Editing Alignments Using the Alignment Layout Tools

Grips are wonderful tools to edit geometry that is already there, but what if you need to add a PI or draw a curve? For that, you need the Alignment Layout Tools toolbar (see Figure 5.10). This toolbar is the same one that you used initially to lay out the alignment.

Figure 5.10  Alignment Layout Tools toolbar.

A Note about Units

Throughout this section, you’ll notice that two values are provided for units of measurement. The first value is provided for the imperial system that is used in the United States, and the second value, in parentheses, is provided for the metric system that is used in many other countries. These values most often represent imperial feet and metric meters. It is important to note that, generally, only the numeric values are entered in the software, not terms like feet or meters. Also, you should know that the two numbers provided are not necessarily equal. In most cases, they are similar values that are rounded to work efficiently in their respective measurement systems.

To edit an alignment using the Alignment Layout Tools, follow these steps:

1. Open the drawing named Editing Tools.dwg located in the Chapter 05 class data folder.

2. Click the Jordan Court alignment, and then click Geometry Editor on the ribbon. This opens the Alignment Layout Tools toolbar.

3. On the Alignment Layout Tools toolbar, click Insert PI. Then snap to the center of the circle marked A.

4. Click Delete Sub-entity, and then click the curve at the PI marked B.
5. Click the tangent between A and B to remove it as well. The alignment should now look like Figure 5.11.

   Figure 5.11  Alignment after removing tangent and curve.


6. Expand the curve button, and click More Floating CurvesFloating Curve (From Entity End, Radius, Length).
7. Click the tangent near point A.
8. Type O and press Enter to indicate a counterclockwise direction.
9. Enter a radius of 100 (30).
10. Enter a curve length of 100 (30). A short curve is placed at the end of the tangent.

11. On the Alignment Layout Tools toolbar, expand the curves button, and select Free Curve Fillet (Between Two Entities, Radius).
12. Click the curve you just created in the previous steps.
13. Click the red tangent that begins at point B.
14. Press Enter to indicate that the solution is less than 180 degrees.
15. Press R, and then Enter to indicate that it is a reverse curve.
16. Enter 100 (30) for the radius, and then press Enter to end the command.The new curve is created in the drawing, as shown in Figure 5.12.

    Figure 5.12  Alignment after addition of reverse curve.

Editing Alignments

• Editing Alignments with Grips
• Editing Alignments Using the Alignment Layout Tools
• Editing Alignments Numerically

Download Exercise File :

• Editing Alignments - Metric     --- ( 2.44 MB )
• Editing Alignments - Imperial  --- ( 2.18 MB )