Get Stripped

No, this isn’t some kind of weird SPAM post or hack or anything. This is, in fact, a genuine Civil 3D article. Actually, it’s a little pun regarding the upcoming Autodesk University in Las Vegas. You know…The Strip. I had to throw in the obvious definition for Jason’s sake 🙂

I’ve been plagued recently with people asking how to calculate stripping using a corridor. They know the old standby method, you know the one; copy your OG surface and drop it by the depth of material to be stripped and then calculate cut and fill to this new surface. It works, but this way is cooler.

Let’s see how we can handle stripping in a corridor, shall we?

We want this to happen
The green is what volumes would normally be calculated to.
The black is the stripping material to be removed.
Both together is the total fill after stripping.
The red is the OG section.

First you need to add the StrippingPavement subassembly to the end of your daylight subassemblies. I’m only showing one side, but you’ll need to do this for both sides.
I’m using the DaylightMultiIntercept subassembly for my daylight and it doesn’t seem to work correctly when I attach the stripping to the fill lines (green), but it works great when I attach it to the red cut lines. Go figure.

This image is from the help page:
This SA inserts links parallel to a surface at a depth you specify from the daylight intersection back to the corridor baseline. Since it needs to know which surface to insert links parallel to, you’ll need to assign surface targets for this subassembly in your corridor.

After rebuilding the corridor we have this:

Now it’s volume time.

Volumes can be calculated by surfaces or corridor materials. This IS NOT a corridor material. That said, we will need to define corridor surfaces.
One for the corridor Datum.
One for the stripped OG surface.
When you are creating the stripped OG surface you will see two links that come in when you add the StrippingPavement subassembly. I have added just the stripping. If I were using the foreslope option, I would add both.
In order to calculate volumes from these surfaces in cross section, you need to define materials. I’m going to assume you know how to do this. There is one detail that is important here, however. Normally the EG below is set to your OG surface. for stripping calculations I have set it to my stripping corridor surface. The DATUM, as usual, is set to my corridor datum surface.

We’re almost done.

The last thing we need to calculate is the actual volume of material stripped. Add another criteria to your materials list; this time using the OG surface and the stripping surface. The completed materials list is shown below.

Of course, it wouldn’t be complete without some tables.image

Here is what a section looks like when in both cut and fill.

Well, thanks for tuning in. Til next time,



  1. Jason Hickey says:

    Glad you were able to throw in the definition – my wife doesn’t allow me to go to clubs like that, so I was using the other definition and actually had my pants off to see if I even NEEDED to read the rest of the article 😉

    Seriously, I’ve seen that subassembly and always just grazed over it…I’ll be honest, I’m a “copy and lower” guy, up until now. Thanks for the hint!

  2. Matthew Nashmi says:

    Is it possible to differentiate stripping area when the road is either cut or fill.

    For example is it possible to have the following end areas calculated seperately.

    strip area in road cut
    strip area in road fill

  3. Brent Miller says:


    Your section is to idealistic. Add some ditches to the assembly and have the back slopes daylight. Then seperate the topsoil quantity from the total volume since organic material can not be used in road construction. The idea hear is to have the road volumes balance for the entire project without topsoil volume. There are other cases where the topsoil need only be stripped for a portion of the coridor, for instance a curb & gutter street. If the topsoil is stripped from back of curb to back of curb, then used latter to backfill the boulevard you can see that it would be nice to have a combined surface using the corridor stripping surface and existing ground surface for your earthwork volume comparison.

  4. Matt Kolberg says:

    Well, I never advertised it as one size fits all. It works for 95% of my projects. For the other 5% I’ll use another technique.

  5. Allen David says:

    Hey guys. I have just started using civil 3d, and im wondering what is the best way to get the quantities for undercut material. I have not seen subassembly that perform this…help! help!!