AutoCAD Civil 3D General Discussion

AutoCAD Civil 3D General Discussion

Active Member
Posts: 9
Registered: ‎12-21-2012
Message 1 of 5 (331 Views)

Grading Subdivisions

331 Views, 4 Replies
10-16-2013 02:21 PM


   I am new to Civil 3D, I am working with Civil 3D 2014, I played with 2009 back in 2008 and before that it was Land desktop.  I don't know if I am not following a standard workflow, or if I am missing a step.


Here is what I am doing.

  1. Build the EG from contours.
  2. Layout the CL for the ROW and convert to a horizontal alignments.
  3. Create the profiles.
  4. Design the vertical alignment in the profile.
  5. Create the assemblies for the different types of road sections.
  6. Full profile, pavement width assembly, the curb return assembly, the daylight left / right, 1/2 side left / right, and pavement width left / right.
  7. Build the corridor, set the target surface as EG or FG, depending on where the section of the corridor is located. (At the edge of the property to EG, then after the first building pad to FG)
  8. This is where I have a thought something is wrong. If I am grading the entire site, why would I have the ROW grade to the EG, when I will need the surface to grade from the ROW to the closest building pads?
  9. Create the intersections, using the different types of assemblies, per the ROW sections.
  10. Create feature lines and use elevation editor to set all the elevations around the pad.
  11. Using the Grading creation tool, grade to surface, using a 2:1 side slope. Then adding an infill to the pad.

 I keep having the file crash after grading about 10 lots. I recover and it works find, but then the file runs very slow, and will crash. I haven't taken any classes in Civil 3d, and am looking for one in my area, but does anyone have any ideas of what I am doing wrong?


I am use to creating the vertical surface then creating points along the CL, TBC, FL, BOW then creating break lines along the points. Then create a break line for the pads, and build the FG contours from these break lines.  


Thanks in advance for any help,


Valued Mentor
Posts: 468
Registered: ‎09-14-2010
Message 2 of 5 (315 Views)

Re: Grading Subdivisions

10-16-2013 04:01 PM in reply to: TROYDAWES

You might want to rough grade the pads first and target your roads based on the new grading. Might save you a little heartache. Instead of doing "Breaklines" you can use Feature Lines and set transitions and elevations.

Andrew Ingram

Civil 3D x64 2012
Win 7 x64 Ultimate
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*Expert Elite*
Posts: 2,318
Registered: ‎09-04-2006
Message 3 of 5 (300 Views)

Re: Grading Subdivisions

10-16-2013 06:48 PM in reply to: TROYDAWES

With regard to your item #8, you will typically want to grade from the edge of the roadway or sidewalk to the pads, so the ROW usually doesn't come into play for that scenario.


As to when to tie the roads into the terrain, I like to first see how the road fits the terrain before moving on to pad grading. The visual feedback can help determine if adjustments are needed. There are likely some techniques you can use to preserve the daylighting for reference while you develop the pad grading if  it helps.

Neil Wilson (a.k.a. neilw)
Infrastructure Suite/C3D 2013, LDT 2004, Power Civil v8i SS1
WIN 7 64 PRO
HP Pavillion h8xt, i7 2600, 12 GB
RADEON 6450, 1 GB
Valued Mentor
Posts: 1,131
Registered: ‎01-07-2011
Message 4 of 5 (275 Views)

Re: Grading Subdivisions

10-17-2013 06:13 AM in reply to: TROYDAWES

" If I am grading the entire site"


If this is a typical new subdivision and the above is true, then the Corridors for the internal streets typically do not use any surface targets in the typical workflow. They are simply a part of FG.



Fred Ernst, PE
C3D 2015
Ernst Engineering
*Expert Elite*
Posts: 2,524
Registered: ‎05-21-2008
Message 5 of 5 (266 Views)

Re: Grading Subdivisions

10-17-2013 07:13 AM in reply to: TROYDAWES
With regard to #1 on your list, you should read this:

We typically don't target any surface with our corridors. We use the corridor surface to set the front of the lots.

Credit where credit is due! Give kudos or accept as solution whenever you can.

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