Alignment basics

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Project index for location by station and offset.

Basis for design of corridors.

Targets for corridor design.

Basis for profiles, profile views, and sample lines.

Folder and object naming

In FDM 15-5-3 Att. 3.4 the folder location and the file naming is spelled out, with multiple examples.

Alignments will be created and saved with any related profiles. Multiple alignment/profile combinations can be stored in a single file or split up. In general, fewer files are better unless there is a need (such as multi-user editing) to have multiple files. These will be data shortcut referenced so they can be shared among project files.

Offset alignments, and their profiles, must be in the same file as the parent alignment.

Sites in relation to alignments

Sites are a control mechanism that allow objects to interact. These objects include parcels, grading elements and possibly alignments. Alignments are an option in the site control since they usually do not need the sort of interaction that is required, and can sometimes become a problem with other objects in the file. It is best to make sure the alignments you create are set to "No site" so that accidental interaction does not occur. Places where alignment interaction with objects is preferred would be with parcels, and will be discussed in detail there.

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There are five types of alignments that can be created. Generally, users should only be concerned with two of those types, centerlines and rail, outlined below:

• Centerlines: Despite its name, centerline type alignments are not always centerlines of a design. These are alignments created by a user, and is the predominant type for designs. These can be used for design start locations, as well as targeting for design definitions (edge of travel ways, shoulder slope breaks, etc.) Centerline alignments can have superelevation assigned to them.
• Rail: If you are creating rail design this type understands the Cant functionality, and will build with specific rail needs in mind. You should not use rail alignment types in other designs.
• Offset: This type of alignment creates a child alignment that is geometrically tied to a parent alignment. This type is used for creating tapers and geometry parallel to centerline alignments.
• Curb Return: This type of alignment is built by the intersection tool to create curb return horizontal geometry. The user would not create a curb return alignment manually, and an alignment should never have the type changed to this after it is created. In the case this switch is made it has prevented other functionality from working.
• Miscellaneous: The alignment type is created from pipe networks. The user should not change an alignment to the miscellaneous type, and there is no acceptable way to create a miscellaneous type alignment manually.

Offset Alignments

This type of alignment creates a child alignment that is geometrically tied to a parent alignment. This will allow generally parallel design that moves to stay a defined offset from the parent alignment. This type does allow for widening while maintaining the geometric tie to the parent alignment. This type is created with specific creation commands, and you should not change an alignment you are creating to an offset type manually. In the case this switch is made it has prevented other functionality from working. If you need to create an offset alignment , select the parent alignment and choose Create Offset to create the geometric connection.

Superelevation assignments in alignments

While creating corridor designs that utilize superelevation to transition subassembly slope over long distances, the data needed to accomplish this will be stored in the alignment. This alignment data will then work with properly attached subassemblies to create the needed slopes and transitions.