About the Alignment Design Process

This section describes the design process workflow to help you understand the logical steps to follow.

Alignment is the position of the centerline of the road, the highway, or railway on the ground. Horizontal alignment includes straight and curve path. Horizontal alignment is nothing but a transition between two directions. Vertical alignment includes level & gradients. Vertical alignment is the elevation or profile of the centerline of the road. 3D alignment is the combination of horizontal and vertical alignments.

The figure below provides a step-by-step overview of the alignment process workflow:

• 0: Launching the Civil Engineering 3D Design app.
• 1: Setting preferences.
• 2: Specifying design rules using Data Setup.
• 3: Creating a horizontal alignment including specifying alignment points (with various methods), creating an alignment profile, a transition if necessary, connecting alignments, creating a transition curve (connection curve).
• 4: Creating a vertical alignment that involves creating an alignment profile, a connection curve, inserting points, create a report table.
• 5: Creating a 3D alignment that is the combination of horizontal and vertical alignments.
• 7: Generating an alignment report consists in exporting alignment related information to a format of your choice (Excel file or html by default).

This section provides information related to alignments.

An alignment is seen as a reference system associated with linear constructions such as roads, rails, bridges, and used to position elements along itself. It is represented by a horizontal, a vertical alignment and a 3D alignment:

• A horizontal alignment is a sketch containing the geometry of the horizontal alignment.
• A vertical alignment is a sketch containing the geometry of the vertical alignment.
• A 3D alignment is a 3D curve combining horizontal and vertical alignments.

A single alignment can be represented as:

• A horizontal, a vertical, and a resulting 3D alignment,
• Only a horizontal alignment,
• Only a 3D alignment.

A vertical alignment is a sketch in a plane normal to XY containing 2D geometric elements defining the vertical alignment. It must be a continuous, nonbranching 2D wire and it contains points, lines, arcs, and parabolas.

The plane support of the vertical alignment sketch is built by unfolding a horizontal alignment.

Alignment points located on horizontal and vertical alignments are used to help you locate design information.

Alignments can point the following parameters:

Option	Description
Linear Referencing	A set of parameters for point position on alignment: Start point: starting point for distance offset Distance (length): curvilinear distance from start point
Main parameters	A set of parameters for design rules Start/End (Boolean): if the point is the start/end of the alignment. Label (String): custom point identification and labeling. A list of keywords are interpreted and replaced by the following corresponding values: %s: Stationing value %i: Internal point index %I: Start point index (case of Linear Referencing) %d:Curvilinear distance from start point %s: Speed %c: Category Note: By default the label is set to "%s". If you change the default label parameters, they are saved in the preferences setting file for the next point creation. Index (Integer): unique internal number of the alignment point Category (String): category (for example of the road) Speed: design speed from that point
Design rules	Table names (list of Strings): name of the design rules table for this point

Alignment points are specialized construction sketcher points aggregated in horizontal alignment sketches.

In vertical alignments, corresponding unfolded points are automatically generated and intersected with the sketch profile. Alignment points are also generated in 3D alignment and aggregated under a dedicated geometric set.

If an Alignment point is not positioned on the horizontal alignment wire, the point is not transferred in vertical and 3D alignments.

Modifying the position of alignment points in a horizontal alignment sketch automatically updates the corresponding points in vertical and 3D alignments. Similarly, adding or deleting alignment points in horizontal alignment sketches automatically adds or deletes the corresponding points in vertical and 3D alignments.

Design rules let you run design checks when designing your alignment.

These rules verify curve radii, lengths of transition lines, a particular portion of an alignment, or a profile. Rules depend on the speed or road category.

In the 3DEXPERIENCE, you can define design rules in Data Setup. In the Building and Civil Resources resource set, you can set an XML file containing design rules in Alignment Design Rules Definition.

In an XML file, you can define different types of tables. For each type of rules, you can define 0 to N tables. For each table, you can define 1 to N rules. Each rule defines the minimum and/or maximum value depending on the speed or the road category. If no speed or category is defined, the same minimum and/or maximum value is taken into account during the alignment process whatever the speed or category is defined for the alignment.

For more information, see Building and Civil Resources in the Data Setup User's Guide.

Design checks are run when designing horizontal and vertical alignments. They are based on design rules.

Speed, category, and table name information are read from alignment point parameters. Points define the table name to be used for design checks. If a point defines a speed, or a category table name, then it overrides the values defined in previous points. So the speed can vary for the different sections of the alignment.

Stationing is a linear referencing system along a horizontal alignment. It is defined by minor and major interval values.

Stations are reference points positioned at a regular interval along a horizontal alignment. A station interval is defined by the major stationing value.

All points on an alignment can be expressed in the stationing system. For example, a point located at a distance of 253m from the start alignment point has a stationing value of 2+53m with a major stationing of 100m (2x100m + 53m).

Major and minor stationing intervals can be defined in Data Setup. If not, it can be defined on horizontal alignments.

• Start station/distance: starting station or distance of alignment. By default the alignment starts at 0.
• Major interval: major stationing interval defining the regular interval between stations.
• Minor interval: minor stationing interval used to display ticks between each station.

For more information, see Building and Civil Resources in the Data Setup User's Guide.