A Higher Perspective On Drones at CSArch

Two years ago, I passed the Federal Aviation Administration (FAA) Part 107 Aeronautical Knowledge test to become a licensed commercial drone pilot. While licensure is a critical legal requirement to use drones at CSArch, it also provides a strong foundation to safely operate drones on project sites. 

Since getting my license, I have helped our designers get a better view of their projects by offering a birds-eye view from high above. Drones reduce the need to place our staff and resources in a position of risk and offer a rapid and economical way of acquiring data, images, and video. We are just realizing the benefits of drones in the design process at CSArch – here are a few ways drones are helping us.

Orthomosaic Maps

We use drones to create 2D orthomosaic maps to improve our building condition surveys, roof inspections, masonry evaluations, and building envelope analyses. Put simply, an orthomosaic map is a detailed, two-dimensional representation of an area, created from many photos that have been stitched together and geometrically corrected to accurately depict building conditions. This mapping technology allows us to perform a detailed roof inspection in less than an hour, whereas traditional methods can take a full day.

Before arriving on site, we program our drone to fly independently in a pre-determined flight pattern, which can be saved and replicated for another day. Think of this as an auto-pilot setting where the drone does all the flying for you. In the example below, our drone flew in a “lawnmower” pattern over a local high school capturing over 200 images. These images were stiched together to create a extremely detailed image of the roof. An immediate, real-time view of existing roof conditions is a significant improvement over Google Maps, where satellite images are outdated or taken in low-resolution. Repeatable, accurate flight control makes a drone the ideal tool for mapping a project site or even an entire campus. 

Elevation and Measurement

In addition to orthomosaic maps, drones provide us with other important data to evaluate roofing systems. Elevation layers allow us to view the elevation of the roof by using digital surface models (DSM) for buildings and digital terrain models (DTM) for landscape. Digital surface models display the heights of all buildings within the map. Additional tools within the layer allow us to explore data more deeply through a perspective of the elevation and depth of each area of the map.

We can also use drones to measure distances and square footage areas of a roof. Our team can quickly outline different areas of an orthmosaic map, like certain sections of a roof, and take survey-grade measurements. Our tool set includes measuring distance, area, and volume. Not only can we get measurements for horizontal planes, we can use the flight data from the drone to understand the elevation of each surface. This allows us to get accurate measurements for sloped surfaces, including ridges, hips, valleys, rakes, and eaves. Traditionally, measurements were taken by hand, which took days for a high school of this size. Using a drone image to analyze and measure a roof takes minutes without putting our employees in potentially dangerous situations.

Photogrammetry 3D Modeling

Drones also provide us with 3D models of our projects using a process called photogrammerty. Using a similar process and photos from an 2D orthmosaic image, we can create a 3D model that can be zoomed in and rotated for 360 degree evaluation and measurement. This is similar to Google Maps Street View, where you can observe a 3D perspective of a traditional 2D map. 

Photogrammetry gathers measurements and data of an object by analyzing the change in position from multiple drone images. It uses the photo's perspective, advanced processing software, and photo analysis to create a 3D model. By combining enough overlapping images of the same features, photogrammetry software can be used to generate photorealistic 3D representations of buildings.  

Photos from our drone are uploaded into a 3D mapping engine that will define high contrast points in the photos and paste them together based on those points in 3 dimensions. It then renders a 3D model, overlays the graphics, and produces a Google Earth-style map. The 3D model is a accurate re-creation of the building. The image can be rotated 360 degrees and zoomed in for more detail. For the example 3D model below, our drone captured over 150 images in about 20 minutes. There are some “digital imperfections” in the model, which distort some areas of the image. For a more accurate model, more images would need to be taken from different angles to increase the fidelity. Overall, 3D models give us the ability to view a project in a new and engaging way. The next step will be to take this information and use it in Revit to aid the the design process of buildings.

Cinematic Photography and Video

Before drones existed, aerial images were taken from a helicopter or airplane. Although the “old-fashioned” way produced good images, the process was inconvenient and very expensive. Drones can easily capture aerial images and video of building projects at lower, more reasonable altitudes. Our drone is becoming an essential part of our in-house photography toolkit as it provides higher resolution images than our DSLR camera with a “virtual” tripod that extends 400 ft into the air.

Drones allow design teams and building users to experience their projects from a different perspective. We are using drone video for marketing purposes, which enhances the experience of the design by offering a full, 360-degree visual. Cinematic flyovers of our projects provide an expansive view of our building projects within the context of the surrounding environment. Flyaround videos provide us with an intimate examination of details at levels out of reach at a human scale.