7. To complete the left side of the assembly, repeat steps 4 through 6, and change the Side
parameter to the Left option.
8. The completed assembly should look like Figure 10.29.
Figure 10.29
The completed Channel
Adding a surface link to a Channel assembly provides a surface target for the assembly. When
you’re designing a channel, it’s important to tie into existing ground. In its original form, the
Channel subassembly doesn’t include a target parameter that would allow you to choose an exist-
ing ground; therefore, you’d need to do quite a bit of hand grading between the top of the bank
and existing ground. Now that you’ve added the LinkSlopetoSurface, you can specify your exist-
ing ground as the surface target, and the subassembly will grade between top of the bank and the
surface for you. You can achieve additional flexibility for connecting to existing ground with the
more complicated Daylight subassemblies, as discussed in the next section.
Working with Daylight Subassemblies
Most typical sections have many absolute requirements, such as a cross slope for a lane or the
height of a curb. But from that last engineered point on the left and right of a typical section, some
design decisions have flexibility.
In the example of the typical road section from the first part of this chapter, the engineer needs
to design the grade from the last buffer strip until the section ties into existing ground. The location
where the design meets existing ground is known as daylighting.
Daylight subassemblies provide tools to assist the engineer in meeting the design intent
between existing ground and the typical section. Some Daylight subassemblies are shown in
Figure 10.30.
Enhancing an Assembly with a Daylight Subassembly
Using the typical road section from the first exercise in this chapter, your subdivision layout allows
for grading 25
from the end of the sidewalk buffer strip. This grading has a 4:1 maximum for both
cut-and-fill situations. In the following exercise, you’ll use the DaylightMaxWidth subassembly,
which contains parameters for specifying the grading width and the maximum cut-and-fill slopes:
1. Open the Daylight Start.dwg file (which you can download from
masteringcivil3d2010), or continue working in any drawing from this chapter that con-
tains a typical road section.
2. Zoom in on the typical road-section assembly.
3. Locate the Imperial-Daylight tab on the tool palette. Position the palette on your screen so
that you can clearly see the assembly baseline.
4. Click the DaylightMaxWidth button on the tool palette. The AutoCAD Properties palette
appears. Position the palette on your screen so that you can still clearly see both the
assembly baseline and the tool palette.
Figure 10.30
Some Daylight
subassemblies in the
Corridor Modeling
5. Locate the Advanced section of the Design tab on the AutoCAD Properties palette. This
section lists the parameters for the DaylightMaxWidth subassembly. Change the follow-
ing parameters to create the daylight as required:
Side: Right
Cut Slope: 4:1 (or 25%)
Fill Slope: 4:1 (or 25%)
Max Width: 25
6. The command line states Select marker point within assembly or [RETURN for
Detached]:. Select the circular point marker on the farthest right link. The subassembly
appears as in Figure 10.31.
Figure 10.31
Placement of the
7. Press Esc to exit the assembly-creation command.
8. Pick the DaylightMaxWidth subassembly, and then choose Subassembly Properties from
the Modify Subassembly panel.
9. Switch to the Parameters tab in the Subassembly Properties dialog.
10. Click the Subassembly Help button in the lower-right corner. The Subassembly Reference
opens in a new window. Familiarize yourself with the options for the DaylightMaxWidth
subassembly, especially noting the optional parameters for a lined material, a mandatory
daylight surface target, and an optional alignment target that can be used for the maxi-
mum width.
11. Minimize the Subassembly Reference window.
12. To complete the left side of the assembly, repeat steps 3 through 6, changing the Side
parameter for each subassembly to the Left option. The completed assembly should look
like Figure 10.32.
Figure 10.32
An assembly with the
daylight subassembly
properly attached
When to Ignore Parameters
The first time you attempt to use many Daylight subassemblies, you may become overwhelmed by
the sheer number of parameters, as shown h ere.

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