5.4.3.1 IfcAnnotation

	Annotation
	Zeichnungselement / Erläuterung im Modell

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.

HISTORY  New entity in IFC2x2.

Attribute use definition

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.
    

Construction Operations

 Instance diagram

The Identity concept applies to this entity.

Exchange
Import						O	O	O	O
Export						O	O	O	O

The Revision Control concept applies to this entity.

Exchange
Import						O	O	O	O
Export						O	O	O	O

The External Data Constraints concept applies to this entity as shown in Table 13.

Table Name Reference Format Color Coordinate Name IfcAnnotation.Name     Coordinate CreatedBy IfcAnnotation.OwnerHistory\IfcOwnerHistory.OwningUser\IfcPersonAndOrganization.ThePerson\IfcPerson.Identification     Coordinate CreatedOn IfcAnnotation.OwnerHistory\IfcOwnerHistory.CreationDate     Coordinate Category IfcAnnotation.HasAssociations[*]\IfcRelAssociatesClassification.RelatingClassification\IfcClassificationReference.Identification     Coordinate SheetName IfcAnnotation.HasAssignments\IfcRelAssignedToProduct.RelatingProduct\ Key   Coordinate RowName IfcAnnotation.HasAssignments\IfcRelAssignedToProduct.RelatingProduct Key   Coordinate CoordinateXAxis IfcAnnotation.ObjectPlacement\IfcLocalPlacement.RelativePlacement\IfcAxis2Placement3D.Location\IfcCartesianPoint.Coordinates[1]     Coordinate CoordinateYAxis IfcAnnotation.ObjectPlacement\IfcLocalPlacement.RelativePlacement\IfcAxis2Placement3D.Location\IfcCartesianPoint.Coordinates[2]     Coordinate CoordinateZAxis IfcAnnotation.ObjectPlacement\IfcLocalPlacement.RelativePlacement\IfcAxis2Placement3D.Location\IfcCartesianPoint.Coordinates[3]     Coordinate ExtSystem IfcAnnotation.OwnerHistory\IfcOwnerHistory.OwningApplication\IfcApplication.ApplicationIdentifier     Coordinate ExtObject       Coordinate ExtIdentifier IfcAnnotation.GlobalId     Coordinate ClockwiseRotation       Coordinate ElevationalRotation       Coordinate YawRotation

Table 13 — IfcAnnotation External Data Constraints

Exchange
Import						O	O	O	O
Export						O	O	O	O

XSD Specification:

EXPRESS Specification:

Attribute Definitions:

Inheritance Graph:

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