Civil 3D Fundamentals – Calculating Quantities from a Corridor

Lately, I’ve been seeing quite a few questions on the Civil 3D discussion group regarding volumes and quantities. Volumes can be pretty straightforward, but individual material quantities can be a bit more in-depth. Following the link will hopefully illustrate this process a bit better.

First of all, you have to have a sample line group of you want to calculate quantities. It should go without saying that you have to sample the materials that you want to calculate the quantities of – if they’re not sampled, you can’t include them in any calculations. That seems to be a sticking point with some people, so I’ll repeat it:


To make sure my materials work, I always start with a corridor. To make sure that I have something other than just a singular layer of asphalt, I typically use the LaneOutsideSuper subassembly for my lanes. This gives me 4 potential layers of materials, known as Pave1, Pave2, Base, and Subbase. Do you know how figured out which layer was which on this subassembly? I went to the subassembly help file for that particular one – the help files for subassemblies are absolutely phenomenal.

Once my corridor is built, I build two surfaces from my corridor. My first surface is the roadway top surface – that’s the one that I want to show contours for in my finished plan, and is built from the Top link. My second surface is what I consider to be my working surface, and is called my roadway datum surface. It is calculated from the very bottom (or datum) of my corridor and is used for earthwork quantities. To make the quantities more accurate, I also create a boundary around both surfaces, typically from the Daylight feature line.

Once my surfaces are created, I create my sample line group (SLG.) In that SLG, I sample 4 items: my existing ground surface, my corridor top surface, my corridor datum surface, and my corridor itself. All of the typical styles are applied with one exception – I don’t want to see my datum line, so I assign it a null style.


Next, I create my sample lines as I normally do, and may even create some section views to see what’s going on. Once that’s done, I compute materials using the Earthworks criteria. I specify my EG as the existing ground, and my corridor datum surface as the datum surface, as shown below:


Once that’s done, I simply click OK. I’m done, right?   Well, no, there’s other stuff to add, but I can’t do it there. What I have to do now is go right back into that same command. There’s no “edit materials list” command, but using the Compute Materials command on the same SLG brings up a window that lets us either edit our current materials or add new ones. Well, that sound like what we want to do, so let’s look at that dialog box:


This allows me to change the cut and fill factors for my soil shrinkage and expansion, and a nice shiny button in the upper left allows me to add new materials. If I change my Data Types from Surface to Corridor Shapes, you can see the different materials available for materials display:


If I want quantities of each material in my corridor, I simply have to add each one as a new material in my list. The problem is that if I click the Add New Material button and then try to add a corridor shape, I get this nice error message:


This one threw me a bit until I looked at the new material and saw that the material type was set to cut. If I click in that box, I get a pulldown that allows me to select Structures, as shown below:


Once I select the Material Quantity Type as Structures, I can then go and add each one, remembering to change the name of each material for easy sorting later.


Now that I’ve done that, I can go create my material tables. The first one will be a total earthworks table, and then one for each of my corridor materials.


So I hope that de-mystifies the secrets of quantities. There are a few nuances to remember, and know that your corridor has to be modeled correctly before you can calculate quantities with any form of accuracy.  

Have fun!


  1. A good way to check your sections before you do your quantity calc’s is to apply the material shape; this way you will see if there is anything out of order.

    I like to make the material shapes a light colored hatch and send them to the back. When you are done with the shapes change them to a ‘no display’ style.

  2. Bill Neuhauser says:

    Wouldn’t it be nice if Civil 3D did real world quantities and not just C.Y. ?

    i.e. L.F. of curb and gutter, or how about s.y. of asphalt….. of s.y. of sidewalk etc.

    Isn’t about time we get real quantities that we can use other than Cubic Yards of curb….

    Just a major wish of mine for the past ten years or so… the hours I have wasted doing quantities by hand or by listing a polyline….

  3. John Mayo says:


    Happy New Year and thanks for this post. The timing is perfect as I am updating our templates with codes sets.

    I have this all set up great but I am left asking how do you deal with no materials showing up on cul-de-sacs & intersections where the corridor baseline is the BC & not the crown?

    John Mayo

  4. Jason Hickey says:

    Hi John –

    For those “other” areas of the corridor (which I agree aren’t very well addressed with respect to sections) I think I would still sample the areas with sample lines around the BOC, EOP, whatever, just not show the sections (they’re useless for my purposes.) But you can still calculate quantities off of them, even if they’re ugly.

    As far as a true BOM, there are programs out there that do true construction estimating, and Civil 3D isn’t one of them. I personally think that there are many many other things that need to be added/fixed before the developers step off into that pool.

  5. John Mayo says:

    Got it. Thanks again.


  6. Jason,

    Can you post up the dwg that data came from? Just curious.

  7. Jason,
    I totally disagree with you about C3D not needing to address the BOM (Bill of Materials) question. This is one of if not the biggest stepping stones they have to cross if they truly want to get into the DOT’s doors! Their software does it now and has for many years! And whenever we bring up C3D to them they throw the BOM question at us and we go, ya we know what you are talking about but no our software can’t do it yet. ;( Until it does I don’t even waste my time anymore with companies that use Geopak. We have no answer for them yet! So this is a big huddle that needs to be addressed! I have been asking for this for the past ten years!

    When you rally think about it? What do we really need to get from our design?

    1.) Plans (C3D has this covered now)
    2.) Quantities (Not even close! When was the last time you did a bid tab and paid for Curb in C.Y.? Never!

    Really that is what we are really aiming for! Paper, we are in the job of killing trees! Our customers really just care about the quantities because this is how they figure out what it is going to cost them!

    Thanks for reading!
    Bill Neuhauser P.E.

    p.s. Great web site guys, keep up the good work!

  8. Jason Hickey says:

    You know Bill, I’ve heard you ask for a BOM for a long long time, and to be quite honest, you’re the only person I’ve ever heard ask for it. You mention quite frequently that people ask you daily (or weekly, or whatever) but I have yet to hear a client request it. Maybe it’s something big in your area, but I think it’s not that big of a deal for the majority of users – if Geopak does quantities that well and that’s the requirement, then I think that’s what that client should use.

    I’ve stated it once, and I’ll stand by that statement – Civil 3D is a design tool, not an estimating tool – most of my designers run quantities, but for the really close estimating, the contratctor does that with some very specialized and expensive software. Apparently, Geopak has figured out both, but I think there are things that are much more important to most users that should be concentrated on first with Civil 3D.

  9. Darcy Farris says:

    Like making sure all the Help buttons work?

    I think Bill has a good point, however I would think that you could come up with a lisp or something that would calculate curbing in linear feet. Generally your curbing follows your alignments right? In this case you would need a lisp to calc the lf of the alignment(s) which are related to curbing in your corridor. I’m no programmer. I know squat about lisp, but surely it can be done. I’ve seen people do some pretty amazing things with it.

  10. There are a number of LSPS out there that follow lines, add up lengths, etc. I just don’t see the requests for BOM from many clients. I’d go so far as to say that for 3/4 of the civil market, TIN volumes is all they are after from the app. They don’t even care about the quantities available with the corridor as it is now.

    Sure, it would be nice to have quantities that match the bid tab, but I’d rather have structures that calculate bypass, or commas in lengths, or any number of other things before I’d get wound up about the LF feet of C&G. Especially since that would require a new level of modeling detail that would solve only that purpose.

  11. Just ask you local DOT using Geopak how important BOM is to them! This is a large thorn in C3Ds side with the DOT’s, it is a function their software does now and ours doesn’t and therefore one more feather in there hair that we do not have.

    Maybe your customers never request it because they have never seen something like it before? Maybe they have never been exposed to Geopak. In your next essentials class mention BOM and C3D and see what kind of reaction you get? You might be surprised!

    I don’t know how you and your customers now come up with quantities (accurate and fast), but I do know that my customers do waste a lot of time adding up simple things like Curb and Gutter, asphalt etc that C3D and LDT do nothing for. This should be really easy with corridors and feature lines!

    I just wish I knew how to program in .net or .xml, FORTRAN was the program during my day in school and what a waste of a quarter that was! Maybe you guys could aim me toward a good book on this?

  12. Darcy Farris says:

    It would be useful for us on our city roadway work as well. The cost estimates are structured much like the DOT’s.

    James, would it be possible to run a Map query on the corridor/feature lines linework for the curbing to get this sort of data?

    I know if you were dealing with simple AutoCAD lines and such you could run a report query to get lengths of curbing, etc.

  13. Jason Hickey says:

    Darcy – no, it would not be possible to run a Map query, since the corridor/feature line is a Civil 3D object, and Map doesn’t read Civil 3D objects at all (but that’s a discussion for another day.) That’s why James said it would involve a whole new level of modeling just to help that one issue.

  14. Darcy Farris says:

    Ah that’s right. I hadn’t thought of that. You could do it using your primary AutoCAD linework though so long as it is layered properly and it wouldn’t be all that difficult. Just be sure to retain the original objects when creating feature lines. It may not be the most efficient way to go about it, but hey, beggars can’t be choosers.

  15. Scott Creten says:

    I second the requests by Bill and Darcy. I think Civil 3D would be an incredible tool for road and highway design (including plan production) with a few more tweaks. I think Autodesk could take over the DOT market if they wanted to if they just talked with the DOT’s on exactly what they need out of the software, and then get it programmed into the software. If Geopak can do it now, I’m sure it would be no problem to implement the logic into Civil 3D as well.