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IfcDirection

时间:2020-07-14 16:29:06      阅读:47      评论:0      收藏:0      [点我收藏+]

标签:spec   type   ESS   大小   des   span   图片   body   sizeof   

ifc方向提供二维或三维空间中的方向,具体取决于所提供的方向比率的数量。ifc方向并不意味着矢量长度,方向比也不必标准化。

注:定义根据ISO/CD 10303-42:1992

此实体定义二维或三维空间中的一般方向向量。分量的实际大小对定义的方向没有影响,只有X:Y:Z或X:Y的比值才有意义。

请注意,此实体的组件未规范化。如果需要单位矢量,则应在使用前对其进行规范化。

注:实体改编自ISO 10303-42中定义的方向。

IFC1.0中增加的新实体

 

Formal Propositions

RuleDescription
MagnitudeGreaterZero The magnitude of the direction vector shall be greater than zero.
 

 

 

技术图片

 

 

#AttributeTypeCardinalityDescriptionC
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
IfcDirection
1 DirectionRatios IfcReal L[2:3] The components in the direction of X axis (DirectionRatios[1]), of Y axis (DirectionRatios[2]), and of Z axis (DirectionRatios[3]) X
  Dim
:=HIINDEX(DirectionRatios)
IfcDimensionCount [1:1] The space dimensionality of this class, defined by the number of real in the list of DirectionRatios. X
EXPRESS Specification
ENTITY IfcDirection
 SUBTYPE OF (IfcGeometricRepresentationItem);
  DirectionRatios : LIST [2:3] OF IfcReal;
 DERIVE
  Dim : IfcDimensionCount := HIINDEX(DirectionRatios);
 WHERE
  MagnitudeGreaterZero : SIZEOF(QUERY(Tmp <* DirectionRatios | Tmp <> 0.0)) > 0;
END_ENTITY;

 

IfcDirection

标签:spec   type   ESS   大小   des   span   图片   body   sizeof   

原文地址:https://www.cnblogs.com/herd/p/13299627.html

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