IfcAnnotation

BACnet MVD

#### IfcAnnotation

Natural language names

| Zeichnungselement / Erläuterung im Modell
| Annotation
| Annotation

Change log

Item | SPF | XML | Change | Description
--- | --- | --- | --- | ---
IFC2x3 to IFC4
IfcAnnotation |  |  |  |
OwnerHistory |  |  | MODIFIED | Instantiation changed to OPTIONAL.

##### Semantic definitions at the entity

Entity definition

An annotation is a graphical representation within the geometric (and spatial) context of a project, that adds a note or meaning to the objects which constitutes the project model. Annotations include additional points, curves, text, dimensioning, hatching and other forms of graphical notes. It also include symbolic representations of additional model components, not representing products or spatial structures, such as survey points, contour lines or similar.

> NOTE Additional presentation information (often 2D) such as tag number or hatching, that is directly related to a particular product representation is included within the IfcProductDefinitionShape having various IfcShapeRepresentation's of the IfcElement (and its subtypes). Only those presentation information, that cannot be directly related to a single product, have to be wrapped within the IfcAnnotation.

If available, the annotation should be related to the spatial context of the project, by containing the annotation within the appropriate level of the building structure (site, building, storey, or space). This is handled by the IfcRelContainedInSpatialStructure relationship.

The IfcAnnotation can provide specific 0D, 1D, and 2D geometric items as representation of the annotation, offering annotation point, curves, and surfaces. The following values shall be used for the ObjectType.

- 'Annotation point' is an annotation provided by a point that has additional semantic. The inherited attribute ObjectType should be used to capture the type of point annotation, some predefined values are:
  - 'SurveyPoint: A single survey point represented by a Cartesian point. A property set may add the conditions (method, accurracy, etc. to the survey point).
  - 'SurveyArea': A set of survey points represented by Cartesian point. These coordinates are determined relative to the coordinates of a reference point, which acts as the datum for the survey. Properties attached apply equally to all points. The difference in elevation of the survey points enables terrain to be determined.
- 'Annotation curve' is an annotation provided by a curve that has additional semantic. The inherited attribute ObjectType should be used to capture the type of curve annotation, some predefined values are:
  - 'ContourLine': A line of constant elevation typically used on geographic maps where the spacing of lines at constant intervals of elevation may be used as an indication of slope.
  - 'IsoBar': A line of constant pressure typically used on weather maps or to show pressure gradient in spaces, chambers or externally.
  - 'IsoLux': A line of constant illumination typically used to show the distribution of illumination levels and/or daylighting in a space or externally.
  - 'IsoTherm': A line of constant temperature typically used to show the distribution and effect of heating or cooling within a space or to show temperature distribution on a geographic map.
- 'Annotation surface' is an annotation provided by a surface that has additional semantic. The inherited attribute ObjectType should be used to capture the type of surface annotation, some predefined values are:
  - 'SurveyArea': A surface patch based on survey points.

> HISTORY New entity in IFC2x2.

Attribute definitions

# | Attribute | Type | Cardinality | Description | B
--- | --- | --- | --- | --- | ---
| ContainedInStructure | IfcRelContainedInSpatialStructure @RelatedElements | S[0:1] | Relationship to a spatial structure element, to which the associate is primarily associated. |  | 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
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

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

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

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 | 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

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 | 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 | 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
IfcAnnotation
| ContainedInStructure | IfcRelContainedInSpatialStructure @RelatedElements | S[0:1] | Relationship to a spatial structure element, to which the associate is primarily associated. |  | 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="IfcAnnotation" type="ifc:IfcAnnotation" substitutionGroup="ifc:IfcProduct" nillable="true"/>
<xs:complexType name="IfcAnnotation">
<xs:complexContent>
<xs:extension base="ifc:IfcProduct"/>
</xs:complexContent>
</xs:complexType>
`
EXPRESS Specification
`ENTITY IfcAnnotation
SUBTYPE OF (IfcProduct);
INVERSE
ContainedInStructure : SET [0:1] OF IfcRelContainedInSpatialStructure FOR RelatedElements;
END_ENTITY;

EXPRESS-G diagram

`

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