Chapter 8

Assemblies and Subassemblies

Roads, ditches, trenches, and berms usually follow a predictable pattern known as a typical section. Assemblies are how you tell the AutoCAD^® Civil 3D^® software what these typical sections look like. Assemblies are made up of smaller components called subassemblies. For example, a typical road section assembly contains subassemblies such as lanes, sidewalks, and curbs.

In this chapter, the focus will be on understanding where these assemblies come from and how to build and manage them.

In this chapter, you will learn to:

• Create a typical road assembly with lanes, curbs, gutters, and sidewalks
• Edit an assembly
• Add daylighting to a typical road assembly

Subassemblies

A subassembly is a building block of a typical section, known as an assembly. Examples of subassemblies include lanes, curbs, sidewalks, channels, trenches, daylighting, and any other component required to complete a typical corridor section.

An extensive catalog of subassemblies has been created for use in Civil 3D. More than a hundred subassemblies are available in the standard catalogs, and each subassembly has a list of adjustable parameters. There are also about a dozen generic links you can use to further refine your most complex assembly needs. From ponds and berms to swales and roads, the design possibilities are almost infinite.

The Tool Palettes

You will add subassemblies to a design by clicking on them from the subassembly tool palette, as you'll see later in this chapter. By default, Civil 3D has several tool palettes created for corridor modeling.

You can access these tool palettes from the Home tab and clicking the Tool Palettes button on the Palettes panel or by pressing Ctrl+3.

When Civil 3D is installed, you have an initial set of the most commonly used assemblies and subassemblies ready to go. The Tool Palettes window consists of multiple customizable tabs that run down the right side. These tabs categorize the assemblies and subassemblies so that they are easy to find and organize.

The top default tab in the Tool Palettes window is the Assemblies tab. On this tab you will find a selection of predefined, completed assemblies (Figure 8.1). These are a great starting point for beginners who are looking for examples of how subassemblies are put together into an assembly. There are examples of simple roadway sections as well as more advanced items, such as intersection and roundabout examples. To use one, click on the desired assembly, and then click to place it in your drawing and press to end the command.

Figure 8.1 Tool Palettes predefined assemblies

The Corridor Modeling Catalog

If the default set of subassemblies in the Tool Palettes window are not adequate for your design situation, check the Corridor Modeling Catalog for one that will work.

The Corridor Modeling Catalog is installed by default on your local hard drive. On the Home tab, expand the Palettes panel and click the Content Browser button to open a content browser interface.

Choose either the Metric or Imperial catalog to explore the entire collection of subassemblies available in each category (see Figure 8.2).

Figure 8.2 The front page of the Corridor Modeling Catalog

Adding Subassemblies to a Tool Palette

If you'd like to add additional subassemblies to your Tool Palettes window, you can use the i-drop to grab subassemblies from the catalog and drop them onto the Tool Palettes window. To use the i-drop:

Figure 8.3 Using the i-drop to add the RailSingle subassembly to a tool palette

Building Assemblies

You build an assembly from the Home tab ⇒ Create Design panel by choosing Assembly ⇒ Create Assembly. The result is the main assembly baseline marker. This is the point on the assembly that gets attached to your design alignment and profile. A typical assembly baseline is shown in Figure 8.4.

Figure 8.4 Creating an assembly (left); an assembly baseline marker (right)

When an assembly is created, you have the option of telling Civil 3D what type of assembly this will be:

• Undivided Crowned Road
• Undivided Planar Road
• Divided Crowned Road
• Divided Planar Road
• Railway
• Other

These categories will help the software determine the axis of rotation options in superelevation, if needed.

Once an assembly is created and assigned a type, you start piecing it together using various subassemblies to meet your design intent. In the next section we will look at how you can create the most common assembly type, an undivided crowned road.

Creating a Typical Road Assembly

The process for building an assembly requires the use of the Tool Palettes window (accessible using Ctrl+3) and the AutoCAD Properties palette (accessible using Ctrl+1), both of which can be docked. You'll quickly learn how to best orient these palettes with your limited screen real estate. If you run dual monitors, you may find it useful to place both of these palettes on your second monitor.

The exercise that follows builds a typical assembly, as shown in Figure 8.5, using LaneSuperelevationAOR, UrbanCurbGutterGeneral, UrbanSidewalk, and DaylightMaxOffset subassemblies.

Figure 8.5 A typical road assembly

Let's have a more detailed look at each component you'll use in the following exercise. A quick peek into the subassembly help file will give you a breakdown of attachment options; input parameters; target parameters; output parameters; behavior; layout mode operation; and the point, link, and shape codes.

The LaneSuperelevationAOR Subassembly

The LaneSuperelevationAOR subassembly is the best all-purpose subassembly for lanes. It can superelevate for an inside or outside lane if needed, and allows for up to four layers of materials. The input parameters available are Side, Width, Default Slope, Pave1 Depth, Pave2 Depth, Base Depth, Subbase Depth, Use Superelevation, Slope Direction, Potential Pivot, Inside Point Code, and Outside Point Code. The default width of 12′ (3.6 m) can be adjusted in the parameters or can be used with an offset alignment to control its width. Figure 8.6 shows the image provided in the subassembly help file for this subassembly.

Figure 8.6 The Lane SuperelevationAOR subassembly help diagram

The UrbanCurbGutterGeneral Subassembly

The UrbanCurbGutterGeneral subassembly is another standard component that creates an attached curb and gutter. Looking into the subassembly help file, you'll see a diagram of UrbanCurbGutterGeneral with input parameters for Side, Insertion Point, Gutter Slope Method, Gutter Slope, Gutter Slope Direction, Subbase Depth, Subbase Extension, Subbase Slope Method, Subbase %Slope, and the subassembly's seven dimensions. You can adjust these parameters to match many standard curb-and-gutter configurations. Figure 8.7 shows the image provided in the subassembly help file for this subassembly.

Figure 8.7 The UrbanCurb GutterGeneral subassembly help diagram

The UrbanSidewalk Subassembly

The UrbanSidewalk subassembly creates a sidewalk and terrace buffer strips. The help file lists the following six input parameters for the UrbanSidewalk subassembly: Side, Inside Boulevard Width, Sidewalk Width, Outside Boulevard Width, %Slope, and Depth. These input parameters let you adjust the sidewalk width, material depth, and buffer widths to match your design specification. Figure 8.8 shows the image provided in the subassembly help file for this subassembly.

Figure 8.8 The UrbanSidewalk subassembly help diagram

The UrbanSidewalk subassembly can return quantities of concrete (or other sidewalk construction material), but not gravel bedding or other advanced material layers.

The DaylightMaxOffset Subassembly

The DaylightMaxOffset subassembly is a nice “starter” for creating simple, single-slope daylight instructions for your corridor. In Civil 3D, an offset dimension is measured from the baseline, and a width is measured from the attachment point. Therefore, the maximum offset in our example is measured from the centerline of the road, which is the baseline. The slope will attempt a default of 4:1, but it will adjust if it needs to in order to keep inside your specified maximum offset (such as a right-of-way line). Options are also available for rounding. Figure 8.9 shows the image provided in the subassembly help file for this subassembly.

Figure 8.9 The DaylightMax Offset subassembly help diagram for the cut scenario

In the following exercise, you'll build a typical road assembly using these subassemblies. Follow these steps:

1. Start a new blank drawing from the _AutoCAD Civil 3D (Imperial) NCS template that ships with Civil 3D. For metric users, use the _AutoCAD Civil 3D (Metric) NCS template.

2. Confirm that your Tool Palettes window is showing the subassembly set appropriate for your drawing units (or you may end up with monster 12 meter lanes!).

If you need to change your active Tool Palettes window from metric to Imperial or vice versa, right-click the Tool Palettes control bar located at the top of the window, as shown in Figure 8.10.

Figure 8.10 Right-click the Tool Palettes control bar to change assembly sets if needed.

3. Verify that your drawing scale is set to 1≤=10′ (1:50 for metric users).

4. From the Home tab ⇒ Create Design panel choose Assembly ⇒ Create Assembly.

The Create Assembly dialog opens.

5. Enter Urban 14′ Single-Lane (or Urban 4.5m Single-Lane) in the Name text box.

6. Set Assembly Type to Undivided Crowned Road.

7. Confirm that Assembly Style is set to Basic and Code Set Style is set to All Codes, and click OK.

8. Pick a location in your drawing for the assembly; somewhere in the center of your screen is fine to place your red assembly baseline marker.

9. Locate the Lanes tab on the Tool Palettes window, and position the palette on your screen so that you can clearly see the assembly baseline.

10. Click the LaneSuperelevationAOR button on the Tool Palettes window.

The AutoCAD Properties palette appears.

11. Locate the Advanced Parameters section on the Design tab of the AutoCAD Properties palette (Figure 8.11).

Figure 8.11 Advanced Parameters on the Properties palette

This section lists the LaneSuperelevationAOR parameters.

12. Change the Width parameter to 14′ (4.5 m).

Your Properties palette should resemble Figure 8.11.

13. At the Select marker point within assembly or [Insert Replace Detached]: prompt, select anywhere on the red assembly baseline marker to place the first lane.

Note that it is placed on the right side as you had specified in the Advanced Parameters section.

14. Before ending the command, click the red assembly baseline marker again to place the left lane.

Civil 3D 2013 now has the intelligence to autodetect the side and places a left lane even though you did not change the side specified in the Advanced Parameters.

15. Press to end the command.

16. Switch to the Curbs tab in the Tool Palettes window.

17. Click the UrbanCurbGutterGeneral button on the Tool Palettes window.

The AutoCAD Properties palette appears.

18. You will accept the parameter defaults, so no changes are needed. Remember that the Side parameter will automatically be detected so there is no need to change it.

19. At the Select marker point within assembly or [Insert Replace Detached]: prompt, select the circular marker located at the top right of the right LaneSuperelevationAOR subassembly.

This marker represents the top-right edge of pavement (see Figure 8.12).

Figure 8.12 The UrbanCurb- GutterGeneral subassembly placed on the Lane SuperelevationAOR subassembly

20. Press to end the command.

You will add the left curb later. Keep this drawing open for the next portion of the exercise.

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If You Goof…

Often, the first instinct when a subassembly is misplaced is to Undo or erase the wayward piece. However, if you have spent a lot of time diligently tweaking parameters, there is a way to fix things without redoing the subassembly.

Moving a Subassembly

Select the errant subassembly component and use the Move option from the contextual tab ⇒ Modify Subassembly panel. Use this instead of the base AutoCAD Move tool to get the best results. Using regular AutoCAD Move may cause unexpected results in the corridor.

Inserting a Subassembly

Sometimes you forget to place a subassembly component, or your design changes and you want to include a subassembly that wasn't there before. In previous versions of Civil 3D, you had to delete the subassembly components from the outside in until you got to where you wanted to insert your missing subassembly and then had to re-create the deleted subassembly pieces.

In the latest version of Civil 3D, you may have noticed that every time you place an assembly the command line states Select marker point within assembly or [Insert Replace Detached]:. If you enter I, the command line will state Select the subassembly to insert after or [Before]:. This new ability to insert a subassembly will come in useful when the planner decides to add a sidewalk at the shoulder of your road.

Replacing a Subassembly

Similar to the insert operation, you can also replace a subassembly component with another component. Again, you will find this infinitely helpful when the planner decides to make changes to your design.

Deleting a Subassembly

To delete a subassembly component, you can simply select the subassembly component and press the Delete key. The assembly will connect the subassemblies on either side at the connection points previously used with the deleted component.

Changing Subassembly Parameters

If you placed everything correctly but forgot to change a parameter or two, there's an easy fix for that, too. Cancel out of any active subassembly placement and select the subassembly you wish to change. Most subassembly parameters can be changed from the AutoCAD Properties palette. For more heavy-duty modifications (such as specifying the side), you will want to get into the Subassembly Properties discussed later in this chapter.

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21. In the Curbs tab, click the UrbanSidewalk button on the Tool Palettes window.

22. In the Advanced section of the Design tab on the AutoCAD Properties palette, change the following parameters, leaving all other parameters at their default values:

Sidewalk Width: 5′ (1.5 m)

Inside Boulevard Width: 2′ (0.7 m)

Outside Boulevard Width: 2′ (0.7 m)

It may be hard to ignore the Side parameter, but setting it is not required with Civil 3D side autodetection.

23. At the Select marker point within assembly or [Insert Replace Detached]: prompt, select the circular marker on the UrbanCurbGutterGeneral subassembly that represents the top rear of the curb to attach the UrbanSidewalk subassembly (see Figure 8.13).

Figure 8.13 The BasicSidewalk subassembly placed on the UrbanCurb- GutterGeneral subassembly

24. Switch to the Daylight tab on the subassemblies Tool Palettes window, and select the DaylightMaxOffset subassembly.

25. In the Advanced Parameters area, change Max Offset From Baseline to 50′ (17 m), leaving all other parameters at their default values.

26. At the Select marker point within assembly or [Insert Replace Detached]: prompt, select the circular marker on the outermost point of the sidewalk subassembly.

Your drawing should now resemble Figure 8.14.

Figure 8.14 The complete right side of the assembly with DaylightMaxOffset

To complete the left side, you will use the Mirror Subassemblies command.

27. Select the curb, sidewalk, and daylight subassemblies on the right side of the baseline.

The Subassembly contextual tab will show a variety of tools, including Mirror (Figure 8.15).

Figure 8.15 The Subassembly contextual tab with subassembly modification tools

28. From the Subassembly contextual tab ⇒ Modify Subassembly panel choose Mirror, and then click the circular point marker located at the top left of the left LaneSuperelevationAOR subassembly.

29. Your assembly should now resemble Figure 8.5 from earlier in the chapter.

You have now completed a typical road assembly.

You may keep this drawing open to continue on to the next exercise, or use the saved copy of this drawing available from the book's web page (TypicalRoadAssembly_FINISHED.dwg or TypicalRoadAssembly_METRIC_FINISHED.dwg).

Subassembly Components

A subassembly is made up of three basic parts: links, marker points, and shapes, as shown in Figure 8.16. Each piece plays a role in your design and is used for different purposes at each stage of the design process.

Figure 8.16 Schematic showing parts of a subassembly

Links

Links are the linear components to your assembly. A link usually represents the top or bottom of a material but can also be used as a spacer between subassemblies.

Links can have codes assigned to them that Civil 3D uses to build the design. Think of these codes as nicknames. In the example assembly you created in the previous exercise, each of the subassembly components contained numerous coded links. As shown in Figure 8.17, on the sidewalk the topmost link has the codes Top and Sidewalk and on the lane subassembly the topmost codes are Top and Pave.

Figure 8.17 Link codes on the UrbanSidewalk subassembly (top) and link codes on the Lane- SuperelevationAOR subassembly (bottom)

Coded links will be your primary source of data when creating proposed surfaces from your corridors.

Marker Points

Marker points are located at the endpoints of every link and usually are represented by the circles you see on the subassemblies, as shown in Figure 8.18. As you experienced in the previous exercise, the markers are used in assembly creation to “click” subassemblies together and will also “hook” to attach to alignments and/or profiles, known as targets.

Figure 8.18 Point codes on the UrbanSidewalk subassembly (top) and point codes on the Lane- SuperelevationAOR subassembly (bottom)

Coded markers are the starting point for feature lines generated by the corridor, which are used for a variety of purposes that we will discuss in the upcoming chapters.

Shapes

Shapes are the areas inside a closed formation of links. For example, Figure 8.19 shows different subassemblies with shape codes labeled. Shapes are used in end-area material quantity calculations. At the time an assembly is created, you do not need to consider what material these shapes represent. After your corridor is complete, you will specify what materials the codes represent upon computing materials.

Figure 8.19 Shape codes on the UrbanSidewalk subassembly (top) and shape codes on the Lane- SuperelevationAOR subassembly (bottom)

Jumping into Help

Each subassembly is capable of accomplishing different tasks in your design. There is no way to tell just by looking at the icon all the acrobatics that an assembly can do. For a detailed rundown of each parameter, and what can be done with a subassembly, you will need to pop into the help files.

Subassembly Help is extremely — well, helpful! There are many doors into the help files, including from the Corridor Modeling Catalog as you saw earlier. Another way to access the help files is to right-click on any subassembly in the tool palette and select Help, as shown in Figure 8.20.

Figure 8.20 Getting to the subassembly help file for UrbanCurb- GutterGeneral

Attachment and Input Parameters

When you access Subassembly Help, it will take you to the help file specific to the subassembly you are working with. At the top, you will see a diagram showing the location of the numeric parameters that can be edited in the Properties palette, as shown in Figure 8.21.

Figure 8.21 The top portion of Subassembly Help shown with subassembly parameters

For most subassemblies, the default attachment point will be the topmost-inside marker point. The help file will tell you if this differs for the subassembly you are looking at. Scroll further down to see detailed explanation of each input parameter.

Target Parameters

Target parameters are a listing of what attachments can be set for a subassembly. There are three types of targets: a target surface, a target elevation, and a target offset. The help file will also tell you whether the target is optional or required. We will look at target parameters and setting targets in Chapter 10, “Basic Corridors.”

Output Parameters

Output parameters are values calculated on corridor build, such as the cross-slope of a lane. In several subassemblies, there is an advanced option called Parameter Reference that can use an output parameter from a previous subassembly in the assembly instead of using the value entered in the subassembly properties. We will discuss this concept further in Chapter 9, “Custom Subassemblies.”

Reading a Coding Diagram

The coding diagram gives you a list of all the codes used on the subassembly you are working with. Every coded point, link, and shape is listed here. Not all subassembly components have explicit names, such as L9 shown in Figure 8.22. If the point, shape, or link is not included in the table, it is considered uncoded.

Figure 8.22 Coding diagram and name table for UrbanCurb- GutterGeneral

Commonly Used Subassemblies

Once you gain some skills in building assemblies, you can explore the Corridor Modeling Catalog to find subassemblies that have more advanced parameters so that you can get more out of your corridor model. For example, if you must produce detailed schedules of road materials such as asphalt, coarse gravel, fine gravel, subgrade material, and so on, the catalog includes lane subassemblies that allow you to specify those thicknesses for automatic volume reports.

The following section includes some examples of different components you can use in a typical road assembly. Many more alternatives are available in the Corridor Modeling Catalog. The help file provides a complete breakdown of each subassembly in the catalog; you'll find this useful as you search for your perfect subassembly.

Each of these subassemblies can be added to an assembly using the same process specified in the first exercise in this chapter. Choose your alternative subassembly instead of the basic parts specified in the exercise, and adjust the parameters accordingly.

Common Lane Subassemblies

The LaneSuperelevationAOR subassembly is suitable for many roads, including undivided roads as shown in the previous example, and divided roads as shown in Figure 8.23. However, you may need different road lanes for your locality or design situation:

Figure 8.23 Use of Lane- SuperelevationAOR in a divided highway

LaneParabolic

The LaneParabolic subassembly (Figure 8.24) is used for road sections that require a parabolic lane in contrast to the linear grade of LaneSuperelevationAOR. The LaneParabolic subassembly also adds options for four material depths. This is useful in jurisdictions that require two lifts of asphalt, base material, and sub-base material; taking advantage of these additional parameters gives you an opportunity to build corridor models that can return more detailed quantity takeoffs and volume calculations.

Figure 8.24 The LaneParabolic subassembly help diagram

Note that the LaneParabolic subassembly doesn't have a Side parameter. The parabolic nature of the component results in a single attachment point that would typically be the assembly centerline marker.

LaneBrokenBack

For designs that call for two lanes, and those lanes must each have a unique slope, the LaneBrokenBack subassembly (Figure 8.25) can be used. This subassembly provides parameters to change the road-crown location and specify the width and slope for each lane. Like LaneParabolic, the LaneBrokenBack subassembly provides parameters for additional material thicknesses.

Figure 8.25 The LaneBrokenBack subassembly and parameters

The LaneBrokenBack subassembly, like LaneSuperelevationAOR, allows for the use of target alignments and profiles to guide the subassembly horizontally and/or vertically for both of the lanes.

Common Shoulder and Curb Subassemblies

There are many types of curbs, and the UrbanCurbGutterGeneral subassembly can't model them all. Sometimes you may need a mountable curb, or perhaps you need a shoulder instead. In those cases, the Corridor Modeling Catalog provides many alternatives:

UrbanCurbGutterValley (1, 2, or 3)

The UrbanCurbGutterValley subassemblies are great if you need mountable curbs. UrbanCurbGutterValley 1, 2, and 3, shown in Figure 8.26, Figure 8.27, and Figure 8.28 respectively, vary slightly in how they handle the sub-base slope. UrbanCurbGutterValley 1 also differs because it comes to a point instead of offering a width at the top of curb.

Figure 8.26 The UrbanCurb GutterValley1 subassembly help diagram

Figure 8.27 The UrbanCurb GutterValley2 subassembly help diagram

Figure 8.28 The UrbanCurb GutterValley3 subassembly help diagram

BasicShoulder

BasicShoulder (see Figure 8.29) is another simple yet effective subassembly for use with road sections that require a shoulder. The predefined shape for this subassembly is Pave1, which is good if you are planning to treat this as a paved shoulder and quantify the material with the Pave1 from a lane.

Figure 8.29 The BasicShoulder subassembly help diagram

ShoulderExtendSubbase and ShoulderExtendAll

Shoulders that can work with your lanes in a superelevation situation, as these two do, are extremely helpful. These two subassemblies, shown in Figure 8.30, will “play nice” with your breakover-removal settings, as you will see in Chapter 12, “Superelevation.”

Figure 8.30 ShoulderExtend- Subbase subassembly help diagram (top) and ShoulderExtendAll subassembly help diagram (bottom)

Editing an Assembly

As you saw earlier in this chapter, the AutoCAD Properties palette is an option for changing subassembly parameters for one or more subassemblies of the same type. However, there are a handful of settings that can only be controlled in the Civil 3D Subassembly Properties. For example, the side (left or right) is a parameter must be changed in the Subassembly Properties.

Editing a Single Subassembly's Parameters

Once your assembly is created, you can edit individual subassembly components as follows:

1. Pick the subassembly component you'd like to edit.

This will bring up the Subassembly contextual tab.

2. From the contextual tab, ⇒ Modify Subassembly panel choose the Subassembly Properties option.

The Subassembly Properties dialog appears.

3. Switch to the Parameters tab, as shown in Figure 8.31, to access the same parameters you saw in the AutoCAD Properties palette when you first placed the subassembly.

Figure 8.31 Subassembly Properties – Parameters tab

4. Click the Subassembly Help button at the bottom right of the dialog if you want to access the help page that gives detailed information about the use of this particular subassembly.

Do not confuse the Subassembly Help button with the plain Help button, which will just give you help on the Subassembly Properties dialog.

5. Close the help file when you've finished viewing it.

6. On the Parameters tab of the Subassembly Properties, click inside any field in the Default Input Value column to make changes.

Editing the Entire Assembly

Sometimes it's more efficient to edit all the subassemblies in an assembly at once. To do so, pick the assembly baseline marker, or any subassembly that is connected to the assembly you'd like to edit. This time, select the Assembly Properties option from the Modify Assembly panel of either the Subassembly or Assembly contextual tab to display the Assembly Properties dialog, as shown in Figure 8.32.

Figure 8.32 Assembly Properties – Information tab

Renaming the Assembly

The Information tab on the Assembly Properties dialog shown in Figure 8.32 gives you an opportunity to rename your assembly and provide an optional description. It is good practice to be consistent and detailed in your assembly names (for example, Divided 4-Lane 12′ w Paved Shoulder). With informative assembly names, you will eliminate much of the guesswork when it comes to building corridors later on.

Changing Parameters

The Construction tab in the Assembly Properties dialog, as shown in Figure 8.33, houses each subassembly and its parameters. At the top of the dialog you can change the Assembly Type setting using the drop-down list. In addition, you can change the parameters for individual subassemblies by selecting the subassembly in the Item pane on the left side of the Construction tab, and changing the desired parameter in the Input Values pane on the right side.

Figure 8.33 Assembly Properties – Construction tab

Renaming Groups and Subassemblies

Note that the left side of the Construction tab displays a list of groups. Under each group is a list of the subassemblies in use in your assembly. A new group is formed every time a subassembly is connected directly to the assembly baseline marker.

With the new side autodetection implemented in Civil 3D 2013, you will notice that the groups have already been named Right and Left with the appropriate symbol next to the group name, as shown in Figure 8.33. The subassemblies in each group appear in the same order in which they were originally placed, usually from the inside out. The first subassembly under the Right group is LaneSuperelevationAOR. If you dig into its parameters on the right side of the dialog, you'll learn that this lane is attached to the right side of the assembly marker, the UrbanCurbGutterGeneral is attached to right side of the LaneSuperelevationAOR, and the UrbanSidewalk is attached to the right side of the UrbanCurbGutterGeneral. In this example, the next group, Left, is identical but attached to the left side of the assembly baseline marker.

If you want, you can rename any of the groups or subassemblies on the Construction tab of the Assembly Properties dialog by right-clicking on the group or subassembly you wish to rename and choosing Rename. From this same right-click menu you can also delete the group or subassembly.

There is no official best practice for renaming your groups and subassemblies, but you may find it useful to keep the designation of what type of subassembly it is or other distinguishing features. For example, if a lane is to be designated as a transition lane or a generic link used as a ditch foreslope, it would be useful to name them descriptively.

Creating Assemblies for Nonroad Uses

There are many uses for assemblies and their resulting corridor models aside from road sections. The Corridor Modeling Catalog also includes components for retaining walls, rail sections, bridges, channels, pipe trenches, and much more. In Chapter 10, you'll use a channel assembly and a pipe-trench assembly to build corridor models. Let's investigate how those assemblies are put together by building a channel assembly for a stream section:

1. Start a new blank drawing from the _AutoCAD Civil 3D (Imperial) NCS template that ships with Civil 3D. For metric users, use the _AutoCAD Civil 3D (Metric) NCS template, or continue working in your drawing from the first exercise in this chapter.

2. Confirm that your Tool Palettes window is showing the subassembly set (Imperial or metric) appropriate for your drawing units.

3. From the Home tab, ⇒ Create Design panel choose Assembly ⇒ Create Assembly.

The Create Assembly dialog opens.

4. Enter Channel in the Name text box.

5. Set Assembly Type to Other.

6. Confirm that Assembly Style is set to Basic and that Code Set Style is set to All Codes, and click OK.

7. Pick a location in your drawing for the assembly — somewhere in the center of your screen where you have room to work is fine — to place your red assembly baseline marker.

8. Locate the Trench Pipes tab on the Tool Palettes window.

9. Click the Channel button on the Tool Palettes window.

The AutoCAD Properties palette appears.

10. Locate the Advanced Parameters section of the Design tab on the AutoCAD Properties palette.

You'll place the channel with its default parameters and make adjustments through the Assembly Properties dialog, so don't change anything for now. Note that there is no Side parameter. This subassembly will be centered on the assembly baseline marker.

11. At the Select marker point within assembly or [Insert Replace Detached]: prompt, select the red assembly baseline marker, and a channel is placed on the assembly (see Figure 8.34).

Figure 8.34 The Channel subassembly with default parameters

12. Press Esc to leave the assembly creation command and dismiss the palette.

13. Right-click the assembly baseline marker and select Assembly Properties.

The Assembly Properties dialog appears.

14. Switch to the Construction tab.

Notice that while the typical road assembly in the previous exercise generated a Left group and a Right group, the Channel subassembly generated a Centered group.

15. Select the Channel entry on the left side of the dialog (under the Centered group).

16. Click the Subassembly Help button located at the bottom right on the dialog's Construction tab.

The Subassembly Reference page of the AutoCAD Civil 3D 2013 help file appears.

17. Familiarize yourself with the diagram, as shown in Figure 8.35, and the input parameters for the Channel subassembly.

Figure 8.35 The Channel subassembly help diagram

Especially note the Attachment Point, Bottom Width, Depth, and Sideslope parameters. The attachment point indicates where your baseline alignment and profile will be applied.

18. Minimize or close the help file.

To match the engineer's specified design, you need a stream section 6′ (2 m) deep with a 3′ (1 m)-wide bottom, 1:1 sideslopes, and no backslopes.

19. Change the following parameters in the Assembly Properties dialog, leaving all other parameters at their default values:

Depth: 6′ (2 m)

Bottom Width: 3′ (1 m)

Sideslope: 1 (This value will automatically change to be displayed as 1:1.)

Left and Right Backslope Width: 0′ (0 m)

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Zero Subassembly Values

There are some subassemblies that do not like zero values, so you may be taught to enter 0.001 or some other value that is so small that it is as if you enter 0. However, there are also some subassemblies that like zero values. If you look in the help file for the Channel subassembly, you will notice that in the Behavior section it explains that if a zero value is specified for left or right extensions and backslope widths, those links are omitted or are not drawn. So in this case a zero is what you want, but be sure to check the help files before using a zero in your subassemblies!

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20. Click OK, and confirm that your completed assembly looks like Figure 8.36.

Figure 8.36 The channel assembly with customized parameters

You may keep this drawing open to continue on to the next exercise, or use the finished copy of this drawing available from the book's web page (ChannelAssembly_FINISHED.dwg or ChannelAssembly_METRIC_FINISHED.dwg).

A Pipe Trench Assembly

Projects that include piping, such as sanitary sewers, storm drainage, gas pipelines, or similar structures, almost always include trenching. The trench must be carefully prepared to ensure the safety of the workers placing the pipe, as well as provide structural stability for the pipe in the form of bedding and compacted fill.

The corridor is an ideal tool for modeling pipe trenching. With the appropriate assembly combined with a pipe-run alignment and profile, you can not only design a pipe trench but also use cross-section tools to generate section views, materials tables, and quantity takeoffs. The resulting corridor model can also be used to create a surface for additional analysis.

The following exercise will lead you through building a pipe trench corridor based on an alignment and profile that follow a pipe run, and a typical trench assembly:

1. Start a new blank drawing from the _AutoCAD Civil 3D (Imperial) NCS template that ships with Civil 3D. For metric users, use the _AutoCAD Civil 3D (Metric) NCS template, or continue working in your drawing from the previous exercise.

2. Confirm that your Tool Palettes window is showing the subassembly set (Imperial or metric) appropriate for your drawing units.

3. From the Home tab, ⇒ Create Design panel choose Assembly ⇒ Create Assembly.

4. Enter Pipe Trench in the Name text box to change the assembly's name.

5. Set Assembly Type to Other.

6. Confirm that Assembly Style is set to Basic and Code Set Style is set to All Codes, and click OK.

7. Pick a location in your drawing for the assembly; somewhere in the center of your screen where you have room to work is fine.

8. Locate the Trench Pipes tab on the Tool Palettes window.

9. Click the TrenchPipe1 button on the Tool Palettes window.

The AutoCAD Properties palette appears.

10. Locate the Advanced section of the Design tab on the AutoCAD Properties palette.

This section lists the TrenchPipe1 parameters. You'll place TrenchPipe1 with its default parameters and make adjustments through the Assembly Properties dialog, so don't change anything for now. Note that similar to the Channel subassembly, there is no Side parameter. This subassembly will be placed centered on the assembly baseline marker.

11. At the Select marker point within assembly or [Insert Replace Detached]: prompt, select the assembly baseline marker. A TrenchPipe1 subassembly is placed on the assembly as shown here:

12. Press Esc to leave the assembly creation command and dismiss the AutoCAD Properties palette.

13. Select the assembly baseline marker to activate the Assembly contextual ab.

14. From the Assembly contextual tab ⇒ Modify Assembly panel choose Assembly Properties.

The Assembly Properties dialog appears.

15. On the Construction tab, select the TrenchPipe1 assembly entry on the left side of the dialog.

16. Click the Subassembly Help button located at the bottom right.

The Subassembly Reference page of the AutoCAD Civil 3D 2013 Help file appears.

17. Familiarize yourself with the diagram, shown in the following graphic, and with the input parameters for the TrenchPipe1 subassembly.

In this case, the profile grade line will attach to a profile drawn to represent the pipe invert. Because the trench will be excavated deeper than the pipe invert to accommodate gravel bedding, you'll want to provide information for the bedding depth parameter. Also note under the Target Parameters that this subassembly requires a surface target to determine where the sideslopes terminate.

18. Minimize or close the help file.

To match the engineer's specified design, the pipe trench should be 3′ (1 m) deep and 4′ (1.3 m) wide with 2:1 sideslopes and 1′ (0.3 m) of gravel bedding.

19. In the Assembly Properties dialog, change the following parameters, leaving all other parameters at their default values:

Width: 4′ (1.3 m)

Sideslope: 2 (This value will automatically change to be displayed as 2:1.)

Bedding Depth: 1′ (0.3 m)

Offset To Bottom: 3′ (1 m)

20. Click OK.

21. Confirm that your completed assembly looks like the graphic shown here.

You may keep this drawing open to continue on to the next exercise, or use the finished copy of this drawing available from the book's web page (PipeTrenchAssembly_FINISHED.dwg or PipeTrenchAssembly_METRIC_FINISHED.dwg).

This assembly will be used to build a pipe-trench corridor in Chapter 10.

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Specialized Subassemblies

Despite the more than 100 subassemblies available in the Corridor Modeling Catalog, sometimes you may not find the perfect component. Perhaps none of the channel assemblies exactly meet your design specifications, and you'd like to make a more customized assembly, or neither of the sidewalk subassemblies allows for the proper boulevard slopes. Maybe you'd like to try to do some preliminary lot grading using your corridor, or mark a certain point on your subassembly so that you can extract important features easily.

You can handle most of these situations by using subassemblies from the Generic Subassembly Catalog (see Figure 8.37). These simple yet flexible components can be used to build almost anything, although they lack the coded intelligence of some of the more intricate assemblies (such as knowing if they're paved, grass, or similar, and understanding things like sub-base depth, and so on).

Figure 8.37 The Generic Subassembly tool palette

Using Generic Links

Let's look at two examples where you might take advantage of generic links.

The first example involves the typical road section you built in the first exercise in this chapter. You saw that UrbanSidewalk doesn't allow for differing cross-slopes for the inside boulevard (terrace), sidewalk, and outside boulevard (buffer strip). If you need a 3′ (1 m)-wide terrace with a 3 percent slope, and then a 5′ (1.5 m) sidewalk with a 2 percent slope, followed by another buffer strip that is 6′ (2 m) wide with a slope of 5 percent, you can use generic links to assist in the construction of the proper assembly.

In this exercise we will be creating a new assembly based on the typical road assembly made in the first exercise. Therefore, any of the previously saved files (which you can download from this book's web page) can be used, if you do not have one open from a previous exercise.

Figure 8.38 The completed Urban Single-Lane assembly from the first exercise (top) and the Urban Single-Lane with Terraced Sidewalks assembly (bottom)

You may keep this drawing open to continue on to the next exercise, or use the finished copy of this drawing available from the book's web page (GenericLinks_FINISHED.dwg or GenericLinks_METRIC_FINISHED.dwg).

You've now created a custom sidewalk terrace for a typical road.

Daylighting with Generic Links

The next example involves the channel section you built earlier in this chapter. This exercise will lead you through using the LinkSlopetoSurface generic subassembly, which will provide a surface target to the channel assembly that will seek the target assembly at a 25 percent slope. For more information about surface targets, see Chapter 10.

In this exercise, you will be creating another new assembly based on the channel assembly made in the second exercise; therefore, any of the previously saved files (which you can download from this book's web page) can be used, if you do not have one open from a previous exercise. You do not need to have the other previous exercises completed to continue.

Figure 8.39 The completed channel assembly

You may keep this drawing open to continue on to the next exercise, or use the finished copy of this drawing available from the book's web page (ChannelLinkDaylight_FINISHED.dwg or ChannelLinkDaylight_METRIC_FINISHED.dwg).

Adding a surface link to the channel assembly provides a surface target for the assembly. Now that you've added the LinkSlopetoSurface, you will be able to specify your existing ground as the surface target for a corridor, and the subassembly will grade between the top of the bank and the surface for you. You can achieve additional flexibility for connecting to existing ground with the more complex daylight subassemblies, as discussed in the next section.

Working with Daylight Subassemblies

In previous examples, we worked with a generic daylight subassembly, but now let's take a closer look at what they can do for you.

A daylight subassembly tells Civil 3D how to extend a link to a target surface. The instructions might include a ditch or berm before looking for existing ground. Others provide a straight shot but with contingencies for certain design conditions. Figure 8.40 shows the many options you have for adding a daylight subassembly to an assembly.

Figure 8.40 Daylight subassemblies in the Tool Palettes window

In the following exercise, you'll use the DaylightInsideROW subassembly. This subassembly contains parameters for specifying the maximum distance from the centerline or offset alignments. If the 4:1 slope hits the surface inside the right-of-way (ROW), no adjustment is made to the slope. If 4:1 causes the daylight to hit outside of the ROW, the slope adjusts to stay inside the specified location.

In this exercise you will be creating a new assembly based on the typical road assembly you made in the first exercise; therefore, any of the previously saved files (which you can download from this book's web page) can be used, if you do not have one open from a previous exercise.

Figure 8.41 An assembly with the DaylightInsideROW subassembly attached to each side

You may keep this drawing open to continue on to the next exercise, or use the finished copy of this drawing available from the book's web page (DaylightROWAssembly_FINISHED.dwg or DaylightROWAssembly_METRIC_FINISHED.dwg).

When to Ignore Daylight Input Parameters

The first time you attempt to use many daylight subassemblies, you may become overwhelmed by the sheer number of parameters.

The good news is that many of these parameters are unnecessary for most uses. For example, many daylight subassemblies, such as DaylightGeneral (shown here), include multiple cut-and-fill widths for complicated cases where the design may call for test scenarios. If your design doesn't require this level of detail, leave those parameters set to zero.

Some daylight subassemblies include guardrail options. If your situation doesn't require a guardrail, leave the default parameter set to Omit Guardrail and ignore it from then on. Another common, confusing parameter is Place Lined Material, which can be used for riprap or erosion-control matting. If your design doesn't require this much detail, ensure that this parameter is set to None, and ignore the thickness, name, and slope parameters that follow.

If you're ever in doubt about which parameters can be omitted, investigate the help file for that subassembly.

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Alternative Daylight Subassemblies

Over a dozen daylight subassemblies are available, varying from a simple cut-fill parameter to a more complicated benching or basin design. Your engineering requirements may dictate something more challenging than the exercise in this section. Here are some alternative daylight subassemblies and the situations where you might use them. For more information on any of these subassemblies and the many other daylighting choices, see the AutoCAD Civil 3D 2013 Subassembly Reference page in the help file.

DaylightToROW and DaylightInsideROW

The DaylightToROW subassembly differs slightly from the DaylightInsideROW, as shown in Figure 8.42. DaylightToROW constantly adjusts the slope to stay a certain distance away from your ROW, as specified by the Offset Adjustment input parameter. For example, you can have a ROW alignment specified, but use this subassembly to tell Civil 3D to always stay 3′ inside the ROW line. The DaylightInsideROW uses the typical slope but adjusts up to a maximum slope in order to stay inside of the ROW. In both subassemblies, you must specify an offset value or an offset target to use as the ROW.

Figure 8.42 DaylightToROW subassembly help diagram (top) and DaylightInsideROW subassembly help diagram (bottom)

BasicSideSlopeCutDitch

In addition to including cut-and-fill parameters, the BasicSideSlopeCutDitch subassembly (see Figure 8.43) creates a ditch in a cut condition. This is most useful for road sections that require a roadside ditch through cut sections, but omit it when passing through areas of fill. If your corridor model is revised in a way that changes the location of cut-and-fill boundaries, the ditch will automatically adjust. Note that this subassembly is located on the Basic tab whereas the other subassemblies in this section are located on the Daylight tab.

Figure 8.43 The BasicSide- SlopeCutDitch subassembly help diagram

When you insert this subassembly you will notice that it does not look anything like the help diagram and instead will display the “LayoutMode” text on the design assembly, as shown in Figure 8.44. This will not display on the completed corridor. There are several subassemblies where this will occur — which is another good reason to always check the help file for an accurate representation of what the final product will look like.

Figure 8.44 The BasicSide- SlopeCutDitch in layout mode

DaylightBasin

Many engineers must design berms to contain roadside swales when the road design is in the fill condition. The process for determining where these berms are required is often tedious. The DaylightBasin subassembly (see Figure 8.45) provides a tool for automatically creating these “false berms.” The subassembly contains parameters for the specification of a basin (which can be easily adapted to most roadside ditch cross sections as well) and parameters for containment berms that appear only when the subassembly runs into areas of roadside cut.

Figure 8.45 The DaylightBasin subassembly help diagram

Advanced Assemblies

As you get to know Civil 3D better, you will want it to do more for you. With the tools you are given and your own creativity and problem-solving skills, Civil 3D can create some complex designs. Offset assemblies and marked point assemblies are powerful tools you have at your fingertips.

Offset Assemblies

Offset assemblies are an advanced option when you want to model a coordinating component of the design whose cross section is related to the main assembly. An example of where an offset assembly would be helpful is a main road adjacent to a meandering bike path. The bike path generally follows the main road, but its alignment is not always parallel and the profile might be altogether different. Figure 8.46 shows what the assembly for a bike path to the left of a road would look like.

Figure 8.46 An example of an assembly with an offset to the left representing a bike path

To use an offset assembly, from the Home tab ⇒ Create Design panel choose Assembly ⇒ Add Assembly Offset. You will be prompted to select the main assembly and place the offset in the graphic. The location of the offset assembly in relation to the main assembly will have no effect on the final design.

Once the offset assembly is placed, the construction of the offset assembly is identical to any other assembly. We will use an example of an assembly with an offset in Chapter 11, “Advanced Corridors, Intersections, and Roundabouts.”

Marked Points and Friends

The marked point assembly is a small but powerful subassembly found in the Generic palette. It consists of a single marker, and you can place it on an assembly to flag a location. You can use the marked point by itself to generate a feature line where no coded marker currently exists, say in the midpoint of a lane link. Where marked points really shine are when used with one of the subassemblies designed to look for a marked point.

When using a marked point, name it right away, and make note of that name for using it with its “friends” (Figure 8.47).

Figure 8.47 Name the marked point in the Advanced Parameters

Linking to a Marked Point

In the example shown in Figure 8.48, a LinkToMarkedPoint2 subassembly is placed on the right side of the bike path pavement. The LinkToMarkedPoint2 subassembly has been created to look for the marked point on the left side of the sidewalk buffer.

Figure 8.48 Add the name of the marked point before you place it on the assembly

Before placing a marked point subassembly, change the name of the marked point in the Advanced Parameters. Before you create a subassembly that references a marked point, make certain that you have properly defined the marked point that it references. Be sure to reference this marked point by name with the subsequent subassemblies that reference it before you place it on your assembly.

At this stage, the geometry for a subassembly using a marked point is not known. The final geometry will be determined when you plug it into a corridor. All subassemblies that use the marked point will appear with the “Layout Mode” placeholder. Subassemblies designed to look for a marked point include the following:

• Channel
• ChannelParabolicBottom
• LinkToMarkedPoint
• LinkToMarkedPoint2
• LinkSlopesBetweenPoints
• MedianDepressed
• MedianRaisedConstantSlope
• MedianRaisedWithCrown
• OverlayBrokenBackBetweenEdges
• OverlayBrokenBackOverGutters
• OverlayParabolic
• UrbanReplaceCurbGutter (1 and 2)
• UrbanReplaceSidewalk

Making Sure Your Marked Point Processes

Always place the marked point before the links that use it to avoid having to reorder subassemblies in the Construction tab of Assembly Properties. If the marked point is listed below the subassembly that needs it in the Construction tab, Civil 3D will not process it.

To reorder subassemblies in this dialog, right-click the subassembly and select Move Up or Move Down as needed.

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Organizing Your Assemblies

The more geometry changes that occur throughout your corridor, the more assemblies you will have. Civil 3D offers several tools to keep your assemblies organized and available for future use.

Storing a Customized Subassembly on a Tool Palette

Customizing subassemblies and creating assemblies are both simple tasks. However, you'll save time in future projects if you store these assemblies for later use.

A typical jurisdiction usually has a finite number of allowable lane widths, curb types, and other components. It would be extremely beneficial to have the right subassemblies with the parameters already available on your Tool Palettes window.

The following exercise will lead you through storing a customized subassembly on a tool palette.

In this exercise you will be storing some of the subassemblies you made in earlier exercises; therefore, any of the previously saved files (which you can download from this book's web page) can be used, if you do not have one open from a previous exercise.

You can only add a tool from a saved drawing, so make sure you save the drawing you are working in before following these steps:

1. Be sure your Tool Palettes window is displayed.

2. Right-click the Tool Palettes control bar located at the top of the window, and select New Palette to create a new tool palette.

3. Enter My Road Parts in the Name text box.

4. Select the sidewalk sub-base from the Urban Single-Lane assembly.

You'll know it's selected when you can see it highlighted and the grip appears.

5. Click on the dashed portion of the subassembly (i.e., a subassembly marker, not the grip point) and drag the assembly into the Tool Palettes window.

It may take you several tries to get the click-and-drag timing correct, but it will work. You'll know it is working when the cursor appears with a plus sign in the tool palette.

When you release the mouse button, an entry appears on your tool palette with the name of the subassembly component that you are adding as well as a graphic of the subassembly.

6. Right-click this entry, and select the Properties option.

The Tool Properties dialog appears (see Figure 8.49).

Figure 8.49 The Tool Properties dialog

7. If desired, change the image, description, and other parameters in the Tool Properties dialog, and click OK.

8. Try this process for several lanes and curbs in the drawing.

The resulting tool palette looks similar to Figure 8.50.

Figure 8.50 A tool palette with three customized subassemblies

Note the tool palette entries for each subassembly point to the location of the Subassembly .NET directory, and not to this drawing. If you share this tool palette, make sure the subassembly directory is either identical or accessible to the person with whom you're sharing.

Storing a Completed Assembly on a Tool Palette

In addition to storing individual subassemblies on a tool palette, it's often useful to warehouse entire completed assemblies. Many jurisdictions have several standard road cross sections; once each standard assembly has been built, you can save time on future similar projects by pulling in a prebuilt assembly.

The process for storing an assembly on a tool palette is nearly identical to the process of storing a subassembly. Simply select the assembly baseline, hover your cursor over the assembly baseline, left-click, and drag to a palette of your choosing.

It's usually a good idea to create a library drawing in a shared network location for common completed assemblies, and to create all assemblies in that drawing before dragging them onto the tool palette. By using this approach, you'll be able to test your assemblies for validity before they are rolled into production. Alternatively, you can right-click on the new palette name and choose Import Subassemblies to display the Import Subassemblies dialog. Here you can choose a source file and then specify whether you want the subassemblies from that source file to import into the palette (optional) and/or the Catalog Library/My Imported Tools.

Organizing Assemblies within Prospector

There are multiple features that help you keep a drawing with many assemblies organized. In Prospector, you will see your listing of assemblies and an Unassigned Subassemblies entry.

Unassigned subassemblies are orphaned parts that are not attached to any main assembly. They may be left over from some assembly customization or they may just be a mistake. In either case, you will want to clean them out. Right-click on the Assemblies collection and select Erase All Unreferenced Assemblies.

In this same right-click menu, you can also choose to remove the display of the assemblies from modelspace. This hides the display of the assembly but retains its definition in the drawing.

You can still use a hidden assembly in a corridor. If you need it visible again for editing purposes, right-click on the assembly and select Insert To Modelspace.

The niftiest part of this new method of organizing assemblies is that they can now be part of your Civil 3D template without having them visible.

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The Bottom Line