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Integrated BIM tools, including Revit, AutoCAD, and Civil 3D
Professional CAD/CAM tools built on Inventor and AutoCAD
Draw an alignment for a road in Civil 3D using the Tangent-Tangent (no curves) tool, and then add curves individually.
Type:
Tutorial
Length:
5 min.
Transcript
00:03
Civil 3D alignments are key components in civil engineering,
00:07
guiding the design of roads, railways, and utilities.
00:12
They define the center line and geometry for transportation routes, utility layouts, and land development projects.
00:21
Alignments are essential for creating accurate 3D corridor models, performing earthwork calculations,
00:27
and designing intersections, roundabouts, and bridges.
00:32
To create an alignment in Civil 3D, begin with a drawing open and a grading object already placed.
00:40
On the Home tab, Create Design panel, expand the Alignment drop-down, and select Alignment Creation Tools.
00:48
In the Create Alignment – Layout dialog, Name field, enter an alignment name.
00:56
Here, the alignment is named after the road it will represent.
00:60
Next, expand the Type drop-down to specify the type of alignment,
01:05
which in this case, is Centerline.
01:08
From the General tab, expand the Site drop-down and specify a site.
01:14
Ensure that this is the same site as your grading object,
01:18
so that the alignment and grading object will interact with each other.
01:22
Expand the Alignment style drop-down and specify a style,
01:27
which controls the visual appearance of alignment components and labels.
01:32
Finally, in the Alignment label set drop-down,
01:35
specify a label style to apply labels along the alignment at specific points,
01:40
such as the major and minor stations or geometry points.
01:45
For this example, select all labels.
01:48
Click OK.
01:50
The Alignment Layout Tools toolbar displays,
01:53
with both freehand and constraint-based alignment creation and editing tools.
01:59
Expand the Tangent drop-down to add tangents with or without curves.
02:04
If you are adding curves, you can also select Curve and Spiral Settings
02:09
to enter the curve settings and to specify the spiral defaults.
02:14
However, in this instance, since none of the curves are consistent, they will need to be added individually.
02:21
The road also needs to stay within a pre-designated alignment right of way,
02:26
so Tangent-Tangent (No curves) is selected.
02:30
You are prompted to specify a starting point.
02:34
In this example, it is a specific point number, because it is the end point of a centerline that already exists.
02:41
From the Transparent Commands toolbar, select Point number.
02:45
Enter the point number to connect to, then press ESC to exit the transparent command.
02:52
The bearing and distance for the right of way are known,
02:55
and you want to stay within that right of way.
02:58
From the Transparent Commands toolbar, select Bearing Distance.
03:03
When prompted to select a quadrant, here, enter 2 for Southeast.
03:09
Next, type in the bearing, starting with degrees, followed by a decimal point,
03:14
and then the minutes and seconds.
03:17
Finally, enter the distance along that bearing.
03:23
Continue typing in bearing and distance values to complete the alignment,
03:29
then press ESC twice to exit the command.
03:34
Since most roads do not have sharp corners like these,
03:40
the next step is to add some curves.
03:43
From the Alignment Tools toolbar, expand the Curve drop-down.
03:48
Floating or Free Curves are recommended for smooth transitions,
03:52
because these curves stay tangent, even if you change the point of intersection.
03:56
In this case, all curves will be applied as Free Curve Fillet (Between two entities, radius),
04:03
since the radius is known.
04:05
To create a curve, select the beginning and ending entities by picking a point on each side of the intersection point.
04:12
Then, choose whether the curve is greater than or less than 180°.
04:18
Here, select Lessthan180.
04:22
Next, set the radius to 150.
04:27
When you press ENTER, the curve is applied, and notice that the command stays active,
04:33
so you can continue adding curves.
04:35
Here, one more curve is added using the radius.
04:39
However, suppose that for the next selected entity, the tangent length is known.
04:45
From the command line, click Tangent Length, and then enter a tangent length of 36.
04:53
Proceed to the next entity, continuing around the alignment.
04:58
When you are done adding curves, press ENTER.
05:01
The system will automatically label them according to the style you selected previously.
05:09
To make any modifications, select the alignment.
05:13
Since free curves were applied,
05:16
the curves will stay tangent, even if you change the alignment location.
Video transcript
00:03
Civil 3D alignments are key components in civil engineering,
00:07
guiding the design of roads, railways, and utilities.
00:12
They define the center line and geometry for transportation routes, utility layouts, and land development projects.
00:21
Alignments are essential for creating accurate 3D corridor models, performing earthwork calculations,
00:27
and designing intersections, roundabouts, and bridges.
00:32
To create an alignment in Civil 3D, begin with a drawing open and a grading object already placed.
00:40
On the Home tab, Create Design panel, expand the Alignment drop-down, and select Alignment Creation Tools.
00:48
In the Create Alignment – Layout dialog, Name field, enter an alignment name.
00:56
Here, the alignment is named after the road it will represent.
00:60
Next, expand the Type drop-down to specify the type of alignment,
01:05
which in this case, is Centerline.
01:08
From the General tab, expand the Site drop-down and specify a site.
01:14
Ensure that this is the same site as your grading object,
01:18
so that the alignment and grading object will interact with each other.
01:22
Expand the Alignment style drop-down and specify a style,
01:27
which controls the visual appearance of alignment components and labels.
01:32
Finally, in the Alignment label set drop-down,
01:35
specify a label style to apply labels along the alignment at specific points,
01:40
such as the major and minor stations or geometry points.
01:45
For this example, select all labels.
01:48
Click OK.
01:50
The Alignment Layout Tools toolbar displays,
01:53
with both freehand and constraint-based alignment creation and editing tools.
01:59
Expand the Tangent drop-down to add tangents with or without curves.
02:04
If you are adding curves, you can also select Curve and Spiral Settings
02:09
to enter the curve settings and to specify the spiral defaults.
02:14
However, in this instance, since none of the curves are consistent, they will need to be added individually.
02:21
The road also needs to stay within a pre-designated alignment right of way,
02:26
so Tangent-Tangent (No curves) is selected.
02:30
You are prompted to specify a starting point.
02:34
In this example, it is a specific point number, because it is the end point of a centerline that already exists.
02:41
From the Transparent Commands toolbar, select Point number.
02:45
Enter the point number to connect to, then press ESC to exit the transparent command.
02:52
The bearing and distance for the right of way are known,
02:55
and you want to stay within that right of way.
02:58
From the Transparent Commands toolbar, select Bearing Distance.
03:03
When prompted to select a quadrant, here, enter 2 for Southeast.
03:09
Next, type in the bearing, starting with degrees, followed by a decimal point,
03:14
and then the minutes and seconds.
03:17
Finally, enter the distance along that bearing.
03:23
Continue typing in bearing and distance values to complete the alignment,
03:29
then press ESC twice to exit the command.
03:34
Since most roads do not have sharp corners like these,
03:40
the next step is to add some curves.
03:43
From the Alignment Tools toolbar, expand the Curve drop-down.
03:48
Floating or Free Curves are recommended for smooth transitions,
03:52
because these curves stay tangent, even if you change the point of intersection.
03:56
In this case, all curves will be applied as Free Curve Fillet (Between two entities, radius),
04:03
since the radius is known.
04:05
To create a curve, select the beginning and ending entities by picking a point on each side of the intersection point.
04:12
Then, choose whether the curve is greater than or less than 180°.
04:18
Here, select Lessthan180.
04:22
Next, set the radius to 150.
04:27
When you press ENTER, the curve is applied, and notice that the command stays active,
04:33
so you can continue adding curves.
04:35
Here, one more curve is added using the radius.
04:39
However, suppose that for the next selected entity, the tangent length is known.
04:45
From the command line, click Tangent Length, and then enter a tangent length of 36.
04:53
Proceed to the next entity, continuing around the alignment.
04:58
When you are done adding curves, press ENTER.
05:01
The system will automatically label them according to the style you selected previously.
05:09
To make any modifications, select the alignment.
05:13
Since free curves were applied,
05:16
the curves will stay tangent, even if you change the alignment location.
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