IfcFaceBasedSurfaceModel

Natural language names
deFlächenmodell (basierend auf Einzelflächen)
enFace Based Surface Model
Semantic definitions at the entity
Entity 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.

NOTE  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.
NOTE  Entity adapted from face_based_surface_model defined in ISO 10303-42.
HISTORY  New entity in IFC2x.

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.
IFC4 CHANGE  The entity has been deprecated and shall not be used. The entity IfcFacetedBrep shall be used instead.
Attribute definitions
#AttributeTypeCardinalityDescription C
1FbsmFacesIfcConnectedFaceSetS[1:?] The set of connected face sets comprising the face based surface model.X
Dim
:=3
IfcDimensionCount[1:1]The space dimensionality of this class, it is always 3. X
Inherited definitions from supertypes
Entity inheritance IfcGeometricRepresentationItem IfcRepresentationItem
Attribute inheritance
#AttributeTypeCardinalityDescriptionC
IfcRepresentationItem
LayerAssignmentIfcPresentationLayerAssignment
@AssignedItems
S[0:1]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. X
StyledByItemIfcStyledItem
@Item
S[0:1]Reference to the IfcStyledItem that provides presentation information to the representation, e.g. a curve style, including colour and thickness to a geometric curve. X
IfcGeometricRepresentationItem
IfcFaceBasedSurfaceModel
1FbsmFacesIfcConnectedFaceSetS[1:?] The set of connected face sets comprising the face based surface model.X
Dim
:=3
IfcDimensionCount[1:1]The space dimensionality of this class, it is always 3. X
Examples
Formal representations
XSD Specification
 <xs:element name="IfcFaceBasedSurfaceModel" type="ifc:IfcFaceBasedSurfaceModel" substitutionGroup="ifc:IfcGeometricRepresentationItem" nillable="true"/>
 <xs:complexType name="IfcFaceBasedSurfaceModel">
  <xs:complexContent>
   <xs:extension base="ifc:IfcGeometricRepresentationItem">
    <xs:sequence>
     <xs:element name="FbsmFaces">
      <xs:complexType>
       <xs:sequence>
        <xs:element ref="ifc:IfcConnectedFaceSet" maxOccurs="unbounded"/>
       </xs:sequence>
       <xs:attribute ref="ifc:itemType" fixed="ifc:IfcConnectedFaceSet"/>
       <xs:attribute ref="ifc:cType" fixed="set"/>
       <xs:attribute ref="ifc:arraySize" use="optional"/>
      </xs:complexType>
     </xs:element>
    </xs:sequence>
   </xs:extension>
  </xs:complexContent>
 </xs:complexType>
EXPRESS Specification
ENTITY IfcFaceBasedSurfaceModel
 SUBTYPE OF (IfcGeometricRepresentationItem);
  FbsmFaces : SET [1:?] OF IfcConnectedFaceSet;
 DERIVE
  Dim : IfcDimensionCount := 3;
END_ENTITY;

Link to EXPRESS-G diagram EXPRESS-G diagram

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