Dronelife sat down with Jeff Foster, Co-Founder of Sound Visions Media, and Editorial Director of Drone Coalition to talk creating 3D models with a drone and the key steps to ensuring the results come out as best as possible.
Today, Jeff flies a DJI Inspire 1 with X3 and X5 cameras, as well as a DJI Phantom 3. In this blog post, Jeff will walk through the steps he took to create a 3D model of the abandoned Navy dorms on Treasure Island, near San Francisco, using his Phantom 3 Professional drone.
Step 1: Pick a Time to Fly
According to Jeff, one of the most important steps in using your drone to make a 3D model is to pick a suitable time to fly. Besides avoiding high winds or rain, it’s also important to pick a time with good lighting.
“If it’s an overcast day, that’s best because there aren’t strong shadows”, said Jeff. “I usually pick sometime around noon where there are the shortest shadows possible, but you don’t always get a chance to choose that.”
The worst time of day? Too early or too late in the day because that’s when the shadows are longest and will have the greatest effect on the outcome of the model. When flying at the abandoned Navy dorms, Jeff flew around 10am on a partly cloudy day.
Step 2: Capture Nadir Imagery
Jeff likes to start by capturing nadir imagery, photos captured from directly above looking down, using the free DroneDeploy flight app. He simply outlines the area he wants to fly on a base layer map, and the app generates a flight plan. Following a safety check, the drone automatically takes off, flies along the automated flight path capturing images and then lands.
Step 3: Circle the Structure to Capture Oblique Imagery
If you’re making a 3D model of relatively flat terrain, an overhead flight might be sufficient to make a good model. However, if you’re modeling a structure or rock formation with steep, vertical, or concave sides, overhead images don’t capture a good view of the sides of the structure. For this reason, Jeff recommends flying two additional orbital flights around the structure capturing oblique imagery to improve the quality of your model.
Jeff captures manual obliques by tilting the camera 45 degrees and flying around the structure at a fixed radius at the same altitude as the original nadir flight. “Then I’ll come down about half the altitude and angle the camera close to 90 degrees and circle the structure again,” said Jeff.
When capturing oblique images, it’s important to avoid capturing the horizon within your images. When Jeff makes these two orbital flights, he manually triggers the camera shutter to take each picture. However, if you’re just starting out, you might experiment with flying very slowly and setting the camera through your drone’s flight app to automatically capture images every 3–5 seconds.
In some cases, where the structure is more intricate or includes overhangs (such as the eves on a house), Jeff may even do a third — possibly handheld — orbit from an even lower angle, pointing the camera up to 90 degrees.
Step 4: Process the Imagery to Generate Your 3D Model
Once he finished flying, Jeff uploaded 504 photos from all four flights to DroneDeploy and chose to process the imagery as a “structure.” After a few hours, DroneDeploy’s cloud-based processing stitched all the images together and the 3D model was complete!