Like alignments, design profiles consist of straight line segments (called tangents) and the curves that connect them. The curve geometry is a bit different, but essentially you can think of a design profile as an alignment turned on its side. The process of laying out a profile is very similar to laying out an alignment, right down to the Profile Layout Tools toolbar, which bears a striking resemblance to the Alignment Layout Tools toolbar.
To create a design profile, complete the following steps:Profile Terminology
Familiarizing yourself with the following terms will be helpful as you work with design profiles:
- Tangent
- The straight-line portions of a profile.
- PVI (point of vertical intersection)
- The location where two tangents intersect.
- PVC (point of vertical curvature)
- The beginning of a vertical curve.
- PVT (point of vertical tangency)
- The end of a vertical curve.
- Parabolic curve
- A vertical curve that does not have a constant radius and follows the shape of a parabola.
- Circular curve
- A vertical curve that has a constant radius.
- Asymmetric curve
- A vertical curve that is created from two back-to-back parabolic curves.
- Crest curve
- A vertical curve at the top of a hill where the grade leading into the curve is greater than the grade leading out. The PVI is located above the curve.
- Sag curve
- A vertical curve at the bottom of a valley where the grade leading into the curve is less than the grade leading out. The PVI is located below the curve.
- Open the drawing named Design Profile.dwg located in the Chapter 07 class data folder.
- Click one of the grid lines for the Jordan Court profile view, and then click Profile Creation Tools on the contextual ribbon.
- In the Create Profile – Draw New dialog box, enter Jordan Court FGCL for the Profile Name.
- Verify that Profile Style is set to Design Profile and the Profile Label set is set to _No Labels. Click OK.
- On the Profile Layout Tools toolbar, click the small black triangle on the far left button to expand it, and then click Draw Tangents With Curves (see Figure 7.2).
Figure 7.2 Invoking the Draw Tangents With Curves command. - Right-click the Object Snap icon at the bottom of your screen. Turn on Center and Enabled and turn off the other Object Snap options.
- Click the center of the circle marked A. Then click the remaining circles in order from left to right. Press Enter after clicking the circle marked G. The newly created profile consists of a PVI at each point you clicked. Because you used the Draw Tangents With Curves command, all PVIs (except for the beginning and ending points) also include a vertical curve.
Tips :This will configure Civil 3D so that your cursor will recognize center points and lock on (snap) to them automatically.
