8.8.3.17 IfcFaceBasedSurfaceModel
8.8.3.17.1 Semantic definition
The IfcFaceBasedSurfaceModel represents the a shape by connected face sets. The connected faces have a dimensionality 2 and are placed in a coordinate space of dimensionality 3.
Definition according to ISO/CD 10303-42:1992 A face based surface model is described by a set of connected face sets of dimensionality 2. The connected face sets shall not intersect except at edges and vertices, except that a face in one connected face set may overlap a face in another connected face set, provided the face boundaries are identical. There shall be at least one connected face set. A connected face set may exist independently of a surface model. Entity adapted from face_based_surface_model defined in ISO 10303-42. New entity in IFC2x.Informal Propositions
- The connected face sets shall not overlap or intersect except at common faces, edges or vertices.
- The fbsm faces have dimensionality 2.
8.8.3.17.2 Entity inheritance
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- IfcFaceBasedSurfaceModel
- IfcAnnotationFillArea
- IfcBooleanResult
- IfcBoundingBox
- IfcCartesianPointList
- IfcCartesianTransformationOperator
- IfcCsgPrimitive3D
- IfcCurve
- IfcDirection
- IfcFillAreaStyleHatching
- IfcFillAreaStyleTiles
- IfcGeometricSet
- IfcHalfSpaceSolid
- IfcLightSource
- IfcPlacement
- IfcPlanarExtent
- IfcPoint
- IfcSectionedSpine
- IfcSegment
- IfcShellBasedSurfaceModel
- IfcSolidModel
- IfcSurface
- IfcTessellatedItem
- IfcTextLiteral
- IfcVector
8.8.3.17.3 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. The inverse attribute LayerAssignments has been added. 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. The inverse attribute StyledByItem has been added. |
|
| Click to show 2 hidden inherited attributes Click to hide 2 inherited attributes | |||
| IfcFaceBasedSurfaceModel (2) | |||
| 1 | FbsmFaces | SET [1:?] OF IfcConnectedFaceSet |
The set of connected face sets comprising the face based surface model. |
| * | Dim | IfcDimensionCount |
This attribute is formally derived. The space dimensionality of this class, it is always 3. |
8.8.3.17.4 Examples
8.8.3.17.5 Formal representation
ENTITY IfcFaceBasedSurfaceModel
SUBTYPE OF (IfcGeometricRepresentationItem);
FbsmFaces : SET [1:?] OF IfcConnectedFaceSet;
DERIVE
Dim : IfcDimensionCount := 3;
END_ENTITY;