IfcFaceBasedSurfaceModel

Definition from 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.

> NOTE Corresponding STEP entity: face_based_surface_model. Please refer to ISO/IS 10303-42:1994, p. 188 for the final definition of the formal standard.

> HISTORY: New type in IFC Release 2x
> ISSUE: See issue and change log for changes made in IFC Release 2x

Informal propositions:

1. The connected face sets shall not overlap or intersect except at common faces, edges or vertices.
2. The fbsm faces have dimensionality 2.

EXPRESS specification:

ENTITY IfcFaceBasedSurfaceModel
SUBTYPE OF ( | IfcGeometricRepresentationItem);
FbsmFaces | : | SET [1:?] OF IfcConnectedFaceSet;
DERIVE
Dim | : | IfcDimensionCount := 3;
END_ENTITY;

Attribute definitions:

FbsmFaces | : | The set of connected face sets comprising the face based surface model.
Dim | : | The space dimensionality of this class, it is always 3.

Inheritance graph

ENTITY IfcFaceBasedSurfaceModel;
ENTITY IfcRepresentationItem;
INVERSE
LayerAssignments | : | SET OF IfcPresentationLayerAssignment FOR AssignedItems;
StyledByItem | : | SET [0:1] OF IfcStyledItem FOR Item;
ENTITY IfcGeometricRepresentationItem;
ENTITY IfcFaceBasedSurfaceModel;
FbsmFaces | : | SET [1:?] OF IfcConnectedFaceSet;
DERIVE
Dim | : | IfcDimensionCount := 3;
END_ENTITY;