8.7.3.1 IfcAlignmentCantSegment
8.7.3.1.1 Semantic definition
An IfcAlignmentCantSegment is an individual segment along IfcAlignmentCant. The cant alignment is defined by ordered segments that connect end-to-start. The points defined in a cant alignment segment are defined in a plane with x = distance along horizontal alignment and y = height relative to projected points in vertical alignment. The following cant segment types are defined:
- Bloss transition - IfcAlignmentCantSegmentTypeEnum .BLOSSCURVE.
- Constant cant - IfcAlignmentCantSegmentTypeEnum .CONSTANTCANT.
- Cosine transition - IfcAlignmentCantSegmentTypeEnum .COSINECURVE.
- Helmert transition - IfcAlignmentCantSegmentTypeEnum .HELMERTCURVE.
- Linear transition - IfcAlignmentCantSegmentTypeEnum .LINEARTRANSITION.
- Sine transition - IfcAlignmentCantSegmentTypeEnum SINECURVE
- Viennese Bend (R) transition - IfcAlignmentCantSegmentTypeEnum .VIENNESEBEND.
For each cant segment, the following information is provided: * the start point, defined by distance along the horizontal alignment * the length (as horizontal length along the distance along (not the curve segment length)) * the start cant, given by the values of left cant and right cant, measured relatively to vertical alignment * the end cant, given by the values of left cant and right cant, measured from vertical alignment * the information of tangential continuity that can be used to check continuity of segments (e.g. invalid sudden change of cant or missing cant information if end point and starting point differ over a threshold).
8.7.3.1.2 Entity inheritance
8.7.3.1.3 Attributes
| # | Attribute | Type | Description |
|---|---|---|---|
| IfcAlignmentParameterSegment (2) | |||
| 1 | StartTag | OPTIONAL IfcLabel |
Tag to annotate the start point of the alignment segment. |
| 2 | EndTag | OPTIONAL IfcLabel |
Tag to annotate the end point of the alignment segment. |
| Click to show 2 hidden inherited attributes Click to hide 2 inherited attributes | |||
| IfcAlignmentCantSegment (7) | |||
| 3 | StartDistAlong | IfcLengthMeasure |
Distance along the horizontal alignment, measured along the IfcAlignmentHorizontal given in the length unit of the global IfcUnitAssignment. |
| 4 | HorizontalLength | IfcNonNegativeLengthMeasure |
Length measured as distance along the horizontal alignment of the segment. |
| 5 | StartCantLeft | IfcLengthMeasure |
Length measured for the left cant at the beginning of the segment. |
| 6 | EndCantLeft | OPTIONAL IfcLengthMeasure |
Length measured for the left cant at the end of the segment. |
| 7 | StartCantRight | IfcLengthMeasure |
Length measured for the right cant at the beginning of the segment. |
| 8 | EndCantRight | OPTIONAL IfcLengthMeasure |
Length measured for the right cant at the end of the segment. |
| 9 | PredefinedType | IfcAlignmentCantSegmentTypeEnum |
A list of types to further identify the object. Some property sets may be specifically applicable to one of these types. |
8.7.3.1.4 Examples
8.7.3.1.5 Formal representation
ENTITY IfcAlignmentCantSegment
SUBTYPE OF (IfcAlignmentParameterSegment);
StartDistAlong : IfcLengthMeasure;
HorizontalLength : IfcNonNegativeLengthMeasure;
StartCantLeft : IfcLengthMeasure;
EndCantLeft : OPTIONAL IfcLengthMeasure;
StartCantRight : IfcLengthMeasure;
EndCantRight : OPTIONAL IfcLengthMeasure;
PredefinedType : IfcAlignmentCantSegmentTypeEnum;
END_ENTITY;