Customizing Leads to Productivity in Grading Projects
Did you know that we, as humans, move around seven gigatons of earth each year? That is a lot of dirt, and it takes a lot of money to move such massive volumes. Being able to move dirt virtually is very valuable and helps ensure that the project will work within budget before ever breaking ground. Whether you are doing a residential or commercial site plan, designing a subway, or constructing a large dam, AutoCAD® Civil 3D® makes grading virtually easy.
AutoCAD Civil 3D is a powerful grading tool. The dynamic 3D model that it creates provides a way to see the final project and estimate earth volumes quickly and accurately. I have some bad news and some good news around this subject. The bad news is, the software does need to be set up to make the grading visualization easier. The good news is, set up is quick and easy. In this article, I share with you how I like to customize AutoCAD Civil 3D to make grading easier.
Working with Slope Arrows
Slope arrows provide visual clues indicating which direction water will run on a site. Creating a surface style with slope arrows turned on makes it very clear whether or not the site will drain in the intended direction. In Figure 1, it is clear that the water will drain away from the building footprint, to the front and back of lot five.
Figure 1: Surface with Slope Arrows turned on
To create the surface style required, go to the setting tab of the Toolspace. Expand the Surfaces category, right-click on Surface Styles, and select New. In the Information tab, type a name that is relevant for your needs. I typically name this style “Grading” to help me remember to use it when I am creating my grading plan. On the Display tab, turn on all the components you would like to see displayed in the model. I recommend turning on at least the major and minor contours and the slope arrows, as shown in Figure 2.
Figure 2: Grading Surface Style
Note that the layer next to the Slope Arrows component is grayed out. This means that you cannot change the layer to which they default. You also cannot change the color of the arrows on the Display tab. You can, however, change the color scheme for the arrows on the Analysis tab of the Surface Style dialog box, as shown in Figure 3.
Figure 3: Analysis tab of the Surface Style dialog box
Once the style is set up, it is just a matter of using it. Of course, you do not want to use it at all times. For instance, you are not likely going to want to print the plan with all those arrows displayed. That is why it is important to have multiple surface styles created. Then select the style to be used in the surface properties for various tasks.
If selecting the surface and clicking the Surface Properties on the contextual ribbon is too much of a hassle, there is a faster way to change the style being used by a surface. If you are fortunate enough to have two monitors, then keeping the Properties palette open on the second screen can make switching between object styles extremely quick and easy. If you do not have two monitors, then you may want to use Quick Properties instead of the Properties palette. Either way, when you select the surface in the model, the current style name appears in the Style field of the Properties palette and Quick Properties, as shown in Figure 4. Simply click inside the Style field and select an available style from the drop-down list to switch between styles.
Figure 4: Properties palette and Quick Properties
Take Advantage of Volume Surfaces
Balancing cut and fill quantities plays a key role in keeping a project within budget. Although grading groups have the option to balance cut and fill, it is more likely that the entire project site needs to be balanced, not just one area. That is why Autodesk has provided tools for checking the volume between two surfaces. The Volumes Dashboard found on the Analyze tab, Volumes and Materials panel provides a quick volume calculation between two surfaces. It does this by creating a volume surface. Once created, the volume of cut and fill appears in the Volumes Dashboard. Both a cut and fill factor can be entered to accommodate the swell factor and compaction rate of the soil for the site, as shown in Figure 5. Scrolling to the right inside the Volumes Dashboard provides a net cut/fill between the surfaces.
Figure 5: Volumes dashboard
In addition to the Volumes Dashboard, the properties of the volume surface also provide a way to view the cut and fill volumes between the base and comparison surfaces. Because it is part of the properties of the surface, a surface table can be created that shows the volume of the cut and fill along with the area for each. In order to make the table appear properly with values appearing in it, the default table needs to be altered and the volume surface needs to have an analysis done on it.
Setting Up the Volume Surface Table
A volume surface basically calculates the difference in elevation between two surfaces. Therefore, it is easier to start with the default Elevation Table that ships with the software to set up the volume surface table. In the Settings tab of the Toolspace, expand the Surface category, Table Styles, Elevation. Right-click on the Elevations table style and select Copy.
1.On the Information tab, type Cut-Fill Volumes in the name field.
2.In the Data Properties tab, click the plus symbol to add a new column to the table.
3.In the new column, double-click the header to add a column title.
4.In the new column, double-click the Column Value field to add the Surface Range Volume property to the table, as shown in Figure 6.
Figure 6: Table contents
Populating the Volume Surface Table
Once the table style is created, you can create a table for the surface. However, the table values will be empty until you complete an elevation analysis on the volume surface. We will start by adding a table to the model. It does not matter which you do first as long as the table is dynamic.
How to Create the Right Table:
1.On the Annotate tab, Labels & Tables panel, click Add Tables and select Add Surface Legend Table.
2.Press <Enter> to select a surface from the Select a Surface dialog box.
3.In the Select a Surface dialog box, select the volume surface created earlier and click OK.
4.In the command line, select Elevations.
5.In the command line, select Dynamic.
6.In the model, click to place the upper left corner of the table.
How to Populate the Surface Volume Table Values:
1.In the Prospector tab of the Toolspace, expand the Surfaces category.
2.Right-click on the Volume Surface you just created the table for and select Surface Properties.
3.In the Surface Properties dialog box, on the Analysis tab, set the Analysis type to Elevations and set the Number of ranges to 2. Then run the analysis.
4.Set the Maximum Elevation for the first range to 0 and set the color to Red for Cut areas.
5.Set the Minimum Elevation for the second range to 0 and set the color to Blue for Fill areas, as shown in Figure 7.
6.When you click OK, the Volume Surface Table should automatically update.
Figure 7: Surface analysis
Note: More ranges can be set up as needed to show where higher volumes of cut/fill are happening on the site.
Displaying Cut/Fill Contours
In order to clearly differentiate the cut areas from the fill areas, a surface style must be created and applied to the surface after an analysis is done. The templates that ship with the software already have a surface style—Cut and Fill Banding 1 Interval (2D)—that can be used. However, most companies are using their own templates and may have purged this style out when they created the company standard. If this is the case for you, it is easy to recreate the style.
1.In the Settings tab of the Toolspace, expand the Surface category, right-click on Surface Styles, and select New.
2.In the Surface Style dialog box on the Information tab, type a relevant name (such as Cut-Fill Banding, for example).
3.On the Display tab, make sure that Elevations are turned on. You can also turn on the major and minor contours if you wish to see where various areas have more cut or fill depths.
4.If you turned on the contours in the Display tab, then also set the Contour Intervals on the Contours tab, as shown in Figure 8.
5.If contours are being displayed, you can now label the contours. The label text that appears is actually the depth of the earth between the base and comparison surfaces.
Figure 8: Set contour intervals
Using slope arrows and volume surfaces in conjunction with each other as you create grading plans can help you verify quickly and easily that the project is draining properly. It also helps you ensure that the project stays within budget by allowing you to see exactly how much cut and fill is happening across the entire site. Until next time, good luck and happy grading!
