How to calculate quantity takeoff in Civil 3D

Quantity takeoffs calculation lays the groundwork for accurate cost estimations and resource allocations.

At its core, a quantity takeoff involves calculating the quantities of materials needed for construction based on project blueprints and specifications, with as little room for error as possible.

These materials can include earthwork, concrete, asphalt, steel, and more.

Accurate quantity takeoffs are crucial for budgeting, bidding, and scheduling purposes, ensuring that your projects proceed smoothly within predefined parameters.

So, in this comprehensive article, we will dive into the particulars of creating precise quantity takeoffs using Civil 3D, utilizing an existing sample road construction project as our guiding example.

We have also explained all about quantity take off in a step by step way with several examples in our AutoCAD Civil 3D course.

Starting with a sample project

Before starting the quantity take-off process, it’s essential to develop a comprehensive 3D model of the road project.

This model should accurately represent the design intent, including alignments, profiles, corridors, and other relevant elements.

In this case, you can follow along by downloading the Civil 3D file used in this tutorial here.

Defining sub assemblies

From the lesson files open the “Quantity takeoff Civil 3D undone.dwg” file which looks like the following image. 

Here we need to start by defining the sub-assemblies, sub-assemblies play a pivotal role in your Civil 3D’s quantity take-off process.

These pre-defined components represent various road elements such as lanes, shoulders, curbs, and sidewalks.

Utilizing sub-assemblies ensures consistency and accuracy in quantity calculations, as each component’s properties are predefined.

To get your sub-assemblies, you first need to create an “Assembly”.

Start by going to the Home tab, navigate to the “Create Design” panel and select the “Create Assembly” option.

Once you click on it, the “Create Assembly” menu will pop up where you will give the name, description (optional), type, style, layer, and code set for your assembly.

In this case, update the information as illustrated below, then click on “OK”.

Then the Civil 3D software will ask you to specify the assembly’s baseline location.

In this case, specify anywhere you prefer but away from your model so as not to create overlapping of items.

Once you click at your preferred location, in this case, it is placed at the coordinate as indicated below, the assembly symbol will be shown on your model space as shown below.

Now you need to define your sub-assemblies (curbs, drains, pavement details, etc.) and their parameters, depending on your design considerations and standards.

To define them, navigate to the Home tab, under the palettes, and activate the “Tool palettes.”

Once active, the palette window will pop up from where you can choose the specific sub-assembly you require from the available tabs, as illustrated below:

Once you click on any of your preferred sub-assemblies, the properties palette will pop up and you can alter the parameters for each sub assembly under the “Advanced” section depending on your design and project specifications.

For our example though, I will leave all the parameters as default.

In this case, I will be using three main types of sub-assemblies: lanes, curbs, and trench pipes.

To place the lane sub-assembly (1), navigate to the lanes tab, then select "LavesuperelevationAOR, and once active, you will have to select the assembly, and automatically the lane layer will be attached to it.

For the curb sub-assembly (2), click on the curbs tab, select "UrbanCurbGutterGeneral, and then click on the top right lane ring to attach your curb.

For the ditch sub-assembly (3), click on the trench pipe tab, select "SideDitchwithLid,” and click on the top left lane ring to attach your drain as illustrated below.

Creating the corridor

Corridors in Civil 3D represent the design cross-section of the road project.

By defining the corridor parameters and assigning appropriate sub-assemblies, engineers can generate a dynamic representation of the road's geometry, facilitating the extraction of quantities.

To access this command, navigate to the corridor command under the Home tab, and once the command is active, the “Create Corridor” menu will pop up.

Now you will have to specify the horizontal alignment and the vertical profile.

In this case, update the parameters within the “Create Corridor” window as follows:

• Name: SourceCAD Corridor

• Code style: Basic

• Alignment: Project Road Alignment

• Profile: Existing Surface - Surface 2

• Assembly: Main Road Assembly

• Target surface: Existing Surface

Finally, uncheck the “Set baseline and region parameters” then click OK.

Civil 3D will generate a corridor with the set parameters as illustrated below:

After generating your corridor, left-click on it to select it.

The Corridor contextual ribbon will be shown from where you can modify more parameters on the corridor, in this case, click on “Corridor Properties”.

Once selected, the “Corridor Properties” window for that specific corridor will pop up.

Navigate to the “Surface” tab from where you will create your corridor surfaces.

First, click on the “Create a corridor surface” icon, and the corridor surface shell will be added to the display list.

You can rename the shell to “Top” then under the “Add data” section, specify your data as “Links” and the specification code as “Top” then click on the “+” icon to add it under the “Top” corridor surface.

Then check the box for “Set as breakline" then repeat the same for the “Datum” surface as well, as shown below.

Creating Sample Lines

Before generating your quantities, Civil 3D software needs to be guided using sectioning’s on the points it needs to sample and analyze the data, which is where sample lines come in.

To access this option, navigate to the Home tab, under “Profile & Section Views,” and select the sample line command.

Once the command is active, Civil 3D will prompt you to select an Alignment within your model either by clicking on it or by pressing the “Enter” key on your keyboard and selecting the alignment of your choice from the available list.

In this case, press on Enter, select the “Proposed Road Centerline” from the list, and then press on “OK.”

Once you press “OK” the “Create Sample Line Group” window will pop up, under which you can specify some parameters.

But for this case, just update the name to “SourceCAD SL,” and leave the other items in default as shown below, and click on “OK”.

Once that is done, you will be in the “Sample Line Tool” which will be active.

Before pressing anything within your model, first change the sample line creation to “By Range of Stations” and by selecting that option, the “Create Sample Lines -By Station Range” contextual window will pop up.

Press “OK” then press your ESC key to exit from the sample line command completely.

Quantity Take-Off Tools

Civil 3D offers a suite of tools specifically designed for quantity take-offs.

These tools enable engineers to extract quantities directly from the corridor model, including earthwork volumes, material quantities, and surface areas.

To access some of these tools, click on any of the generated sample lines to activate the contextual ribbon, from which you have the option of “Compute Materials,” click on it to activate it.

Civil 3D will prompt you to select the Alignment and the Sample line group to use for the computation.

In this case, select as shown below, and press “OK” to activate the “Compute Material” window.

In this window, change your “Quantity Take Off” criteria to “Earthworks”.

Under the Volume calculation method, select “Average End Area”.

Under the display list, click on “<Click here…>” to specify your object name in the “Name in Criteria” panel and then leave the other parameters as shown below.

Finally click on “OK” to close the command window.

Generating Volume Report in Civil 3D

So the last item that remains is to review the extracted quantities to ensure accuracy and completeness.

Still, under the Sample Line Group contextual ribbon, you can access the “Generating Volume Report” command.

Alternatively, the same command can be found within the “Volume and Materials” panel in the “Analyze” tab.

Once you click on the command, the “Report Quantities” window will pop up, where you need to pick the alignment, sample line group, material list, and sheet style set.

In this case, specify the “Proposed Road Alignment” to be your Alignment, the sample line group to be “SourceCAD SL” the material list to “Material List (1)” and the sheet style set to be “Earthworks" then press OK as illustrated below.

You can also choose to represent the volume report within your model space as a table.

To do that simply click on the “Total Volume Report Table” within the “Volumes and Materials” Panel found under the “Analyze” tab, or from the sample line group contextual ribbon.

Once the command is activated, the “Create Total Volume Report Table” window will pop up, where you can specify the following parameters.

Table style as “Cut and Fill” the “Proposed Road Alignment” to be your alignment, the sample line group to be “SourceCAD SL,” the material list to be “Material List (1),” and leave the rest as shown below.

Then press OK and specify the placement location within your workspace.

Even better, if you want to export your report in a format that can be opened with Microsoft applications, such as Word or even Excel, it's possible.

Navigate to the “Toolbox” tab found within the “Toolspace” Palette.

Expand the “Reports Manager” tree to find “Corridors” expand it to find the “Volume Report” right-click on it to find the "execute" command.

Once the command is active, a pop-up will be shown stating that “No sample line group available in selected alignment” Simply click on OK to access the “Create Report” menu.

Under it, specify the Alignment as the “Proposed Road Alignment” and all the other criteria will be updated accordingly.

Under the “Save Report to:” section, click on the folder icon where you will not only specify the location to save your report but also the file format that in which you will be saving it.

In this case we are saving it in “XML” Excel format.

Once you are done, click on the “Create Report” command, and the report will be generated and launched.

You can then click on “Done” to close the window.

Frequently asked question

Here are some questions that we get quite frequently related to calculating quantity takeoff in Civil 3D.

Why is my volume data empty in the Earthwork report?

This situation occurs if the resources available within your model are not being fully utilized.

To fix this problem click on any of your sample lines within the existing Sample Line groups to activate the contextual window.

Within the contextual window, under the “Modify” panel, click on the “Sample More Resources” command, and the “Section Resource” menu will pop up.

Under “Available Resources” select the item, click on the “Add>>” icon, and the item will be transferred to the “Sampled resources:” display list as shown below, then click OK to save changes.

If you run your “Volume Report” again, the data will be captured as needed.

Is it possible to generate quantity takeoff for Materials like Curbs, Drains, Asphalt, etc?

Yes, it is possible to use Civil 3D to get a comprehensive report on the sub-assembly items like curbs, drains, lids, etc. used within your corridor.

Click on any of your sample lines within the existing Sample Line groups to activate the contextual window.

Within the contextual window, under the “Launch Pad” panel, click on the “Compute Materials” command, and the “Select a Sample Line Group” menu will pop up.

Click OK to access the “Edit Material List” menu.

On the bottom, right-hand corner, click on the “Import another criteria” option and the “Select a Quantity Takeoff Criteria” option will be shown.

Select the “Material List” from the drop-down list and press OK.

Afterward, the “Compute Materials” menu will pop up, and within the display list under the corridor shapes, specify the pavement material as “Pave1” base material as “Base” and Subbase material as “Subbase” then click OK.

Alternatively, to incorporate all the sub-assemblies present within the corridor, you can create a new “Quantity Takeoff Criteria” as shown below, then press OK.

Once the above steps are done, click the “Generate Volume Report” command under the “Launch Pad” panel within the Sample line contextual ribbon to launch the “Report Quantities” menu.

In this menu under the “Select material list:” you can select the newly created list.

In this case for “Pavement Materials” Change the style set to “Select Material” then click OK to view the report in HTML format.

This is how the final report will look like.

Summary

In conclusion, mastering quantity take-offs in Civil 3D is essential for efficient project management and cost estimation in road construction projects.

By understanding the core principles of sub-assembly utilization and leveraging Civil 3D's powerful tools, engineers can generate accurate quantity take-offs.

Finally, here we have collected some Civil 3D tips and tricks that I am sure will increase your productivity with the software.

Let me know in the comments down below if you have questions related to this article.