We’ve maintained a guide to 3D scanner apps for iOS and Android for quite some time now, and the most frequent comments we get on it are “it’s all iOS” or “where are the Android apps” and further variations of this specific message.
For the longest time, Android users have been plumb out of luck for any form of native or well-presented 3D scanning on their device. Of the limited options that do exist, they’re mostly terrible, providing poor results and worse usability.
Catching our eye recently is one promising new option that could, finally, offer a half-decent scanning experience on Android. It’s by the folks of the ill-fated Phiz smartphone-based turntable 3D scanner, and it’s called Kiri Engine.
The app has been available on the Play Store since December 2021. It gets regular updates, with user feedback through a lively Discord server influencing what comes next – features such as a desktop interface for Premium users to upload photographs not captured inside the app is one such example.
The core concept hasn’t changed much since its release: connecting the convenience of the camera you carry (your smartphone) with photogrammetry processing power in the cloud.
This is not notably different from previous and current Android and most iOS-based scanning apps. Besides newer iPhone models, smartphones don’t carry the sensors required to natively capture scanning data. Fortunately, one effective and accessible method of 3D scanning is photogrammetry – stitching batches of photographs taken from all angles to cover an object. A point cloud can be made from common reference points across overlapping areas of the images, meshed, and combined with the color image data to give you your 3D model.
You only need a camera, and most smartphones carry competent camera tech. Ergo, through technomagical app wizardry, you can whip your smartphone out of your pocket, fire up an app such as Kiri Engine, and be snapping a 3D scan within mere moments.
Kiri Engine’s advantage is that its creators seemingly know how to put together a pleasant-to-use app, leading you from the capture stage to job queuing, processing, and the model finally landing in your library for you to download and admire.
While it’s not a patch on the instant gratification of a lidar-equipped iPhone building the 3D model as you go, Kiri Engine’s scanning process is a simple-enough jaunt through a simple camera interface. We’ll admit the control over image capture is a bit spartan – you have no control over shutter speed, focus, and others settings you might want to control.
The app will give you a hint as to the quality of your photography. Depending on the number of photographs you’ve snapped, it’ll assign you a sort of score ranging from “Acceptable” to “Good”, and finally “Perfect”. It’s unclear if you achieve these quality tiers through the quality of images or quantity. We typically only ever hit “Good” just as we bumped into the 70 photograph limit for free users of the app. Oh yes, it’s freemium. More on that in a second.
It would be nice to see an indication of any angles or insufficient overlaps, something you get when using desktop (or even some mobile) photogrammetry software. As such, 70 photographs is a reasonable number to lap a moderately sized object a few times over.
Trialing a few scans under different lighting conditions, we captured some scans that could be suitable for 3D printing. Take into account that post-processing will almost always be necessary to isolate the object in focus from its background and wrap the model to be watertight.
By default, your scan includes the texture data. It is, after all, generating a scan from full-color photographic data. Your model is photorealistic from the get-go.
Kiri Innovations does not indicate the dimensional accuracy or limitations of the scans it produces. As a 3D scanning process, photogrammetry provides models as good as the data you give it, so take care to capture your model from all angles. Capturing Reality, the folks behind the highly-rated RealityCapture desktop photogrammetry software recommend moving no more than 30 degrees between the images of a surrounding pass and getting up close to capture details.
Kiri Engine is, effectively, free to use. You can generate scans without logging in, but you won’t be able to download the resulting models. Punching in some details to establish an account grants you the ability to export using the app’s token system. Free users get three download tokens a week. Using a token on a model effectively “buys” it, unlocking repeated exports without redeeming more tokens.
If you run out of tokens or don’t wish to use one of your remaining tokens on a model, you can make a single purchase for $0.99.
A premium subscription exists, too, giving, in addition to unlimited model export unlocks, a higher image count per scan of 200 (compared to the free tier’s 70), plus the use of the browser-based photo upload function and non-app-captured images from your device.
License: The text of "Photogrammetry on Android Is Surprisingly Good" by All3DP is licensed under a Creative Commons Attribution 4.0 International License.