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Drawing Tangent-Tangent Alignments

Product Documentation
Intermediate
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Use the Alignment Layout Tools to create and edit alignments.

You can use either of the following commands to create a quick layout of the alignment. The lines and curves you create are fixed entities that can be edited without losing tangency.

Tangent-Tangent No Curves

Use this command to create a quick layout of an alignment. Specify tangent points of intersection (PI). Optionally add curves later.

Tangent-Tangent With Curves

Use this command to lay out an alignment, automatically creating curves at points of intersection (PI). Curve parameters are the current values in the Curve and Spiral Settings dialog box.

Tip

You can use transparent commands when you are prompted to specify direction, radius, or length, or use station offsets to specify any points. For more information, see Transparent Commands.

Tutorial Exercise: Creating an Alignment with Spirals and Curves

To draw an alignment using the tangent-tangent method with no curves

  1. Click Home tabCreate Design panelAlignment drop-downAlignment Creation Tools.At the Command prompt, enter CreateAlignmentLayout.
  2. In the Create Alignment-Layout dialog box, enter creation information.
  3. On the Alignment Layout Tools toolbar, click Tangent-Tangent (No Curves).
  4. Specify the start point.
  5. Continue to specify points. Press Enter to end the command, or click another command from the Alignment Layout Tools toolbar.

To draw an alignment using the tangent-tangent method with curves

  1. Click Home tabCreate Design panelAlignment drop-downAlignment Creation Tools.At the Command prompt, enter CreateAlignmentLayout.
  2. In the Create Alignment-Layout dialog box, enter creation information.
  3. On the Alignment Layout Tools toolbar, click Tangent-Tangent (With Curves).
  4. Specify the start point.
  5. Continue to specify points. Press Enter to end the command or select another command from the Alignment Layout Tools.

    Curves are created to comply with the values in one of the following places:

    • If the alignment has design criteria applied to it, the minimum radius for the current design speed is applied to the curve. If no solution can be found with the minimum radius value, the curve is not drawn.
    • If the alignment does not have design criteria applied to it, the default value specified in the curve and spiral settings is applied to the curve. For more information, see Curve and Spiral Settings.

To insert a PI on a fixed line

  1. Click Alignment tabModify panelGeometry Editor.At the Command prompt, enter EditAlignment.
  2. On the Alignment Layout Tools toolbar, click Insert PI.
  3. In the drawing, pick a point near a tangent, where you want to insert the PI.

To remove a PI and combine two tangents

  1. Click Alignment tabModify panelGeometry Editor.At the Command prompt, enter EditAlignment.
  2. On the Alignment Layout Tools toolbar, click Delete PI.
  3. In the drawing, pick a point near the PI you want to delete.

To break apart the PI of an incoming or outgoing tangent endpoint

  1. Click Alignment tabModify panelGeometry Editor.At the Command prompt, enter EditAlignment.
  2. On the Alignment Layout Tools toolbar, click Break-Apart PI.
  3. In the drawing, pick a point near the PI you want to break apart.
  4. Specify the distance to split the PI by picking two points or entering a value on the command line. This value is the distance each line is shortened from the PI.
  5. Specify the second point.

Ribbon

Click Home tabCreate Design panelAlignment drop-downAlignment Creation Tools

Click Alignment tabModify panelGeometry Editor

Menu

Click Alignments menu Create Alignment By Layout

Click Alignments menu Edit Alignment Geometry

Command Line

CreateAlignmentLayout

EditAlignment

Dialog Box

Create Alignment - Layout Dialog Box

Alignment Layout Tools


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