Alignment objects can represent road centerlines, pipe networks, and other construction baselines. Creating and defining a horizontal alignment is one of the first steps in roadway, railroad, or site design. You can draw the alignment geometry as a polyline, and then create the named alignment from that geometry. For greater control, you can create an alignment object using the Alignment Layout Tools. You can also make edits to alignments using grips, or the commands on the Alignment Layout Tools toolbar, while automatically maintaining tangency between the alignment components.
For information on recommended workflows when working with alignments, see Alignments Workflow.
Topics in this section
- Understanding Alignments
You create alignments as a combination of lines, curves, and spirals that are viewed as one object.
- Alignment Settings
You can use alignment settings to specify the default behavior for alignment commands.
- Alignment Properties
You can use the Alignment Properties dialog box to assign a name, style, and other properties to the alignment.
- Criteria-Based Alignment Design
Use the criteria-based design feature to apply agency-specific standards to an alignment.
- Alignment Styles
You can use Alignment Styles to control the visual display of each alignment component.
- Alignment Points of Intersection
Points of intersection show the relationships between the tangents and curve groups in an alignment.
- Creating Alignments
Create alignments in many ways using AutoCAD Civil 3D, such as creating them from polylines, and using the Alignment Layout Tools.
- Widenings
You can apply widening for a specified length along an alignment.
- Adding Lines, Curves, and Spirals to an Alignment
Use the constraint-based commands on the Alignment Layout Tools toolbar, to add a fixed entity , a free entity , or a floating entity (lines, curves, spiral-curve-spiral groups and spirals) to the alignment.
- Alignment Labels and Tables
Use the label and table styles to control the appearance and behavior of alignment labels and tables in a drawing.
- Editing Alignments
Edit an alignment by modifying the geometry or parameter values.
- Reversing Alignment Direction
Use this command to reverse the direction and stationing of an alignment.
- Reversing Alignment Sub-Entity Direction
Reverse the direction of a fixed, unconnected line or curve entity.
- Using AutoCAD Object Snaps with Alignment Objects
You can use AutoCAD object snaps (OSNAPs) with the alignment object. Although there are differences, alignment OSNAPs function in a manner consistent with OSNAPs to AutoCAD lines, curves, and polylines.
- Deleting Alignment Entities
Use one of several methods to delete an alignment or alignment sub-entity.
- Alignment Command Reference
You can use AutoCAD Civil 3D commands when you work with alignments. The following table lists the alignment-related AutoCAD Civil 3D commands and briefly describes their functionality.