Derelict Cottage

Drone Structure Scan - Derelict Cottage

Drone Structure Scan of an old derelict cottage in Midvale, Perth using a tiny DJI Spark drone and processing with Metashape.

Mission Summary

• Goal: To create a better result (compared to previous scans) for framed structures from drone scanning and photogrammetry
• Tech: DJI Spark, Agisoft Metashape
• Conditions: Afternoon, stormy and windy
• Outcome: Using a combination of proximity manual flying and multiple sweeps, this is one of the best reconstructions of a framed structure that I have completed, albiet that I could only process using a medium quality setting.

A detailed 3D model of a derelict cottage created from drone images. The roof framing, broken panels and missing sheeting all contribute to a complex and difficult model to create. Having a good awareness of the software's needs plus clever flying techniques are critical for success.  

Obtaining a good drone scan of a structure with multiple framing members has always been a challenge for me. The software requires photos from every angle, however usually a drone scan only encompasses and external orbit or two plus a naidar plan.

Driving along the highway I noticed this cottage that looked like it would make a great case study and would assist in developing my skills. It was a great site, far enough back from the road not to be a danger to vehicles passing and no high obstructions to hinder the drone either.

In order to capture images from as many different angles as possible required manually flying this mission. Usually I start by conducting a naidar flight path to give a good boundary to the project, then one, two or maybe three orbits. This time in addition to those, I also thought about how I could capture more details on the roof framing and took the DJI Spark into some proximity flying to highlight those areas.

Unfortunately, for the model, I have to run the Metashape processing on medium quality as my laptop can't handle anything higher. Even on medium it still took 3 days to progress through the processing steps of image alignment, building the dense cloud, creating the mesh and applying the texture. In the future I hope to give more justice to the model by being able to increase the processing quality settings.  

For a mission like this, manual proximity flying and creative flight angles are key to success 

It can be seen from these images below of the model that the roof timbers have been reconstructed quite accurately (taking into account that the processes settings where set to medium quality). Whilst I did not capture images from below the roof timbers, top and all sides have been covered.

From this closer view, the complexity of the model can easily been seen

Roof timbers, whilst not perfect, have been recreated with a good level of representation

Having even light across the entire project is difficult, especially in sunny Perth. High contracting, dark shadows can really affect the outcome of a scan. On this day it was stormy and cloudy, which means that we have lovely diffused light, no hard shadows on the south side of the model. The trick was dodging the storms and rain showers, but again in Perth, that's not an all day affair.

A cloudy day assists in creating an even texture to the model, especially on the south side of the structure 

Enjoy the orbit of the finished 3D model or click in the screen below to explore it in more depth.

Derelict Cottage by The Aero Scout on Sketchfab

This has been another 'drone adventure' in aerial surveying, inspection and mapping by The Aero Scout.

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