As a new addition to this updated post, I added Autodesk Recap 360 which isn’t an app but does have a web interface that works on Android making it a good alternative for the discontinued 123D Catch.
This post originally also contained the Seene app. But this has been discontinued since it was acquired by Snapchat and that review has been removed from this post completely because it didn’t offer 360° 3D capture anyway.
Dedicated 3D scanning hardware is getting more mobile as we speak. While Structure Sensor and RealSense are still more tablet devices, recent and upcoming solutions like Google Tango, Bevel and Scandy Pro are meant to be embedded or clipped onto smartphones.
anBut while depth sensors are indeed getting small enough to be pocketable soon, pure-software photogrammetry solutions that can generate 3D objects from regular 2D photos are getting smarter and faster, too. So I started asking myself:
Do consumers actually need dedicated 3D capturing hardware for their phones if just software can do the trick?
To test the current state of software-only mobile 3D scanning, I tested different smartphone photogrammetry solutions on the same object under the same circumstances:
Part of the Hacker Unit accelerator program, the developers of this app have taken another approach to capturing the photos required to generate a 3D model. Instead of taking separate pictures, the app will initiate a burst mode that automatically takes a maximum of 70 photos while your path around the object is being tracked. This greatly speeds up the capturing process.
Unlike 123D Catch, Trnio does allow loading existing photos from your iPhone’s Camera Roll. You can even send an upload link from the app to your email address. This creates a new project in the app and allows you to upload photos to that project from your computer. That feature is still Beta though and only accepts photos (80 max) in a .TAR file, which is a kind of .ZIP-file for servers that requires special compression software.
After capturing, downscaled versions of your photos are uploaded to the cloud and processed. In my case processing was a little faster than 123D Catch, but that might have been because the queue of this relatively unknown app is less crowded. When the result is downloaded, you’ll get a notification (Yes!) and can view the Preview. The app features an ingenious cropping feature that allows you to select which parts you want to keep by making a selection from the top and side view of the model. That doesn’t give you total cropping freedom, but works pretty fast. Unfortunately, the model has to be re-processed in the cloud to be cropped.
If you like the model you can also choose to upload the full resolution photos for better textures. The model has to be reprocessed for this, but the result is worth it.
The Trnio app itself is also a kind of social network. It allows others to follow you and like your work. You can make a profile similar to Instagram, but somehow my own captures don’t show up on my profile page. Like Instagram in its early days, you can’t share a link to your capture on other social networks directly. You can, however, export your capture to the online 3D showcasing website Sketchfab, which is no surprise, since Sketchfab’s CEO Alban Denoyel is one of the mentors at Hacker Unit. This procedure does require you to visit Sketchfab in your browser and copy & paste the API token to Trnio, but only the first time.
You can supposedly also send a temporary download link of the model to yourself through email, but the link I received didn’t work at the time of writing.
Trnio is currently iPhone-only, but an Android version
can be expected in 2016. No Android version as of January 2017. I guess the Trnio team is focussing on their animatable 3D avatar solution instead of the 3D scanning app at this moment.
This is a direct, uncropped, export from Trnio in High Resolution Mode. This makes the textures really sharp: just look at the texture on the book cover!
If you set the rendering of this embed to MatCap, you can see the difference in texture on the arms and the edges of the shirt. Teddy’s eyes are also somewhat visible without the textures. The model has 159.6k faces, which is actually quite good.
This Android-only app developed by SmartMobileVision doesn’t feature any social features yet, or even an account registration system. But after logging in with a temporary username, it does have features that make it different than the apps above. The most important one is that it doesn’t do cloud computing but instead does all calculations locally on your phone. While the speed of this greatly depends on your phone’s processor—and naturally drains the battery—it worked surprisingly fast on my Nexus 5X. You can do other things on your phone while waiting, but that impacts the waiting time. The upside is that you don’t have have to upload and download anything while making captures on the go.
Both the 3D Model and the Photos you took are stored locally under “My Models”. You can also import image sets here, but they have to be numbered a certain way (name001, name002) and be a complete sequence. From here you can (re)start the processing of an image set.
One other thing that sets Scann3D apart is that it offers fine control over the capturing and processing quality. There are Low, Medium, High and very High Presets, but you can also enter Advanced Mode to enter custom settings. The Image Size is capped at 1920 x 1080 pixels, anything larger is probably unrealistic for phone-based local processing.
You can export the 3D model as .STL, .PLY or .OBJ file directly from the app. It saves it to a dedicated SCANN3D folder on the local storage of your phone. This way you can either send it to yourself through email or upload it to your favorite cloud storage, like Dropbox. Just remember that on newer versions of Android, you have to turn on “view local storage” from the 3-dot menu in the left corner of the file browser. Then the Local Store will appear in the drawer on the left, letting you browse to the correct folder. It would be nice to see native Android sharing (to Dropbox, Google Drive, etc) from the app.
Scann3D can also share directly to Sketchfab and is one of the few apps I know that doesn’t require users to manually copy & paste the API token, but instead login to Sketchfab directly from the app itself to authenticate.
It’s good to know that the app—which is currently in Beta—is being developed very actively. Even within my reviewing period, I got an update with a new viewer to try out! The geometry will probably improve with each update as well.
I did a capture in High Mode and Very High Mode (pictured). The later took almost twice as long to compute on my Nexus 5X—about 45 minutes. In this mode it did pick up a bit of stray geometry from the tripod in the background. It’s neglectable compared to 123D Catch, but it does shift the center point, making rotating around it in the Sketchfab embed harder.
The High version has 73.7k faces and the Very High 84.7k. That makes the polycount about 10 times lower than 123D Catch and half of the that from Trnio, which is visible in the details of the mesh. As you can see in MatCap rendering mode there are no actual details in the geometry. As you might expect, the Very High version’s textures are a lot sharper.
In the original post I never considered Autodesk ReCap 360 — the web-based interface, not the desktop program called ReCap 360 Pro — a contender for this list because Autodesk had the 123D Catch on all mobile platforms which used the same cloud-based photogrammetry engine. But now that 123D Catch is no longer available, ReCap 360 is the only way of accessing an industrial-grade photo scanning engine from an Android smartphone (unfortunately, it doesn’t work on iOS)— for free.
To keep this post tidy, I made a separate step by step tutorial for this solution, including a workaround to also share the result on Sketchfab directly from your Android phone since ReCap 360 can’t do that natively:
In short, you will make the photos with a regular Android photo app and upload them to Autodesk ReCap 360 through its web interface. The free version only allows the “Preview” quality, but this is already great for most purposes and better than the two apps above. ReCap 360 also offers an automatic smart cropping feature, which worked perfect for all my object scans.
Since I added this example later I captured the same Teddy bear on a different location. I’ll add it for comparison now and make a new capture at the same location as the other later.
With 228k polygons it’s clearly the best of the three and the when comparing the geometric detail in MatCap mode this proves that Autodesk’s engine is very good. Smart Cropping did a good job, with no orphan geometry flyng around. The fact that the still offer it for free (there’s also a free version of the ReMake desktop software that uses the same engine) is awesome.
Verdict & Future Solutions (updated January 2017)
There’s no real winner here. If you’re looking for the best possible result, 123D Catch
is was the best app and it’s was available on every mobile platform. It simply allows allowed you to tap into Autodesk’s industrial grade photogrammetry algorithms—for free! It really falls fell short when it comes to automatic smart cropping and sharing requires manually downloading the model from a desktop computer.
However, If you have an Android phone, you can use Autodesk ReCap 360‘s web interface to acces the same quality results and get great working smart cropping — still for free! Manually downloading the 3D model from Autodesk’s cloud storage and uploading it to Sketchfab is doable, but not as ideal as a direct export feature.
Both cropping and sharing can all be done from the Trnio app directly, but the former requires re-processing and up/downloading of the model. This time is partially countered by the intuitive and super-fast automatic photo capturing. It has social features, but they’re in-app only, so you can’t share links on other networks. It does export to Sketchfab directly which is great for sharing. It’s unfortunate that the development of this app (and an Android version) is going slow because the team is working on 3D avatar solutions, because it has great potential and if currently the most complete native photogrammetry app. An update to the iOS app was released this week but contained only bug fixes.
Scann3D has the best interface design in my opinion and differs from the other by being totally offline—both for storage and computing. This has the advantage of not having to upload photosets to the cloud when you’re on a mobile data connection, but the downside of local computing is that it drains your smartphone’s battery quickly. It also shows the limits of the amount of geometric detail that local processing can achieve at this moment, but this could change when the algorithms improve over time.
To round it all up it’s clear to me that software-only 3D capturing has one very big problem: speed! Many people have asked my lately why they should invest in a 3D scanner if they can capture the same objects through photogrammetry for free and the answer is also: speed (plus interactively seeing what you’re doing). That might not be important for creating 3D assets in an environment where time is no issue, like a hobby or even some professional cases. But all apps above are aimed at making 3D scanning accessible for people who live in a world that’s increasingly realtime. We expect that the camera’s on our phones can be turned on instantly with a double button click so we can shoot fast, share fast and move on.
Now that 2017 has started, you can already buy two phones with built in depth sensing hardware in the form of Google Tango. There are now Tango apps that can make 3D scans very quickly, but the scan quality isn’t nearly as good as the photogrammetry solutions above. This year (Q1 as I’m told) we’ll also see the $89 Bevel 3D Scanner — a clip-on smartphone accessory — come to market. It uses laser scanning in combination with the smartphone camera for textures. I’m hoping to test it soon.
More interestingly, 2017 will also be the year when Microsoft will release their awesome-looking, almost-realtime mobile photogrammetry 3D Capture solution. I’m not sure if they will release the iOS and Android app at the same time as the Windows feature that’s part of the Creators Update due in April, though.
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