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For designers and engineers, the ability to seamlessly combine drone data with their existing CAD capabilities has meant faster, more efficient workflows. Planning earthwork for land development and roadway design projects, developing community masterplans, and performing material takeoffs has been made easier thanks to advances in drone surveying software.
Autodesk Civil 3D is a common CAD software used for civil infrastructure design and documentation—and one that’s particularly easy to use alongside drone data platforms. Below, we walk through the five most common Civil 3D workflows that you need to know if you’re going to integrate drone data into your CAD work.
Orthophotos are 2D aerial images that have been created by stitching together hundreds of individual drone photos and rectifying for angle and distortion. Orthophotos in DWG files are frequently used by engineers and land developers to generate planning documents, such as masterplans, subdivision phasing plans, and zoning exhibits.
They also aid in development of civil designs for a variety of projects. A model can be loaded on top of an orthophoto in Civil 3D. Here’s how to upload an orthophoto:
If uploading a JPEG, two additional files will be downloaded: a WLD and JGW. These need to remain in the same folder as the JPEG to enable Civil 3D to correctly insert the orthophoto. To make sure Civil 3D is able to read the WLD file, check the Modify Correlation. This will pull up the Image Correlation when you upload your file, where you can verify that the Correlation Source is set to World File.
5. Save your drawing.
Instead of exporting survey data to use in Civil 3D, you might choose to take the opposite approach: importing design files and final grade surfaces to a drone data platform.
The advantage of this is that you only have to upload those design files once (until inevitably your design changes). As you add more surveys to your drone software over time, you can then measure your progress against those designs.
Because .DWG files are interoperable with few non-CAD programs, you’ll need to convert your design files into DXFs before you can export them from Civil 3D.
This will make it so that the model is only displayed as triangles in model space.
Some drone software is capable of visualizing your site as a 3D model, which you can export as a TIN surface to use in Civil 3D. In the reverse of the previous workflow, doing this will require you to convert a DXF file into a TIN surface Civil 3D will recognize.
(The 3D faces will automatically be set to layer 0. It’s recommended, but not mandatory, to create a new layer and assign the 3D faces to that.)
If that’s the case, right-click the surface, and select Edit Surface Style. In the dialog box, navigate to the Display tab. All the attributes associated with the TIN surface can be toggled on and off, including major and minor contours, triangles, and the border.
Whichever drone surveying platform you work with, there will be a limit on the size of the TIN surface you can upload. The size of a TIN is measured in the number of triangles, or 3D faces. , This workflow will outline how to reduce the number of triangles in a TIN surface so that you can upload it to your drone data software of choice as a DXF.
Right-click on the surface name and select Surface Properties.
In the Statistics tab of the dialog box, expand the TIN category to see the number of triangles (3D faces) the TIN surface contains. If the number is above the acceptable triangle limit for your drone survey software of choice, continue with this workflow.
In the dialogue box, select Edge Contraction and click Next.
In the second dialog box, confirm that your region is set to Use existing surface border and click Next.
In the final dialog box, you’ll specify what percentage of triangles you need to remove from the TIN surface to get to an acceptable amount for your drone survey software. (Make sure to check the box next to Percentage of points to remove.)
Enter a percent to remove and the dialog box will calculate how many triangles the TIN will have left. Hit Apply once you’ve determined the correct percent to remove.
(If the number of triangles are not reduced enough, go to the Prospector tab of your Toolspace and navigate to Surfaces > [the name of your surface] > Definition > Edits A list of edits will appear below the Toolspace palette. Delete the Simplify Surface edit and repeat Step 3.
NOTE: Surfaces created or modified by adding drawing objects like feature lines, contours, points or 3D faces will need to be exported as a LandXML file and imported back into a clean drawing in Civil 3D. TIN surfaces with drawing objects attached are not able to be simplified.
You can easily export your surface to an XML file by navigating to the Prospector tab in the Toolspace, expanding the surfaces category, right-clicking on the surface name and selecting Export LandXML. To import an XML file into Civil 3D, enter the command “XMLIN” and navigate to the folder containing the XML file.
Utility strikes are inconvenient, costly mistakes that every contractor tries to avoid. The easiest way to do this is to maintain visibility on the utility line work beneath the surface on your site. Here, we’ll walk you through creating a pipe network DXF file in Civil 3D, which can be used alongside your survey data.
In the dialog box, set the Mesh type to Triangle. You can change the Mesh distance to adjust the density of the mesh, if desired.
Now that you understand how drone surveying and Civil 3D can be used together to improve construction workflows, take a look at how drone data software works with your surface design files:
Civil 3D design and documentation is only one of many use cases for drones in construction. As drone surveying continues to become more commonplace on construction and civil engineering projects, the accessibility and usefulness of drone data has improved along with it.
User-friendly, interactive drone surveying platforms are being used by personnel at all levels—from GIS specialists and construction surveyors to on-site managers—to map, measure, and uncover critical insights about their worksites.
Want to see how else drone data can be used to improve your workflows? Check out our FREE ebook, From Surveyor to Home Office: How Up-to-Date Construction Data is Improving Worksite Operations
Keep reading:
Calculating Cut and Fill Quantities On Your Construction Site
What are DXF Files and How are They Used in Drone Surveying?
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