This tutorial demonstrates how to create and edit layout profiles, which are often called design profiles or finished grade profiles.
A layout profile represents a proposal for a road or other designed surface. This type of profile is always drawn on the grid of a profile view, which usually displays the surface profile along the same horizontal alignment.
A layout profile includes the following elements:
- Straight line tangents with specified grade or slope.
- Points of vertical intersection (PVI) where tangents meet.
- Vertical curves that are usually parabolic in shape. Vertical curves can also be circular or asymmetrical parabolic.
Vertical curves can be one of two basic types: crest curves or sag curves.
- A crest curve exists at a hilltop, or wherever the incoming tangent has a higher grade than the outgoing tangent. There are three types of crest curves: a positive to negative grade transition, positive to positive, and negative to negative. The point of vertical intersection (PVI) of a crest curve is above the curve.
- A sag curve exists at the bottom of a valley, or wherever the incoming tangent has a lower grade than the outgoing tangent. There are three types of sag curves: a negative to positive grade transition, negative to negative, and positive to positive. The PVI of a sag curve is below the curve.
The vertical curves on a layout profile can be designed in relation to engineering speed tables for safe vehicular travel at a particular maximum speed. Other tables can be used to design vertical curves so that the distance illuminated by the headlights of a vehicle at night is always greater than the stopping distance at the maximum design speed.
For more information, see the AutoCAD Civil 3D Help topics Creating Layout Profiles and Vertical Curve Design.
Topics in this section
- Exercise 1: Creating a Layout Profile
In this exercise, you will create the layout profile. Typically, this profile is used to show the elevations along a proposed road surface or a finished grade.
- Exercise 2: Editing a Layout Profile
In this exercise, you will modify the layout profile by using grips and entering specific attribute values.
- Exercise 3: Copying a Profile and Offsetting it Vertically
In this exercise, you will copy part of a centerline layout profile. You will use the copy to create a starting line for a ditch profile that is a specified distance below the centerline.