So, in class last week, I had some folks that work in the mining industry and they needed to create a filling curve. What’s a filling curve you ask? Well, you know what the final grade is going to be but, how much volume material have you placed in this area once it reaches a specific elevation, well, that’s a filling curve.

I was racking my brain on how to do this. An elevation analysis didn’t work on the volume surface because that gave me the depth of fill, not the elevation of fill. With the new Volumes Dashboard Extension available through the subscription website, I came up with a solution. Now, this won’t actually plot a curve for you but it will compute the volumes at any elevation for you.

To start off with, you need two surface, 1) the existing ground and 2) the filled in surface (in this example, I’ll refer to them as EG and Fill Stack). In order for this to work, the existing ground must be trimmed out to the exact limits of the proposed ground so extract the border from the proposed ground and use it as a boundary in the existing ground (I would recommend creating a new surface, pasting the original EG into it and applying the boundary to that rather then modifying the original EG).

Just so you can see what is going on, here is a cross section across  the site.

EG and Filling Surfaces

As you can see, the existing ground varies quite a bit so it’s important to take that into consideration. What we need to do now is create a flat surface that represents the elevation that we have filled. Simple, create a rectangle, assign it the elevation you want, and add it to a knew surface (I’ll refer to this one as the Level surface). Now we can see this new surface in our cross section.

EG, Filling and Level Surfaces

The desired volume at this particular station is between three surfaces, the EG, the Fill Stack, and the Level surfaces. The volume we require is shown below but I can’t get that from comparing only two surface, I need to compare all three surfaces.

Required Volumes

I can calculate the fill between the Level surface and the Fill Stack surface

Fill Area comparing Level Surface to Fill Stack

And I can calculate the cut between the EG surface and the Level surface

Cut Area comparing EG Surface to Level Surface

You might have noticed that the required volume we need is the green fill area subtracted from the red cut area, and this is where the magic begins. Launch the Volumes Dashboard (it’s an extension if you are still using 2012 and, if history repeats itself, it’ll probably be incorporated into 2013 or whatever the next release will be) and create the two volumes surfaces that will result in the above cut and fill. The first Volume Surface I’ll create will have a base surface as the Fill Stack surface and the comparison surface of the Level surface (this one will be called Fill to Level) and the second Volume Surface I’ll create will have a base surface as the Level surface and the comparison surface of the EG surface (This one I’ll call Level to EG).

Volume Surfaces in the Dashboard

Unfortunately, right now, the numbers you are seeing aren’t correct. The reason for this is because the volumes surfaces are still taking into account the volume above the Level surface, I only want it to take into account the volume below the Level surface.

Volume Error

Well, the volume dashboard allows you to apply different cut and fill factors so, to prevent the volumes above the level surface from being used, simply set the cut or fill factor for that portion to zero.

Cut and Fill Factors Applied

Now simply move your Level surface up and down (grab the polyline and use the move command). If everything is set to “Rebuild Automatic” you’ll see these number automatically update. Now, there is no way that I’m aware of to take these number and have them automatically create a curve but you can have excel open on your other monitor and simply move the Level surface and type in the volume into Excel, repeat until you are done.

Now, you wouldn’t be keeping your license or job for long if you didn’t do some double checking so, how can you make sure the numbers you are seeing are correct? Well, create a new volume surface that compares the EG and the Fill Stack so you know what the total volume is and then move your Level surface above the highest elevation of your Fill Stack (the numbers should be the same) and then move your Level surface below the lowest elevation of your EG surface (the volume should be zero).

Maximum Fill Check

No Fill Check

One thing to make sure you do is to uncheck the volume surface you are using as the check so it’s not included in the totals on the left of the dashboard.

Hopefully you’ll start to see the value of using the volumes dashboard and some of the things you can do with it. The more I use it, the more I like it. If you come up with any other great ideas on how to use it, let me know and if they are awesome enough, I just might write a post about it and give you credit for it.

For more information on the Volumes Dashboard Extension, you can read about it HERE.


Just today I learned that there is a new tool up on Autodesk Labs called, “Project Silverstar”. The name means nothing to me but what this tool does is it will optimize your profile for you. Basically, you upload your existing ground profile and a series of offset profiles to the Autodesk Cloud, put in a few parameters, it chugs away in the “Cloud” and it returns to you the optimum profile for your alignment.

This is the first tool that I’m aware of that uses cloud computing to assist you in your design specifically for the Civil Engineering market from Autodesk. If you were at AU2011, I’m sure you’ve heard a lot about “The Cloud”, well, Civil 3D now has the power of the Cloud.

As I just heard about this tonight, I haven’t had a chance yet to really try it out. Look for a post next week to see my take on how well this tool works.

I love this time of year. The leaves are changing or already gone, I’m getting geared up for Autodesk University, and there are new tools being released for the software I know and love. On October 28th, Autodesk released a new tool for AutoCAD Civil 3D 2012 for their subscription customers called, “Volumes Dashboard Extension for Civil 3D 2012”. To get it, log onto the subscription site and choose “Access Your Subscription Benefits” then click on the Download link for your “Subscription Advantage Packs and other Autodesk product enhancements”.

I just downloaded it today and after playing around with it for a few minutes I can’t help but think to myself, this tool is great! I’ve often complained about the volume tools in Civil 3D how they aren’t permanent when you run them, they don’t create reports (you have to copy paste), and what’s up with that net graph thing at the end?

Current Volume Tools

To access the new tools (once you have installed them), go to the Toolbox on your Toolspace and expand out “Subscription Extension Manager”.  Double click on the tool and the new volume dashboard opens up in the same window (the Panorama) but it is new and cool and totally awesome!

New Volumes Dashboard

One of the nice things about this tool, is it allows you to work off volume surfaces so it’s permanent. In the old tools, once you calculated the volume and closed the tool, you lost your numbers. In this new tool, it’s simply pointing to your volume surfaces.

If you already have a volume surface in your drawing, you can add it to the list by using the first button along the top.

Add Volume Surface

If you haven’t created the volume surface yet, you can use this tool to create one for you. The second button on the list is where you will go for this.

Create a Volume Surface

Once the surfaces have been created and added to your dashboard, you will start to see the simple beauty of this tool. In this example I’ve added four different volume surfaces to the dashboard and it is revealing to me the total balance of the site (as you can see, I have a bit of cut going on here so far).

Surfaces Added to Dashboard

Now the fun begins. You can toggle on and off the different surfaces to be used in the calculation. In this case, I’m doing a bunch of excavating for the pond but, what about the roads? I need to know how much dirt I’m moving for them. Simply toggle off the surface for the pond and you’ll see the difference (I’m much closer to a balance point when you don’t take into consideration the pond).

Select only necessary surfaces

Now that we have the surfaces in the dashboard, perhaps you are only interested in the volume of a certain part of the project. In this case, I only want the west half of one of the roads. The third icon along the top will allow you make a bounded volume calculation. You need to have a polyline already in the drawing for this to work.

Adding a Bounded Volume

Have you ever had a site that had different cut and fill factors? A good example is structural back fill areas vs. landscaped areas. Well, you’ll love this tool because you can apply different factors to the different regions and it will total the volume up for you.

With a little bit of playing around, you can also add parcels as the boundary object. Select the area label of the parcel and it will add it. Honestly, I’m not sure I would use this option as parcels tend to be fleeting objects. Editing parcel segments has a tendency to remove and recreate parcels through the process. If a parcel is removed and then recreated, it will no longer act as a boundary to the surface. I’m not saying don’t use them, I’m just not sure yet. It’ll take a bit more investigation on my part.

Now that you have the volumes calculated, you can simply create a report for it. The sixth button along the top after the delete and recalculate buttons (those are pretty self explanatory) creates your report.

Generate Report

One of the nice things about this tool, it will only report on the surfaces or the bounded areas of the surfaces that you have selected. I created a report for the surfaces I’ve been using and I simply copied it from Internet Explorer and pasted it here:

Volume Summary
Name Type Cut Factor Fill Factor 2d Area(Sq. Ft.) Cut(Cu. Yd.) Fill(Cu. Yd.) Net(Cu. Yd.)
 Pond Volumes  full  1.000  1.000  235554.12  149245.67  898.02  +148347.66
 West Region of North Roadway  bounded  1.000  1.150  58491.59  1689.66  1407.99*  +281.67*
 East Region of North Roadway  bounded  1.000  1.230  93401.53  1203.19  3006.66*  -1803.47*
 Intersection  full  1.000  1.000  12031.25  0.00  4149.63  -4149.63
2d Area(Sq. Ft.) Cut(Cu. Yd.) Fill(Cu. Yd.) Net(Cu. Yd.)
 Total  399478.50  152138.52  9462.30*  +142676.23*
* Value adjusted by cut or fill factor other than 1.0

For my money, it doesn’t get much better than this. It’s super simple but amazingly powerful.

Note: After creating this post, I noticed the table is getting cut off due to width limitations in the blog. Here is a screen capture of the raw data of the report:

Report Output

Last, and certainly least (yes, you read that right, this is the least), you can place a summary of the volume calculations into your drawing.

Insert Volume Summary into Drawing

This will place a summary of the volumes into your drawing. Don’t get too excited, it doesn’t come in as a dynamic object like what we have all gotten used to in Civil 3D. In fact, it doesn’t even come in as an AutoCAD Table or even MTEXT. It comes in as an unnamed block. Explode the block and you get individual lines and pieces of text.

Cut/Fill Summary Exploded and Selected

I guess they thought they got away with this sort of thing with the QTO tools they could get away with it here. I’m really hoping this is just a temporary thing. Anyways, I’m glad they didn’t hold the tool back because they didn’t have a dynamic drawing label.

I hope you learned something new here and I hope this has encouraged you to go download this cool new tool. Have fun!

So, Rick over at Simply Civil 3D just posted about calculating volumes between two profiles. Now, there’s absolutely nothing wrong with the method he offered, I’m just going to offer a different solution.

Now, first off, you can’t calculate the volume between two profiles, Rick’s solution was to calculate the volume between two surfaces along an alignment and the two profiles are surface profiles of these two surfaces. You can calculate the area between two profiles but if all you have is profiles, you can’t calculate a volume. That being said, here is an alternative method to the problem.

Here’s the situation. I have an alignment and two surfaces and I want to know the volume between the two surfaces within 25′ of the alignment. Simply offset the alignment left and right 25′. When you offset an alignment, you’ll get a polyline. Draw line segments that close off the polyline and join it all into one closed polyline.

Next, we need to have something to calculate the volume from. Create a volume surface that uses the two surfaces that were used to create the profiles.  If you aren’t sure how to create a volume surface, click HERE. Once you have the volume surface created, you can calculate Bounded Volumes (Analyze Tab, Volumes and Materials Panel). It will ask you to select the volume surface and the bounding polyline and then will report the results at the command line. You can then copy and paste this as text into your drawing. The advantage to this method is it’s quick and easy to do. The advantage to Ricks method is the table that is created will dynamically update if the surfaces change and it will allow for the creation of a Mass Haul diagram.

Once again, I have another blog post that starts off with, “I’ve seen this crop up a lot lately…” This seems to be a recurring trend for this blog and, honestly, one I’m not intending to stop.

So, you are wanting to calculate the volume of a pond. You’re using Civil 3D and loving it and you start up the Stage Storage tool and then, it hits you. Which method do you use? The Average End Area Method or the Conic Approximation Method? Well, if there are two options in Civil 3D, most likely the answer is, “It depends”.

Volume Calculation Options

In my experience, the majority of people calculating storage volumes for a pond use the Average End Area Method because, well, isn’t that what we’ve always used for calculating volumes? And, in most cases, this is a great method for calculating volumes. So, how does the average end area work? Take the area at one section, add it to the area of the next section, divide that by 2, and then multiply by the distance between them.       [(A1+A2)/2]*D

What’s the problem with this method? Well, it’s a one dimensional equation. In other words, it works great when the areas change by getting wider OR by getting longer, but not both! A perfect example where this particular equation works great is calculating material volumes for roadway cross sections. The pavement between two cross sections may vary in width but, rarely does it vary in depth.

If you don’t believe me, try it yourself. In AutoCAD (you do have AutoCAD, don’t you?) draw a wedge. This is a perfect example of something that varies in one dimension between the two cross sections. The area of a wedge is [0.5 x base x width x height]. In other words, the average end area, one area being base x width and the other area being 0. For this example, I’ll use a base of 3′, a width of 4′, and a height of 5′; we get a volume of 30 cu. ft. (0.5x3x4x5=30).

Volume of a Wedge

If we take and modify this wedge slightly, invert it and give it a tapering along one axis (i.e. a pond with vertical sides north and south and sloped sides east and west), the same equation holds true.

Volume of a Portion of a Wedge

A1=4×1, A2=4X3; [(A1+A2)/2]*D;[(4+12)/2]*5=40.

Now, if we take these exact same lengths but change the wedge into a pyramid, the volumes are no longer valid. The volume of a pyramid is 1/3 x base x width x height and this is where we as engineers begin to over estimate the volume of ponds. What shape more closely represents the shape of your pond? Well, in most cases (definitely not all cases), it’s a pyramid, or at least a part of a pyramid.

Volume of a Pyramid

In geometric terms, a pyramid or cone with the top portion cut off is called a frustum. The volume of a frustum is h/3 x [b1 +b2 +sqrt(b1 x b2)] where h is the height between the two areas, and b1 and b2 are the areas of the two cross sections. This is what Civil 3D uses for the Conic Approximation method.

Examples of Geometric Frustums

Hopefully this will help you determine which method to use the next time you have to go about calculating volumes based of sections.

p.s. I probably got something wrong in this discussion. If you see any errors, please let me know.