实体定义：
分析曲面的公共超类型中的一个ifcelementary曲面。
注：定义根据ISO/CD 10303-42:1992
定义了一个简单的解析曲面。
注：实体改编自ISO 10303-42中定义的基本表面。
IFC1.5中增加的新实体
Attribute definitions
| # | Attribute | Type | Cardinality | Description | C |
|---|---|---|---|---|---|
| 1 | Position | IfcAxis2Placement3D | [1:1] | The position and orientation of the surface. This attribute is used in the definition of the parameterization of the surface. | X |
| # | Attribute | Type | Cardinality | Description | C |
|---|---|---|---|---|---|
| IfcRepresentationItem | |||||
| LayerAssignment | IfcPresentationLayerAssignment @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 | |
| StyledByItem | IfcStyledItem @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 | |||||
| IfcSurface | |||||
| Dim :=3 |
IfcDimensionCount | [1:1] | The space dimensionality of IfcSurface. It is always a three-dimensional geometric representation item. | X | |
| IfcElementarySurface | |||||
| 1 | Position | IfcAxis2Placement3D | [1:1] | The position and orientation of the surface. This attribute is used in the definition of the parameterization of the surface. | X |
EXPRESS Specification
ENTITY IfcElementarySurface
ABSTRACT SUPERTYPE OF(ONEOF(IfcCylindricalSurface, IfcPlane))
SUBTYPE OF (IfcSurface);
Position : IfcAxis2Placement3D;
END_ENTITY;