4 CHANGE New inverse relationship. | X | |
| HasProjections | IfcRelProjectsElement @RelatingElement | S[0:?] | Projection relationship that adds a feature (using a Boolean union) to the IfcBuildingElement. | X | |
| HasOpenings | IfcRelVoidsElement @RelatingBuildingElement | S[0:?] | Reference to the IfcRelVoidsElement relationship that creates an opening in an element. An element can incorporate zero-to-many openings. For each opening, that voids the element, a new relationship IfcRelVoidsElement is generated. | X | |
| IsConnectionRealization | IfcRelConnectsWithRealizingElements @RealizingElements | S[0:?] | Reference to the connection relationship with realizing element. The relationship, if provided, assigns this element as the realizing element to the connection, which provides the physical manifestation of the connection relationship. | X | |
| ProvidesBoundaries | IfcRelSpaceBoundary @RelatedBuildingElement | S[0:?] | Reference to space boundaries by virtue of the objectified relationship IfcRelSpaceBoundary. It defines the concept of an element bounding spaces. | X | |
| ConnectedFrom | IfcRelConnectsElements @RelatedElement | S[0:?] | Reference to the element connection relationship. The relationship then refers to the other element that is connected to this element. | X | |
| ContainedInStructure | IfcRelContainedInSpatialStructure @RelatedElements | S[0:1] | Containment relationship to the spatial structure element, to which the element is primarily associated. This containment relationship has to be hierachical, i.e. an element may only be assigned directly to zero or one spatial structure. | X | |
| HasCoverings | IfcRelCoversBldgElements @RelatingBuildingElement | S[0:?] | Reference to IfcCovering by virtue of the objectified relationship IfcRelCoversBldgElement. It defines the concept of an element having coverings associated. | X | |
| HasSurfaceFeatures | IfcRelAdheresToElement @RelatingElement | S[0:?] | Reference to the IfcRelAdheresToElement relationship that adheres a IfcSurfaceFeature to an element. An element can incorporate zero-to-many surface features in one relationship. | X | |
| IfcFeatureElement | |||||
| IfcFeatureElementAddition | |||||
| ProjectsElements | IfcRelProjectsElement @RelatedFeatureElement | Reference to the IfcRelProjectsElement relationship that uses this IfcFeatureElementAddition to create a volume addition at an element. The IfcFeatureElementAddition can only be used to create a single addition at a single element using Boolean addition operation. | X | ||
| IfcProjectionElement | |||||
| 9 | PredefinedType | IfcProjectionElementTypeEnum | ? |
Predefined generic type for a projection element that is specified in an enumeration. There may be a property set given specificly for the predefined types.
IFC4 CHANGE The attribute has been added at the end of the entity definition. | X |
Property Sets
The Property Sets for Objects concept template applies to this entity as shown in Table 123.
Table 123 — IfcProjectionElement Property Sets for Objects |
Quantity Sets
The Quantity Sets concept template applies to this entity as shown in Table 124.
| ||||
Table 124 — IfcProjectionElement Quantity Sets |
Placement
The Product Local Placement concept template applies to this entity as shown in Table 125.
Table 125 — IfcProjectionElement Product Local Placement |
The local placement for IfcOpeningRecess is defined in its supertype IfcProduct. It is defined by the IfcLocalPlacement, which defines the local coordinate system that is referenced by all geometric representations.
Body Geometry
The Body Geometry concept template applies to this entity as shown in Table 126.
|
|
Table 126 — IfcProjectionElement Body Geometry |
The geometric representation of IfcProjectionElement is defined using the swept area solid geometry. The following attribute values for the IfcShapeRepresentation holding this geometric representation shall be used:
The following additional constraints apply to the swept solid representation:
As shown in Figure 326, the following interpretation of dimension parameter applies for rectangular projection:
NOTE Rectangles are now defined centric, the placement location has to be set: > * IfcCartesianPoint(XDim/2,YDim/2)
NOTE The local placement directions for the IfcProjectionElement are only given as an example, other directions are valid as well.
 |
Figure 326 — Projection representation |
The general b-rep geometric representation of IfcProjectionElement is defined using the Brep geometry. The Brep representation allows for the representation of complex element shape. The following attribute values for the IfcShapeRepresentation holding this geometric representation shall be used:
Instance diagram
<?xml version="1.0" encoding="utf-8"?>
<ConceptRoot xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" uuid="4ec53492-400e-41ab-8451-f32e68a87faa" name="IfcProjectionElement" applicableRootEntity="IfcProjectionElement">
<Applicability>
<Template ref="0c395c35-f7a9-4d40-86a3-38328f274e09" />
<TemplateRules operator="and">
</TemplateRules>
</Applicability>
<Concepts>
<Concept uuid="ef90aec1-def9-4b7d-a23f-e253bcb401c2" name="Property Sets">
<Template ref="f74255a6-0c0e-4f31-84ad-24981db62461" />
</Concept>
<Concept uuid="cba4672b-1f0f-4ae4-ae75-0f2a946d8d46" name="Quantity Sets">
<Template ref="6652398e-6579-4460-8cb4-26295acfacc7" />
<TemplateRules operator="and">
<TemplateRule Parameters="QsetName[Value]='Qto_ProjectionElementBaseQuantities'" />
</TemplateRules>
</Concept>
<Concept uuid="ff4f7b81-82ea-4c67-8015-f76f0906d647" name="Placement">
<Template ref="cbe85b5f-7912-4a43-8bb7-1e63bf40b26d" />
</Concept>
<Concept uuid="fb6cb9e4-ef7f-4cbe-8782-325ca9094283" name="Body Geometry">
<Template ref="c446bd16-2de3-4b97-b34f-4446ac0badc2" />
<TemplateRules operator="and">
<TemplateRule />
<TemplateRule />
</TemplateRules>
</Concept>
</Concepts>
</ConceptRoot>
<xs:element name="IfcProjectionElement" type="ifc:IfcProjectionElement" substitutionGroup="ifc:IfcFeatureElementAddition" nillable="true"/>
<xs:complexType name="IfcProjectionElement">
<xs:complexContent>
<xs:extension base="ifc:IfcFeatureElementAddition">
<xs:attribute name="PredefinedType" type="ifc:IfcProjectionElementTypeEnum" use="optional"/>
</xs:extension>
</xs:complexContent>
</xs:complexType>
ENTITY IfcProjectionElement
SUBTYPE OF (IfcFeatureElementAddition);
PredefinedType : OPTIONAL IfcProjectionElementTypeEnum;
WHERE
CorrectPredefinedType : NOT(EXISTS(PredefinedType)) OR
(PredefinedType <> IfcProjectionElementTypeEnum.USERDEFINED) OR
((PredefinedType = IfcProjectionElementTypeEnum.USERDEFINED) AND EXISTS(SELF\IfcObject.ObjectType));
END_ENTITY;
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