Epic Games introduces reality capture using an Android device.
Epic Games and Capturing Reality announced today that their photogrammetry app, RealityScan, is now available for Android devices, after being available for Apple iPhones and iPads for over a year.
Once used primarily to create objects and detail for game environments, apps that use smartphones or tablets to create 3D images and models for the purposes of viewing them, inserting them into an industrial or architectural scene, and other uses are being seen in increasing numbers.
RealityScan used photogrammetry to create its 3D images and works much in the same way as photogrammetry apps: you take a series of still photos orbiting the object from slightly above it, at an angle about 30 degrees from the horizontal. RealityScan has the same advantages (ease of use, cheap or free) and disadvantages (you can’t photograph shiny, clear objects and you need even ambient light, as with other photogrammetry). Shadows and reflections throw it off.
Why RealityScan is not using the iPhone’s built-in LiDAR instead of photogrammetry is bit of a puzzle.
The app is free and meant to let one and all (now that it includes Android users) make 3D images using their smartphones. You have to start an Epic Games account to download the app. Users will then have to create a Sketchfab account to receive the model and be able to post it where the world will see it. Stetchfab may be the world’s favorite 3D model marketplace. You can also import the model to Twinmotion, which is powered by Unreal Engine and is used for real-time visualizations for architecture, consumer products, transportation, fashion, etc.
Sketchfab users are usually limited to upload 10 sets of photos as long as the total size is less than 100MB per set —
or about 50 photos on an iPhone 12— but RealityScan users are automatically upgraded to Sketchfab Pro for free for one year on their first upload. This means that they are able to perform 50 uploads (or unlimited if they are downloadable) of up to 200MB. This file size limit is related to the 3D file and not the size of the pictures themselves. Lastly, the default setting for Sketchfab uploads are private, and users must opt-into sharing their models publicly. Sketchfab’s lowest priced plan is $15 a month. You can’t pay for it on a monthly basis, though, so the real price is $180 per year. The default setting is “public,” meaning your pathetic first scan will be available for the whole world to see.
Truth be told, my first scan of an office chair was less than successful. Here’s how it went.
It only took being told not to scan a shiny or clear object to turn everything around me into a shiny or clear object. But I was finally able to locate something drab enough to work: a desk chair with a fabric cushion and back.
It took about a minute to take about 20 photos all around and slightly above the chair. Because the camera sees beyond the chair, it also adds points where it sees walls, other furniture, desks, wastebaskets, clutter, and so on. Most of this gets easily cropped out on the phone screen using intuitive pan and zoom (two-finger and one-finger touch) and pushing or pulling on handles until you have pull cropping planes that can be used to form a snug box around the chair. There does not appear to be a way to remove the floor without taking a chunk out of the chair’s wheels, however.
Press a button to start the upload and the photos are sent to the cloud where they are processed to make the 3D model.
But expecting the quality of a scone (shown above) with a mere 20+ photos may have been unrealistic. After a few minutes of number crunching on the cloud, a model of a chair appeared that was missing an arm and part of the back—it looked as if the chair had been blown up. I can understand how the seat post was missing: the angle of view, the seat obscured the view of the post. It was harder to explain how the application added several flat areas to the chair’s back and one of the armrests.
Clearly, Unreal has some work to do. Despite the “over 200,000” downloads claimed in the announcement, only 62 people bothered to leave reviews and of those who did, most gave it only 1 star, leaving the app with a mere 2.3 average rating (out of 5). By comparison, Matterport and Polycam (rated by 26,000 users), which both implement LiDAR, each got 4.7 stars.
