IFC 4.3.0.1 (IFC4X3) development

4.8.1.16 Topography Geometry

Elements describing surface contours may provide a 'Topography' representation. This representation consists of IfcCartesianPointList3D containing a set of points (in no particular order) having unique horizontal coordinates (X and Y axes), with potentially variable vertical coordinates (Z axis). This representation may also contain optional breaklines using IfcIndexedPolyCurve.

The following diagram shows the generic classes and relationships used when applying this concept. In addition, concepts may have particular importance to common or standardised industry practices and scenarios. For these specific usage scenarios, the tables below shows a recommended list of general usage patterns that users may adopt.

G IfcProduct IfcProduct 1. GlobalId [1:1] 2. OwnerHistory [0:1] 3. Name [0:1] 4. Description [0:1]      HasAssignments [0:?]      Nests [0:1]      IsNestedBy [0:?]      HasContext [0:1]      IsDecomposedBy [0:?]      Decomposes [0:1]      HasAssociations [0:?] 5. ObjectType [0:1]      IsDeclaredBy [0:1]      Declares [0:?]      IsTypedBy [0:1]      IsDefinedBy [0:?] 6. ObjectPlacement [0:1] 7. Representation [0:1]      ReferencedBy [0:?]      PositionedRelativeTo [0:?]      ReferencedInStructures [0:?] IfcProductDefinitionShape IfcProductDefinitionShape 1. Name [0:1] 2. Description [0:1] 3. Representations [1:?]      ShapeOfProduct [1:?]      HasShapeAspects [0:?] IfcProduct:Representation1->IfcProductDefinitionShape:IfcProductDefinitionShape0 IfcShapeRepresentation IfcShapeRepresentation 1. ContextOfItems [1:1] Identifier 2. RepresentationIdentifier [0:1] Type 3. RepresentationType [0:1] 4. Items [1:?]      RepresentationMap [0:1]      LayerAssignments [0:?]      OfProductRepresentation [0:?]      OfShapeAspect [0:1] IfcProductDefinitionShape:Representations1->IfcShapeRepresentation:IfcShapeRepresentation0 IfcGeometricRepresentationContext IfcGeometricRepresentationContext 1. ContextIdentifier [0:1] 2. ContextType [0:1]      RepresentationsInContext [0:?] 3. CoordinateSpaceDimension [1:1] 4. Precision [0:1] 5. WorldCoordinateSystem [1:1] 6. TrueNorth [0:1]      HasSubContexts [0:?]      HasCoordinateOperation [0:1] IfcShapeRepresentation:ContextOfItems1->IfcGeometricRepresentationContext:IfcGeometricRepresentationContext0 IfcLabel_0 IfcLabel IfcShapeRepresentation:RepresentationIdentifier1->IfcLabel_0:IfcLabel0 IfcLabel_1 IfcLabel IfcShapeRepresentation:RepresentationType1->IfcLabel_1:IfcLabel0 IfcCartesianPointList3D_0 IfcCartesianPointList3D      LayerAssignment [0:1]      StyledByItem [0:1] 1. CoordList [1:?] 2. TagList [1:?] IfcShapeRepresentation:Items1->IfcCartesianPointList3D_0:IfcCartesianPointList3D0 IfcIndexedPolyCurve IfcIndexedPolyCurve      LayerAssignment [0:1]      StyledByItem [0:1] 1. Points [1:1] 2. Segments [1:?] 3. SelfIntersect [1:1] IfcShapeRepresentation:Items1->IfcIndexedPolyCurve:IfcIndexedPolyCurve0 IfcLengthMeasure IfcLengthMeasure IfcCartesianPointList3D_0:CoordList1->IfcLengthMeasure:IfcLengthMeasure0 IfcCartesianPointList3D_1 IfcCartesianPointList3D      LayerAssignment [0:1]      StyledByItem [0:1] 1. CoordList [1:?] 2. TagList [1:?] IfcIndexedPolyCurve:Points1->IfcCartesianPointList3D_1:IfcCartesianPointList3D0 IfcBoolean IfcBoolean IfcIndexedPolyCurve:SelfIntersect1->IfcBoolean:IfcBoolean0 IfcArcIndex IfcArcIndex IfcIndexedPolyCurve:Segments1->IfcArcIndex:IfcArcIndex0 IfcLineIndex IfcLineIndex IfcIndexedPolyCurve:Segments1->IfcLineIndex:IfcLineIndex0
Figure 4.8.1.16.A

General Usage

ApplicableEntity
IfcGeotechnicalStratum
Table 4.8.1.16.B

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