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
- 
- IfcShellBasedSurfaceModel
 - IfcAnnotationFillArea
 - IfcBooleanResult
 - IfcBoundingBox
 - IfcCartesianPointList
 - IfcCartesianTransformationOperator
 - IfcCsgPrimitive3D
 - IfcCurve
 - IfcDirection
 - IfcFaceBasedSurfaceModel
 - IfcFillAreaStyleHatching
 - IfcFillAreaStyleTiles
 - IfcGeometricSet
 - IfcHalfSpaceSolid
 - IfcLightSource
 - IfcPlacement
 - IfcPlanarExtent
 - IfcPoint
 - IfcSectionedSpine
 - IfcSegment
 - IfcSolidModel
 - IfcSurface
 - IfcTessellatedItem
 - IfcTextLiteral
 - IfcVector
 
 
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.  | 
|
| 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.  | 
|
| Click to show 2 hidden inherited attributes Click to hide 2 inherited attributes | |||
| IfcShellBasedSurfaceModel (2) | |||
| 1 | SbsmBoundary | SET [1:?] OF IfcShell | 
 No description available.  | 
| * | Dim | IfcDimensionCount | 
 This attribute is formally derived. 
The space dimensionality of this class, it is always 3.  | 
8.8.3.38.4 Formal representation
ENTITY IfcShellBasedSurfaceModel
 SUBTYPE OF (IfcGeometricRepresentationItem);
	SbsmBoundary : SET [1:?] OF IfcShell;
 DERIVE
	 Dim : IfcDimensionCount := 3;
END_ENTITY;