In this exercise, you will create an exit ramp alignment by attaching multiple alignment objects. First, offset the roadway centerline tangent 26 m south as the start of the ramp.
On the View menu, click Named Views to display the View dialog box, under Name, select 5, click Set Current, and then click OK.
On the command line, enter OFFSET, enter 26 m for the Distance, and then select the left tangent on the left side of your screen.
Select a point below the tangent for the Side to offset, and then press ENTER.
Use the following steps to add a 1280 m radius curve to the right end of the ramp.
On the Lines/Curves menu, click Attach Multiple.
Select the right end of the new offset ramp tangent.
Enter A for the Arc option, and then press ENTER to accept the default, Radius.
Enter 1280 m for the Radius, press ENTER to accept the default, Length, and then enter 206.8 m for the Length.
Use the following steps to attach a compound spiral to the curve.
Enter S for the Spiral option, and then enter C for the Compound option.
Press ENTER to accept the default, 1280 m, for the Radius.
Enter L for the Length option, and then enter 54.397 m for the Length.
Enter 250 m for the Ending radius.
Use the following steps to attach another curve to the compound spiral.
Enter A for the Arc option, press ENTER to accept the default, Radius, and then press ENTER to accept the default, 250 m, for the Radius.
Press ENTER to accept the default, Length, and then enter 106.304 m for the Length.
Use the following steps to attach a spiral to the curve.
Enter S for the Spiral option, and then enter O for the Outcurve option.
Press ENTER to accept the default, 250 m, for the Radius, enter A for the A factor option, and then enter 146.615 for the A factor.
Use the following steps to finish the ramp alignment by drawing a tangent segment.
Enter T for the Tangent option, and then enter 206.016 m for the Length.
Press ENTER to end the command.
The ramp alignment is represented by multiple alignment objects.
Click here to see an illustration of the ramp alignment.
Take a look at all of the alignment objects in the drawing.
On the View menu, click Named Views to display the View dialog box, under Name, select 1, click Set Current, and then click OK.
This concludes the object drawing lesson. In the next lesson, you'll learn about defining and editing alignments.