Alignment Data
- Alignment
- Curve used to
define a reference system to position elements for linear
construction works, such as roads, rails, bridges, and others. It can be defined as:
- A
horizontal, a vertical and a 3D alignment.
- A
horizontal and a vertical alignment (the 3D alignment curve can be
calculated from horizontal (in XY plan) and vertical (along the
horizontal alignment / Z coordinate space) alignments)
- Only a horizontal alignment
- Only a 3D alignment (for example from surveying).
- Horizontal Alignment
- 2D
continuous, non-branching wire composed of connected curve
segments that represents the linear geometry of the
road/railway/tunnel in XY plane. It is also called "Center line" or
"Red line".
- Vertical Alignment
- 2D
continuous, non-branching wire composed of connected curve
segments that represents the elevation (i.e. height) profile of the
road/railway/tunnel along the horizontal alignment in the plane normal to XY.
- 3D Alignment
- 3D curve that
represents an alignment. The 3D alignment curve can be computed
from horizontal and vertical alignments.
Alignment in Building and Civil Assemblies
- Alignment set
- Private geometrical set containing all alignment entities.
- Alignment
- Refers to a horizontal alignment and contains a vertical alignment and the resulting 3D alignment. Several alignments can reference the same horizontal alignment.
- Horizontal alignment
- Sketch containing geometry of the horizontal alignment.
- Vertical alignment
- Sketch containing geometry of the vertical alignment.
- 3D alignment
- 3D curve combination of horizontal and vertical alignments.
Note:
In Building and Civil Assemblies, the 3D alignment is always calculated on the fly from 2D alignments (horizontal and vertical alignments). - The 3D Alignment is not editable.
- It is automatically recalculated from changes made in the 2D alignments.
- An IFC file that only contains 3D alignment data (no 2D alignment) is not fully imported to Building and Civil Assemblies.
- 3D Alignment curves are not exported.
IFC Alignment Entities
- IfcLinearPositioningElement
- Abstract entity definition for linear positioning elements that are used to position other elements relatively. It allows any type of bounded curve as linear element.
- IfcAlignment
- Instantiable entity to represent an alignment. As a reminder, an alignment is a linear positioning element for using a linear referencing method to position other items.
- IfcBoundedCurve
- Abstract entity to represent a bounded curve. A bounded curve is a curve of finite arc length with identifiable end points.
- IfcAlignmentCurve
- Instantiable bounded curve that encapsulates vertical and horizontal alignments. As a reminder, an instance of IfcAlignmentCurve must contain a horizontal alignment.
- IfcAlignment2DHorizontal
- Instantiable IFC entity that represents a linear reference projected onto the horizontal x/y plane.
- IfcAlignment2DVertical
- Instantiable IFC entity that represents a height profile along the horizontal alignment.
- IfcAlignment2DVerticalSegment
- Abstract IFC entity to represent an individual line/arc segment along the IfcAlignment2DVertical, being defined in the distance-along/z coordinate space.
- IfcAlignment2DHorizontalSegment
- Instantiable entity to represent an individual line/arc segment along the IfcAlignment2DHorizontal, being defined in the x/y coordinate space.
Mapping
| IFC Entity | Building and Civil Assemblies |
|---|
| IfcAlignmentCurve | Alignment |
| IfcAlignment | Alignment |
| IfcAlignment2DHorizontal | 2D horizontal
alignment |
| IfcAlignment2DVertical | 2D vertical
alignment |
| IfcAlignment2DHorizontalSegment | 2D horizontal sketch
element |
| IfcAlignment2DVerticalSegment | 2D vertical sketch
element |
By default at import, vertical alignment is hidden, horizontal alignment is visible.