IFC 4.3.0.1 (IFC4X3) development

4.10.6 Project Representation Context

A project representation context indicates the coordinate system orientation, direction of true north, precision, and other values that apply to all geometry within a project or project library. A main geometric representation context is created for 3D model, and 2D representations, both can be further refined using geometric representation sub contexts.

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 IfcContext IfcContext 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] 6. LongName [0:1] 7. Phase [0:1] 8. RepresentationContexts [1:?] 9. UnitsInContext [0:1]      IsDefinedBy [0:?]      Declares [0:?] IfcGeometricRepresentationContext IfcGeometricRepresentationContext ContextIdentifier 1. ContextIdentifier [0:1] ContextType 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] IfcContext:RepresentationContexts1->IfcGeometricRepresentationContext:IfcGeometricRepresentationContext0 IfcLabel_5 IfcLabel IfcContext:Phase1->IfcLabel_5:IfcLabel0 IfcLabel_6 IfcLabel IfcContext:ObjectType1->IfcLabel_6:IfcLabel0 IfcLabel_7 IfcLabel IfcContext:LongName1->IfcLabel_7:IfcLabel0 IfcLabel_0 IfcLabel IfcGeometricRepresentationContext:ContextIdentifier1->IfcLabel_0:IfcLabel0 IfcLabel_1 IfcLabel IfcGeometricRepresentationContext:ContextType1->IfcLabel_1:IfcLabel0 IfcDimensionCount IfcDimensionCount IfcGeometricRepresentationContext:CoordinateSpaceDimension1->IfcDimensionCount:IfcDimensionCount0 IfcAxis2Placement3D IfcAxis2Placement3D      LayerAssignment [0:1]      StyledByItem [0:1] 1. Location [1:1] 2. Axis [0:1] 3. RefDirection [0:1] IfcGeometricRepresentationContext:WorldCoordinateSystem1->IfcAxis2Placement3D:IfcAxis2Placement3D0 IfcDirection_2 IfcDirection      LayerAssignment [0:1]      StyledByItem [0:1] 1. DirectionRatios [2:3] IfcGeometricRepresentationContext:TrueNorth1->IfcDirection_2:IfcDirection0 IfcGeometricRepresentationSubContext IfcGeometricRepresentationSubContext SubContextIdentifier 1. ContextIdentifier [0:1] SubContextType 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] 7. ParentContext [1:1] 8. TargetScale [0:1] 9. TargetView [1:1] 10. UserDefinedTargetView [0:1] IfcGeometricRepresentationContext:HasSubContexts1->IfcGeometricRepresentationSubContext:ParentContext0 IfcCartesianPoint IfcCartesianPoint      LayerAssignment [0:1]      StyledByItem [0:1] 1. Coordinates [1:3] IfcAxis2Placement3D:Location1->IfcCartesianPoint:IfcCartesianPoint0 IfcDirection_0 IfcDirection      LayerAssignment [0:1]      StyledByItem [0:1] 1. DirectionRatios [2:3] IfcAxis2Placement3D:Axis1->IfcDirection_0:IfcDirection0 IfcDirection_1 IfcDirection      LayerAssignment [0:1]      StyledByItem [0:1] 1. DirectionRatios [2:3] IfcAxis2Placement3D:RefDirection1->IfcDirection_1:IfcDirection0 IfcLabel_2 IfcLabel IfcGeometricRepresentationSubContext:ContextIdentifier1->IfcLabel_2:IfcLabel0 IfcLabel_3 IfcLabel IfcGeometricRepresentationSubContext:ContextType1->IfcLabel_3:IfcLabel0 IfcPositiveRatioMeasure IfcPositiveRatioMeasure IfcGeometricRepresentationSubContext:TargetScale1->IfcPositiveRatioMeasure:IfcPositiveRatioMeasure0 IfcGeometricProjectionEnum IfcGeometricProjectionEnum IfcGeometricRepresentationSubContext:TargetView1->IfcGeometricProjectionEnum:IfcGeometricProjectionEnum0 IfcLabel_4 IfcLabel IfcGeometricRepresentationSubContext:UserDefinedTargetView1->IfcLabel_4:IfcLabel0
Figure 4.10.6.A

General Usage

ApplicableEntity
ContextIdentifier
IfcGeometricRepresentationContext.ContextIdentifier
ContextType
IfcGeometricRepresentationContext.ContextType
IfcProject Model 3D
IfcProject Plan 2D
Table 4.10.6.B

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