As a subcontractor, you may wonder if you can leverage drone technology in your current workflow. The answer is – Yes. Let’s look at how and where it makes sense. Drones can provide meaningful data throughout the entire process – from concept through completion.
Many firms are discovering that outsourcing or subcontracting drone technology, saves them time and money on all kinds of projects. While drone technology is safe, scalable, and easy to integrate into current workflows, subcontracting leaves the regulatory and maintenance matters to a specialized professional.
Here are some ideas for integration:
- Site selection
- Mapping (photomosaic)
- Feasibility studies
- Determining or verifying view corridors
- Shooting still and moving images for promotional uses
- Following the grading process
- Tracking cut and fill
- Volume calculations
- Creating point clouds and DTM’s
- Verifying the construction process, (i.e. “Was all the rebar placed correctly?”)
- and the list goes on and on.
A Single Source of Truth
For now, let’s focus on a high-level concept drones can provide that speaks to the above list. A Single Source of Truth. What do we mean by a single source of truth?
Achieving a single source of truth means being able to operate at an enterprise-level, system-wide, cross-platform, and cross-discipline by sharing the data most recently collected from the field as a foundational source. Or put more simply, all the stakeholders on the project know the exact current state of the project. The benefits are realized in saving time, scheduling, ordering, waste control, conflict resolution, expediting RFIs, safety, and more. The drone imagery also creates a historical record that can be used for verifications, if required.
Does this sound like a monumental task? It really isn’t. And the best part is having a single source of truth that is scalable along with the scope of a project. Drone technology can be implemented at a base subcontractor level for the entire project, or simply on demand when needed. Some firms require daily flights while others only need one or two flights for the entire project. The level of integration is dictated by the project itself.
The collected imagery and data processed create one undeniable source of truth where all stakeholders are assured of the current state of the project. Are the teams on schedule? Do RFIs get back to the field in time to avoid timeline delays? Is everyone communicating? You can have these answers, many times, before they become questions.
So, how can you achieve the project “truth”? We use a process called photogrammetry.
The Photogrammetry Process
Wikipedia defines photogrammetry as “the science of making measurements from photographs, especially for recovering the exact position of surface points. Photogrammetry is as old as modern photography, dating to the mid-19th century and in the simplest example, the distance between two points that lie on a plane parallel to the photographic image plane, can be determined by measuring their distance on the image, if the scale of the image is known.”
Drones are the perfect tool to accomplish photogrammetry, using GPS, and known points on the ground called Ground Control Points (GCP). The drone flies in a precise pattern and altitude while taking hundreds, and sometimes more than a thousand photographs.
Next, the imagery is coordinated using the photographic metadata and the GPCs in post flight processing to create a point cloud. While it is possible to work directly from the point cloud (delivered in .rcs or .las formats), you can also produce other formats that many clients find more usable including.
The additional formats include:
- 2D Orthomosaic (.tiff) a flatten 2D image that is created from the photographs and is stitched together by referencing the point cloud making it scalable and able to be used as a background image. These are high resolution aerial images.
- Digital Terrain Model, DTM (.tiff)
- Digital Elevation Model, DEM (.tiff)
- Contour Model (.shp, .dxf)
- 3D Mesh (.rcm, .obj)
- Even native AutoCAD and Revit files where you can start your design work.
Again, the project drives the technology and the information needs. Using an outside subcontractor relieves you of the burden of technology investment, education, certification, and most notably the liability. It is important, however, to verify the subcontractor you choose is licensed and knowledgeable of the construction industry as well as compliant with local and federal flight laws.
Once the site has been scanned, you have a digital twin of reality – in this case, the truth of the project at a point in time. And, by sharing the digital twin with your project team and stakeholders, everyone is working with the same reality. Consider the effect on weekly team meetings where the exact site image can achieve faster solutions and reduce disputes.
How do you get started? Compare your current process for capturing existing conditions to one using a drone subcontractor. You will find you can receive the data faster and eliminate return site visits as the project begins. The progress reports provided by drone imagery are especially useful for tracking project milestones and more.
A single source of truth – the drone way.
David Dengler is a licensed FAA 107 UAV / UAS (drone) pilot and AEC Specialist at Kelar Pacific, LLC. Kelar Pacific provides technology services, software, and training for the architecture, engineering, and construction (AEC) industry. Specialties include 3D laser scanning, drone photogrammetry, robotic station point layout, BIM modeling and coordination and 4D pursuit videos. Kelar Pacific is a Gold Partner for Autodesk and Bluebeam products. Additional products and consulting include Primavera, Sage, Procore, BIMTrack, Strucsoft, and Fuzor (VR). For more information visit www.kelarpacific.com or call 800-578-2457.
