IfcAnnotation

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	C
	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	C
IfcRoot
1	GlobalId	IfcGloballyUniqueId	[1:1]	Assignment of a globally unique identifier within the entire software world.	X
2	OwnerHistory	IfcOwnerHistory	[0:1]	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.	X
3	Name	IfcLabel	[0:1]	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	[0:1]	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).	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).	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.	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).	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).	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	[0:1]	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.	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.	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.	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.	X
IfcProduct
6	ObjectPlacement	IfcObjectPlacement	[0:1]	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	[0:1]	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
IfcAnnotation
	ContainedInStructure	IfcRelContainedInSpatialStructure @RelatedElements	S[0:1]	Relationship to a spatial structure element, to which the associate is primarily associated.	X

Definitions applying to Common Use Definitions

Instance diagram

Concept usage

Property Sets for Objects

The Property Sets for Objects concept applies to this entity as shown in Table 20.

PredefinedType	Name	Properties
ContourLine	Pset_AnnotationContourLine
LineOfSight	Pset_AnnotationLineOfSight
SurveyArea	Pset_AnnotationSurveyArea
Sound	Pset_SoundAttenuation

Table 20 — IfcAnnotation Property Sets for Objects

Annotation 2D Geometry

The Annotation 2D Geometry concept applies to this entity as shown in Table 21.

Identifier	Type	Items	Description
Annotation	Annotation2D	IfcGeometricCurveSet	Any point or curve
Annotation	Annotation2D	IfcAnnotationFillArea	Area for hatching
Annotation	Annotation2D	IfcTextLiteral	Text literal for applying text

Table 21 — IfcAnnotation Annotation 2D Geometry

Annotation 3D Geometry

The Annotation 3D Geometry concept applies to this entity as shown in Table 22.

Identifier	Type	Items	Description
Annotation	GeometricSet	IfcGeometricSet	Any point, curve or surface representing the annotation.

Table 22 — IfcAnnotation Annotation 3D Geometry

Concept inheritance

#	Concept	Model View
IfcRoot
	Software Identity	Common Use Definitions
	Revision Control	Common Use Definitions
IfcObject
	Object Occurrence Predefined Type	Common Use Definitions
IfcAnnotation
	Property Sets for Objects	Common Use Definitions
	Annotation 2D Geometry	Common Use Definitions
	Annotation 3D Geometry	Common Use Definitions

Formal representations

XSD 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

Link to this page

Item	Change	Description
IFC2x3 to IFC4
IfcAnnotation
OwnerHistory	MODIFIED	Instantiation changed to OPTIONAL.

	Zeichnungselement / Erläuterung im Modell
	Annotation
	Annotation