8.8.3.38 IfcShellBasedSurfaceModel

8.8.3.38.1 Semantic definition

An IfcShellBasedSurfaceModel represents the shape by a set of open or closed shells. The connected faces within the shell have a dimensionality 2 and are placed in a coordinate space of dimensionality 3.

Informal Propositions

The dimensionality of the shell based surface model is 2.
The shells shall not overlap or intersect except at common faces, edges or vertices.

8.8.3.38.2 Entity inheritance

8.8.3.38.3 Attributes

#	Attribute	Type	Description
IfcRepresentationItem (2)
	LayerAssignment	SET [0:1] OF IfcPresentationLayerAssignment FOR AssignedItems	Assignment of the representation item to a single or multiple layer(s). The LayerAssignments can override a LayerAssignments of the IfcRepresentation it is used within the list of Items. IFC2x3-CHANGE The inverse attribute LayerAssignments has been added. IFC4-CHANGE The inverse attribute LayerAssignment has been restricted to max 1. Upward compatibility for file based exchange is guaranteed.
	StyledByItem	SET [0:1] OF IfcStyledItem FOR Item	Reference to the IfcStyledItem that provides presentation information to the representation, e.g. a curve style, including colour and thickness to a geometric curve. IFC2x3-CHANGE The inverse attribute StyledByItem has been added.
Click to show 2 hidden inherited attributes
IfcShellBasedSurfaceModel (2)
1	SbsmBoundary	SET [1:?] OF IfcShell	No description available.
*	Dim	IfcDimensionCount	This attribute is formally derived. `3` The space dimensionality of this class, it is always 3.

Table 8.8.3.38.A

8.8.3.38.4 Formal representation

 ENTITY IfcShellBasedSurfaceModel
 SUBTYPE OF (IfcGeometricRepresentationItem);
	SbsmBoundary : SET [1:?] OF IfcShell;
 DERIVE
	 Dim : IfcDimensionCount := 3;
END_ENTITY;

8.8.3.38.5 References

IfcGeometricRepresentationItem

	ENTITY IfcShellBasedSurfaceModel
	SUBTYPE OF (IfcGeometricRepresentationItem);
	SbsmBoundary : SET [1:?] OF IfcShell;
	DERIVE
	Dim : IfcDimensionCount := 3;
	END_ENTITY;