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Learn how to Create Alignments from Objects and Specify Design Criteria in Autodesk Civil 3D with this step-by-step Road Design Tutorial.

In this tutorial, you will learn how to convert existing AutoCAD objects into Civil 3D Alignments and apply design criteria for accurate roadway alignment design.

Create Alignments from Objects in Civil 3D
Convert Lines, Arcs and Polylines into Alignments
Alignment Creation Settings
Specify Alignment Design Criteria
Apply Design Criteria to Road Alignments
Understand Alignment Design Checks
Civil 3D Roadway Design Workflow

This tutorial is useful for Civil Engineers, BIM Modelers, CAD Technicians, Road Designers and Civil 3D Beginners.

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Transcript
00:09The Alignments Collection or in the Sites Collection as part of a site.
00:15Alignments are routes laid out in plan only that have defined geometry and denote the linear path
00:21of a road, railway, watercourse or other linear feature we wish to design.
00:28We're going to create a centreline alignment for the existing part of McAllister Boulevard.
00:33It's displayed in the drawing as an XRF attachment of a survey drawing.
00:39On the Home ribbon, Create Design Panel, click on Alignment then Create Alignment from Objects.
00:46We use this method when we want to create alignments based on existing information
00:50that we have in a drawing. This could be from land survey information
00:54when we need to extend or redesign an existing road or it could be an architect's planning layout
01:00that we want to replicate in our design. Zoom to the survey area of McAllister Boulevard.
01:06On the command line, choose XRF and pick the red centreline of the road at the northern end
01:12through the XRF. Press Enter to accept the selection.
01:18The direction of our alignment is displayed as an arrow on the alignment.
01:22You can reverse the direction at this point if you need to by entering R on the command line.
01:29Press Enter to accept the alignment direction.
01:33In the Create Alignment dialog, enter McAllister existing for the name.
01:39The alignment type will be set to centerline. The options here will place the alignment
01:45in a separate subfolder in Prospector. We won't put this in a site. Placing an alignment in a site
01:52will allow it to subdivide any parcels that are defined in the same site.
01:58Set the alignment style to existing. The alignment style controls how the alignment entities are displayed,
02:05such as color, line type, and line weight. Choose No labels for the label set,
02:12as we don't want to display labels on this alignment.
02:17Deselect Add curves between tangents. This will prevent Civil 3D from adding curves automatically
02:24between the straight segments in our alignment. Click OK to save the alignment.
02:33We can now see the newly created alignment in Model Space and also under the alignments Centerline
02:39alignments collection in Prospector. We can use Prospector to select or zoom to the alignment,
02:46which is useful when you have a large model. You can right click on the alignment in Prospector
02:52and select Properties to see information about the alignment.
02:56In here, we can change its name and style. We can set the position of the zero station,
03:02adjust the station values, and review the alignment length. We can hide parts of the alignment using masking.
03:11Other tabs allow us to change how the alignment intersection points are displayed,
03:16change how tangents and curves are constrained, and specify design criteria.
03:22Now pan the drawing to the proposed part of McAllister Boulevard.
03:26We're going to convert the white polyline to an alignment.
03:30Go back to the Home ribbon and choose Alignment, then choose Create Alignment from Objects.
03:36In the model, pick the start of the polyline on the left.
03:40This will set Zero Station to that end of the alignment.
03:45Press Enter to accept the selection, then press Enter again to accept the alignment direction.
03:53In the Create Alignment dialog, change the name to McAllister Boulevard.
03:58You may enter a description for the alignment if you wish.
04:03Change the style to Layout.
04:06Set the label set to Major, Minor and Geometry points.
04:11This will label the alignment with dynamic labels,
04:14showing the station values and marking changes in geometry.
04:19Deselect Add Curves between Tangents.
04:22The polyline we've picked already has curves defined in it, so we don't need to add any curves.
04:28Click OK.
04:31The alignment has been created with the labels we chose added.
04:35Notice the warning symbol that indicates the first curve may not be tangential to the first tangent.
04:41This will often be the case when converting polylines with curves.
04:47We're now going to create the Sycamore Heights alignment.
04:50From the Home ribbon, click Alignments, then Create Alignments from Objects.
04:55This time we have individual AutoCAD lines, which we're going to select one by one.
05:01Be sure to pick the first tangent at the start of the line as shown.
05:06Press Enter when all of the lines have been selected.
05:10If your alignment direction is pointing in the opposite direction,
05:13then enter R on the command line to reverse the direction.
05:17Otherwise, press Enter.
05:20In the dialog, set the name to Sycamore Heights.
05:23We'll leave the other settings on their defaults.
05:28Make sure that Add Curves between Tangents is selected.
05:31We want Civil 3D to automatically place curves between our selected tangents.
05:38Set the default radius for these curves to 300 feet and click OK.
05:44Our alignment has been created with curves added between all of the tangents.
05:49Now we'll create Woodside View using the same method.
05:54Again, we have AutoCAD lines that we're going to convert.
05:59When you select the lines, pick them in turn, starting at the southern end.
06:04We want this alignment to run from south to north.
06:08If your alignment direction is north to south, then enter R on the command line to reverse the direction.
06:15Otherwise, press Enter to accept.
06:18In the Create Alignment dialog, change the name to Woodside View.
06:22Keep the other settings, but change the default curve radius to 180 feet.
06:28Click OK to save the alignment.
06:33Finally, we're going to create the center line for existing road, Sycamore Street.
06:38In the survey drawing, we have two yellow lines that represent the road edges.
06:44We'll use these two lines to find the center line of the road.
06:48From the Home ribbon, choose Alignment, then create Best Fit Alignment.
06:54A Best Fit Alignment can be created from blocks, existing lines or polylines, points,
07:01Kogo points or feature lines.
07:05Set the input type to AutoCAD entities.
07:09Civil 3D will analyze the coordinates of the inputs to determine the Best Fit Alignment through
07:14the points, adding curves and spirals as necessary.
07:18The inputs can be a single path or two paths to find a center line as in our case.
07:24Click the button for Path 1 entities and select the left-hand road edge in the drawing and press Enter.
07:32Repeat for Path 2, selecting the right-hand road edge.
07:36We need to enter some information to guide the alignment creation.
07:41Set the maximum radius for curve detection to 60,000.
07:46We're choosing a large value to ensure we get curves added and not just tangents.
07:52We often get a better result when we also allow spiral curves to be added.
07:58Set the alignment name to Sycamore Street.
08:02Change the alignment label set to Major, Minor, HMV geometry points.
08:08At the bottom of the dialog, deselect label offsets.
08:12We don't want it to add labels of the offsets to the drawing.
08:16Click OK.
08:18A report is displayed showing the centerline point list together with the offset Best Fit information
08:25at each point.
08:27You can't adjust anything in this table.
08:30It's simply providing information about the correlation of the points to the calculated alignment.
08:36The information in the report can be exported as text or copied to the clipboard for future reference.
08:45Close the report to accept the alignment.
08:48The alignment for Sycamore Street has now been added to the drawing and labelled.
08:53In this model, we have created alignments by converting AutoCAD 3D.
08:58We'll want to know that we are meeting any national or local design standards.
09:03There are two ways that we can apply checking to our design,
09:06using a design criteria file and using check sets.
09:12The design criteria file generally comes as part of a country kit that can be installed with Sybil 3D.
09:18The file is in XML format and contains tables of standards for highway design,
09:25such as formula for superelevation of the road at different design speeds,
09:29and it can prompt us to enter the correct values during design.
09:33You can edit or even create your own design criteria file.
09:38The design criteria file is typically saved on a server for the whole design team to access.
09:44We can assign a table from the design criteria file to individual alignments.
09:51Additional design criteria that might be desirable but aren't included in a design criteria file
09:56can be added as design checks.
09:59Individual design checks are grouped together as a design check set,
10:03and the check set can be applied to the alignment.
10:06Checks and check sets are saved in the drawing file and would normally be defined in our project template.
10:13In our model we have some residential roads.
10:16These are the subdivision roads, Sycamore Heights and Woodside View.
10:20And we have a road that leaks neighbourhoods.
10:23This is our collector road, McCollister Boulevard.
10:26We are going to create some design checks so that we can see whether our design choices,
10:31such as curve radii or tangent lengths, meet the standards that we are required to work to.
10:37For our subdivision roads, our tangents should be a minimum length of 100 feet,
10:42and our curves should have a minimum radius of 160 feet.
10:47For our collector roads, our tangents should be a minimum length of 300 feet,
10:52and our curves should have a minimum radius of 1200 feet.
10:56To add the design checks, in the drawing, click on the Settings tab on the Civil 3D tool space.
11:03Expand Alignment and then expand the Design Checks folder.
11:07Design checks are grouped together in a check set.
11:10Individual checks are created by their element type and then added to a check set.
11:16First, we are going to add some checks for our alignment tangents.
11:20Select the Line folder, right click and choose New.
11:24In the Design Check dialog, change the name to Subdivision Min Length 100.
11:32The name will be displayed on the warning symbol tooltip,
11:36so it's useful to name it so you know what criteria it has been checked.
11:41Click on the Insert Property button.
11:44Here you'll find relevant properties for the alignment that you can use in your checks.
11:48Choose the Length property.
11:50This will add it into the body of the expression.
11:53Click on the greater than and equal to symbol,
11:56and then type 100.
11:58This expression tells Sybil 3D that the length of the tangent line
12:02should be greater than or equal to 100, otherwise it will display a warning.
12:07Expressions can also include Visual Basic functions,
12:11which can be added using the Functions button.
12:17Click OK to save the check.
12:21Go back to the Line folder in Settings, right click and choose New.
12:27Rename this Design Check to Collector Min Length 300.
12:35From the expressions, add the Length property, then greater than or equal to, and then 300.
12:42Click OK.
12:46Now we'll add some Curve Design Checks.
12:49In the Settings tab, click on Curve, right click and choose New.
12:55Rename this Design Check to Subdivision Min Rad 160.
13:04Insert the Radius property into the expression, and then add greater than or equal to, then 160.
13:11Click OK.
13:14Add another Curve Check, this time for the Collector Road.
13:18Name it Collector Min Rad 1200.
13:26Add the Radius property, then select greater than or equal to, then 1200.
13:36Click OK.
13:38Now we'll group our Design Checks into Check Sets.
13:44In the Settings tab, click on the Design Check Sets folder, right click and choose New.
13:52In the Information tab, rename the Check Set to Subdivision.
13:58Select the Design Checks tab, and with the Type Set to Line, select the Line Check, Subdivision,
14:05Min Length 100, and click Add. This will add the Design Check to the Check Set.
14:12Change the Type to Curve, and then add the Subdivision Min Rad 160 Check.
14:18Click OK to save the Check Set.
14:23Now create a new Design Check Set.
14:26On the Information tab, change the name to Collector.
14:31In the Design Check tab, for Type Line, add the Collector Min Length 300 Check.
14:38Change the Type to Curve, and add the Collector Min Rad 1200 Check.
14:43Click OK to save the Check Set.
14:46In the model, select the alignment for the Collector Road, Macaulister Boulevard.
14:51Right click and choose Alignment Properties.
14:54Click on the Design Criteria tab.
14:56On the left side of the dialog, we have a table that shows the design speeds assigned to the alignment.
15:02A road could have multiple speeds assigned along its length,
15:06and each one can have a station value, denoting where it takes effect.
15:10The tables in the Design Criteria file, and in your own check sets,
15:15can reference the design speeds in their expressions,
15:18and apply different checking criteria for each one.
15:22This alignment currently has one that is set to 60 mph.
15:26You can add additional speeds using these buttons.
15:31Add a new Design Speed to Macaulister Boulevard.
15:35Set the station for the new Design Speed to 2300.
15:40This will be at the Approach to the Roundabout.
15:45You can also pick the station in the drawing using the button on the side of the cell.
15:50Set the new Design Speed to 25 mph.
15:55Choose Use Criteria Based Design, and also Use Design Criteria File.
16:00Use the Browse button to view the files.
16:04We'll use the Imperial 2011 Design Standards.
16:09In the default criteria, set the Minimum Radius table to Emax 4%.
16:16This table is for a maximum of 4% superelevation.
16:21Set the Transition Length table to 2 lane,
16:24and the Attainment method should be Crown Roadway.
16:27We aren't using any superelevation for our alignment at this stage,
16:31so only some of the checks from these tables will apply.
16:35Select Use Design Check Set and set the check set to Collector.
16:39Click OK.
16:42We can now see the result of the design checks as warning symbols displayed on the alignment.
16:48Hovering the cursor on the warning symbol will display a tooltip showing the design check that
16:53was violated.
16:54This warning is from the Design Criteria File,
16:57and this warning is from our Collector Design Check Set.
17:02We're now going to apply the Subdivision Check Set to the Residential Roads.
17:07Select the Alignment Sycamore Heights, right-click and choose Alignment Properties.
17:13On the Design Criteria tab, set the Road Design Speed to 25 mph.
17:20Select Use Criteria Base Design.
17:23We won't be using the Design Criteria file for these roads,
17:27so make sure that option isn't selected.
17:31Select Use Design Check Set and choose Subdivision for the check set.
17:35Click OK.
17:39Again, we have warning symbols displayed on the alignment.
17:43The curve radii on this alignment are too small and don't meet our design standard.
17:51Click OK.
17:51Use the same process to apply design checks to the Woodside View alignment.
17:57In the Alignment Properties on the Design Criteria tab,
18:00set the design speed to 25 mph.
18:05Choose Criteria Base Design and select Design Check Set and select Subdivision Check Set.
18:11Click OK.
18:14The design check violations for check sets we've applied
18:17will also be visible in the alignment grid view.

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