The plan shows where the road goes. The profile shows how it rises and falls: where it sits on fill, where it cuts, how steep each grade is. It is the drawing a checker opens first after the plan.
This article briefly explains what a profile is, then builds a Civil 3D profile in five steps. They are: sample the existing ground from the surface, create the profile view, draw the design grade with vertical curves, then put the design elevations into the data bands. The alignment is the 461 m route from Civil 3D alignment design.
What is a road profile
A profile is a vertical section along the centerline, unrolled flat. The horizontal axis is station, the vertical axis is elevation. Because the route is far longer than its relief, the vertical axis is usually exaggerated ten times so grades are visible.
| No. | Item | Meaning |
|---|---|---|
| 1 | Existing ground line | Current ground elevations along the centerline, sampled from the terrain surface |
| 2 | Design profile | The finished centerline grade. Civil 3D draws it blue in the default style; Vietnamese practice calls it the red line |
| 3 | Vertical curve labels | Station, elevation, K value and length of each curve |
| 4 | Data bands | Two rows of elevations, existing and design, at each station |
| 5 | Stations | Distance from the start of the alignment |
Where the design line is above the ground the road is on fill, below it is in cut. Where the two lines cross there is neither.
The design profile is a series of straight grades meeting at PVIs. At each PVI a vertical curve smooths the change of grade. Going from a smaller to a steeper grade gives a sag curve; from steeper to smaller, a crest curve.
Preparation: alignment and terrain surface
A Civil 3D profile always belongs to an alignment and takes its elevations from a surface. You need both in the drawing:
- A terrain surface: see contour lines, with downloadable sample data.
- An alignment: see Civil 3D alignment design.
The whole surface, alignment, profile chain makes up the first sessions of the Institute's online Civil 3D course.
Step 1: Sample the existing ground from the surface
Select the alignment. A contextual tab named after it appears. In the Launch Pad panel, click Surface Profile.
| No. | Item | Meaning |
|---|---|---|
| 1 | Alignment: TUYEN CHINH tab | Contextual tab, visible only while the alignment is selected |
| 2 | Surface Profile | Opens Create Profile from Surface |
| No. | Item | Meaning |
|---|---|---|
| 1 | Alignment | The alignment to profile. Stations 0+000.00 to 0+461.01 m fill in automatically |
| 2 | Select surfaces | Surfaces providing elevations. Several can be sampled at once, e.g. existing ground and a stripped-topsoil surface |
| 3 | Add>> | Adds the selected surface's profile to the list |
| 4 | Profile list | The new profile. Update Mode reads Dynamic: edit the surface and the profile follows |
| 5 | Draw in profile view | Go on to create the profile view |
The sample existing ground profile has more than a hundred vertices. Each is where the centerline crosses an edge of a TIN triangle.
Step 2: Create the profile view
Click Draw in profile view and the Create Profile View wizard opens, with seven pages on the left. The two worth checking are Profile View Height and Data Bands.
| No. | Item | Meaning |
|---|---|---|
| 1 | Automatic | The view spans 18.91 m to 32.81 m, the lowest and highest ground along the route. Choose User specified to fix it, e.g. to give several profiles the same datum |
| No. | Item | Meaning |
|---|---|---|
| 1 | Data Bands | The band settings page |
| 2 | Select band set | EG-FG Elevations and Stations: existing ground (EG), finished grade (FG) and stations |
| 3 | Profile1, Profile2 | The profiles feeding the two elevation rows. With no design yet, both point to existing ground |
Click Create Profile View, then pick an empty point in the drawing to place it, preferably clear of the plan.
Step 3: Set up the design profile
On the Home tab, Create Design panel, click the arrow next to Profile.
| No. | Item | Meaning |
|---|---|---|
| 1 | Create Surface Profile | Same command as Surface Profile in step 1 |
| 2 | Profile Creation Tools | Draws the design profile. Run it, then pick the profile view |
| No. | Item | Meaning |
|---|---|---|
| 1 | Name | Design profile name, e.g. DUONG DO THIET KE |
| 2 | Profile style | Design Profile, the style for design lines |
| 3 | Profile label set | Complete Label Set labels grades, PVIs and vertical curve data |
| 4 | OK | Opens the Profile Layout Tools toolbar |
Step 4: Draw the design grade with vertical curves
On the Profile Layout Tools toolbar, click the arrow next to the first button.
| No. | Item | Meaning |
|---|---|---|
| 1 | Draw Tangents With Curves | Draws grades and inserts a vertical curve at each PVI |
| 2 | Curve Settings... | Sets vertical curve type and length. Do this first |
| No. | Item | Meaning |
|---|---|---|
| 1 | Select curve type | Parabolic, the usual vertical curve |
| 2 | Crest curves | Set by Length or K value |
| 3 | Sag curves | Set by Length or K value |
The default length is 150 m. The sample grades are only 130–200 m long, so both are set to 50 m.
Choose Draw Tangents With Curves and pick the PVIs in turn. Clicking in the view is fastest; typing coordinates on the command line gives round numbers. The sample uses four points:
| Point | Station | Elevation | Grade after |
|---|---|---|---|
| Start | 0+000 | 19.50 m | 3.00% |
| PVI 1 | 0+200 | 25.50 m | 3.46% |
| PVI 2 | 0+330 | 30.00 m | 0.23% |
| End | 0+461 | 30.30 m |
| No. | Item | Meaning |
|---|---|---|
| 1 | Design line in progress | Dashed blue line through the points entered so far |
| 2 | Command line | The typed points, and the prompt for the next one |
Press Enter after the last point. Civil 3D inserts a sag curve at PVI 0+200 and a crest curve at PVI 0+330, with full labels.
Step 5: Put the design elevations into the data bands
The bands still show existing ground on both rows, because the view was created before the design existed. Select the profile view, click Profile View Properties, go to the Bands tab and scroll right to the Profile2 column.
| No. | Item | Meaning |
|---|---|---|
| 1 | Bands tab | The view's data bands |
| 2 | Profile2 | Choose DUONG DO THIET KE. The second row then shows design elevations |
Click OK. The bands now carry both elevation rows, and the vertical curve labels give each curve's data.
| No. | Item | Meaning |
|---|---|---|
| 1 | Sag curve at PVI 0+200 | 50 m long, K = 108.33, low point at 24.75 m |
| 2 | Crest curve at PVI 0+330 | 50 m long, K = 15.47, high point at 30.06 m |
| 3 | Data bands | Two numbers per station: existing on top, design below |
The bands give a first feel for quantities. At station 0+160 existing ground is 22.80 m and design 24.30 m, a 1.5 m fill. Around 0+350 the ground rises to nearly 32.8 m while the design sits near 30.05 m, a cut of almost 2.8 m.
Common mistakes with Civil 3D profiles
Typed points land in the wrong place. With the cursor inside the drawing, typed numbers go through Dynamic Input. From the second point on, it reads them as relative coordinates, so points fly out of the view. Move the cursor out of the drawing while typing, or prefix the coordinates with # in Dynamic Input.
Vertical curves will not insert. The 150 m default is longer than the grades. Lower it in Curve Settings before drawing.
Both band rows are identical. Profile2 still points to existing ground. Change it on the Bands tab as in step 5.
Stations labelled like 1+75.00. The default vertical curve label writes stations in 100 m stations, so 1+75.00 is 175 m, not 1,075 m. Edit that label style for consistent km+m notation.
The alignment changed but the profile did not. An existing-ground profile updates only if its Update Mode is Dynamic. Check it in Profile Properties.
Frequently asked questions
How does a profile differ from a cross section?
A profile runs along the centerline and shows elevations and grades from start to end. A cross section cuts across the centerline at a station and shows the road shape and side slopes there.
Why is the design profile blue in Civil 3D?
The Design Profile style sets the colour. Change it in the profile style, or reassign the layer, if your drawings require red.
How do I edit the design profile afterwards?
Select it and drag PVI grips to change station and elevation, or reopen Profile Layout Tools to insert or delete PVIs. Labels and bands follow.
What vertical exaggeration should I use?
The default profile view style exaggerates ten times. Change it in the profile view style, Graph tab, if you need another ratio.
Related articles
The profile is the third link after contour lines and Civil 3D alignment design. Autodesk's own instructions are on creating a surface profile along an alignment.
Learn the full path from profiles to cross sections, corridors and earthwork in the Institute's online Civil 3D course.