IfcRectangularPyramid是一个构造实体几何（CSG）三维基本体。它是一个有一个矩形底部和一个叫做顶点的点作为顶部的实体。从底部到顶部逐渐变细。从基部中心到顶点的轴垂直于基部。继承的位置属性定义IfcAxisPlacement3D，并提供棱锥体的位置和方向：
SELFIfcCsgPrimitive3D.Position：基本体的轴系统的位置和方向。
SELFIfcCsgPrimitive3D。位置。位置：圆形区域的中心是圆锥体的底面。
SELFIfcCsgPrimitive3D。位置。位置[3] ：继承的放置坐标系的z轴提供IfcRightCircularCone的中心轴，顶点位于应用于z轴正方向的高度值处。底半径定义放置坐标系xy平面上的圆形底面。
如图所示，金字塔位于其自身的放置坐标系内。原点是位于XY平面的底部矩形的中心。顶点位于正z轴上[0，0，Height]。
纹理使用定义
在每个三角形侧面上，纹理都是垂直对齐的。纹理根据重复被拉伸或重复到每个面的底部。根据Repeat T向顶点拉伸或重复纹理，如果Repeat为False，则顶点的坐标为（0.5,1.0）。
在底面上，纹理前后对齐。
下图说明了使用钳制纹理的默认纹理映射（RepeatS=False和RepeatT=False）。左侧的图像显示了S轴指向右侧而T轴指向上方的纹理。右侧的图像显示应用于几何体的纹理，其中X轴指向右侧，Y轴指向左侧，Z轴指向上方。
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Rectangular pyramid textures |
| # | 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 | |||||
| IfcCsgPrimitive3D | |||||
| 1 | Position | IfcAxis2Placement3D | [1:1] | The placement coordinate system to which the parameters of each individual CSG primitive apply. | X |
| Dim :=3 |
IfcDimensionCount | [1:1] | The space dimensionality of this geometric representation item, it is always 3. | X | |
| IfcRectangularPyramid | |||||
| 2 | XLength | IfcPositiveLengthMeasure | [1:1] | The length of the base measured along the placement X axis. It is provided by the inherited axis placement through SELFIfcCsgPrimitive3D.Position.P[1]. | X |
| 3 | YLength | IfcPositiveLengthMeasure | [1:1] | The length of the base measured along the placement Y axis. It is provided by the inherited axis placement through SELFIfcCsgPrimitive3D.Position.P[2]. | X |
| 4 | Height | IfcPositiveLengthMeasure | [1:1] | The height of the apex above the plane of the base, measured in the direction of the placement Z axis, the SELFIfcCsgPrimitive3D.Position.P[2]. | X |
EXPRESS Specification
ENTITY IfcRectangularPyramid
SUBTYPE OF (IfcCsgPrimitive3D);
XLength : IfcPositiveLengthMeasure;
YLength : IfcPositiveLengthMeasure;
Height : IfcPositiveLengthMeasure;
END_ENTITY;