平面范围定义沿二维坐标系的两个轴的范围，而不受其位置的影响。如果在三维坐标系中使用平面范围，则它定义沿x和y轴的范围。
注：实体改编自ISO10303-46中定义的平面_范围
IFC2x2中增加的新实体。
| # | 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 | |||||
| IfcPlanarExtent | |||||
| 1 | SizeInX | IfcLengthMeasure | [1:1] | The extent in the direction of the x-axis. | X |
| 2 | SizeInY | IfcLengthMeasure | [1:1] | The extent in the direction of the y-axis. | X |
EXPRESS Specification
ENTITY IfcPlanarExtent
SUPERTYPE OF(IfcPlanarBox)
SUBTYPE OF (IfcGeometricRepresentationItem);
SizeInX : IfcLengthMeasure;
SizeInY : IfcLengthMeasure;
END_ENTITY;