IfcRectangularPyramid

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。

Side	Normal	Origin X	Origin Y	Origin Z	S Axis	T Axis
Left	-X	0	+YLength	0	-Y	(towards top point)
Right	+X	+Xlength	0	0	+Y	(towards top point)
Front	-Y	0	0	0	+X	(towards top point)
Back	+Y	+XLength	+YLength	0	-X	(towards top point)
Bottom	-Z	+XLength	0	0	-X	+Y

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;