3D Scanning at Belvedere Palace

06 Mar 2023

So far I’ve used PhotoCatch (which is a wrapper for Apple’s RealityKit API) for my 3D scanning. I thought it would be fun to try some other softwares to see what they can achieve. Looking for other contenders in the photogrammetry landscape I found AliceVision’s Meshroom, RealityCapture and Agitsoft’s MetaShape. My primary machine is a Mac, but I was also open to use my old gaming PC. Sadly most photogrammetry software packages use CUDA which immediately disqualifies my rig with its old-ish MSI Radeon RX 570. In the end I went with MetaShape and I found it quite good. The standard edition costs $179 but the software comes with a generous 30 days evaluation period. Enough for me to run some experiments.

According to the weather forecast today should have been a warm enough but generally overcast day, which is perfect for 3D scanning outdoors. I packed my Canon EOS 500D, the EF-S 18-55mm kit lense and my Canon EF 70-200mm lense. But it was quite windy and the sun would peek through the clouds from time to time, so I was not sure what to expect from my scans. I came home with over 1700 RAW files, 160 HEIC and 9 video files. At some point my DSLR ran out of juice, which pretty much ended my trip. On the way out I snapped a few more pictures and videos with my phone.

Now for the tedious part: Splitting the photos into several folders for each model, make sure the focal lengths match, convert the HEIC photos to JPEG so MetaShape could process them, etc.

I experimented a lot with MetaShape but found myself just asking for the highest quality results. On the Macbook Pro this would yield results in a reasonable amount of time as I had only small amount of photos per model. Most of my scans came in at under a hundred photos each. Also many of the subjects were too large, high or far away and I wished I could have done the scans with a drone. The 200mm helped significantly, but many angles you just can’t get.

Since it’s still quite cold in Vienna all of the fountains and wells were drained. Here you can see a turntable animation of one of the center sculptures.

Statues in the front of the building, scanned only with an iPhone 12 Pro 4K video.

Another annoyance is Apple’s preview that sometimes does not apply textures. In other instances the texture mapping would get messed up randomly and would also no longer work in Blender.

Neither MetaShape nor PhotoCatch had much success resolving the intricate metal structures of the gates. I assume many more photos are needed to get good results there.

Here are a few more details I captured.

In the end I got so much material that I’ll be busy converting everything into 3D and cleaning the models for a while.

Sidenote: Overall I’d be happy to have software that supports the organisational part of photogrammetry. Dump in bunch of photos, it reads the timestamps and GPS, makes a best guess of which parts of the series belong together. It would also provide a batch export of photos in a preferred format (PhotoCatch won’t take my RAW files, MetaShape doesn’t like HEIC or videos). On the Mac it could just wrap RealityKit to give fast (or even final) results. Finally I could have title, description, GPS and tags to make the models easier to find. Bonus points for integrating with Sketchfab, Turbosquid, to present or sell the models. There are plenty of cloud based photogrammetry solutions, it could also integrate with them. Backup to some cloud service (S3, Blackblaze, etc.) would also be nice.