It seems that the licence is hard coded into the SDK library at the moment - if you set your date past the end of march then the API stops working if you attempt to use the body tracker .
Well technically it just hangs on calls to the reader as in:
astra::Frame frame = astraReader.get_latest_frame();
There is currently no actual error message being generated in the API that is obvious - and no way to test that the licence has expired it would seem.
Westa
FWIW - I would suggest a close look at the nuitrack sdk - it is streets ahead in terms of tracking accuracy and has some native gesture capabilities - if you can get past the poor documentation and some current issues with the install process for windows.
The API is event based and built around a set of function callbacks - but is also heavily pointer based so can be made to work with a polling structure if required as well.
It is capable of tracking up to 6 bodies at once - I think someone suggested previously that the limit was two.
BUT the api is based on a per-user licence model.
Westa
Thanks for the info. Let me take a look at Nuitrack. 
Quick heads-up regarding the nuitrack SDK - I created a Cinder block (c++) which was polling the SDK for tracked skeletons. In spite of the poor documentation I got a working boxman demo going with the Astra on Windows, tracking multiple skeletons simultanously. It reported some strange joint orientations when limbs where out of view but it seemed like I could work around that (especially since at the moment I only need to track the head position of my users).
Unfortunately after testing for a longer period of time a crash occurred in a specific situation. As far as I can see, if a single user is being tracked for a longer period of time (minutes) at some point the skeleton data will freeze. As soon as that user steps out of the tracking frame the nuitrack SDK crashes and burns. I got an opencv error message, something to do with resizing an empty frame I believe, but since the SDK is closed source I figured it wasn’t worth investigating further.
Also, about 80% of the nuitrack forum posts is Russian spam. That is an accurate description of the level of support and documentation you can expect.
Edit: to be completely fair the technical API documentation isn’t too bad and can be found here
I had to abandon Orbbec for potential licensing issues and I had to abandon the Astra + nuitrack SDK because of the crash(es). All in all not a very good experience and currently forced to keep using the Kinect, which is getting harder and harder to purchase. I saw the Kinect for Windows going for $500 on Amazon recently.
I understand there is a rush to fill the gap in the market left behind by Kinect but please keep in mind you are making these products for developers. It would be so helpful for all of your customers if there is extensive and clear documentation, including example applications for each supported platform, showing off both the core SDK and the body tracking SDK.
Most importantly, like I said before the current licensing situation forces me to abandon this product and it does not give me a lot of trust in Orbbec as a serious competitor in this field. If the situation changes I might give it another try but I will be very skeptical as I feel I’ve wasted a couple days trying to find a long term solution for body tracking.
If anyone wants to give the nuitrack block a try I put it up on GitHub. I am curious to hear if any of you have different experiences.
Did you actually make contact with the nuitrack dev team via email ? We have found them quite responsive to our questions and bug reports. And they are actively releasing updates … Have u made them aware of the issue u encountered? It’s not one we have seen during our testing
Westa
Hi Westa,
I have not contacted the dev team yet. Reading back my post now I might have been a little too harsh - not trying to bash anyone, just a little frustration coming out.
It’s not always possible for me to go the e-mail support route when I’m working with tight deadlines, plus issues like this make me very uncomfortable using the Orbbec + nuitrack setup. As a dev yourself (I presume), surely you know how to deal with unexpected program state and how to handle errors. Crashing hard with only a very cryptic OpenCV log message is not the way to handle whatever is going on there. It makes me wonder if there are other places in the nuitrack SDK where things like this might occur. Even worse, since ‘trade secret’ algorithms are used I am not able to fix issues like this myself.
I also tried to get nuitrack running on the Persee (Ubuntu 14.04. 16.06 gave a lot of cryptic error popups but is advertised as beta so fair enough. Install instructions in a docx file really?). Nuitrack advertises with Persee compatibility and offers a download for Ubuntu. I forgot the specifics but there were some lib files missing and I could only get a working build with a frankenstein collection from the persee files and the main SDK download which includes a linux ARM build too. Unfortunately there seems to be a version mismatch so certain SDK calls would not compile because of missing externals.
Maybe it was naive of me to expect (or at least hope for) a well tested, production ready library. It’s maybe unfair to compare the giant called Microsoft with relatively small companies like 3divi and Orbbec. But the fact is I was disappointed so far and I hope describing my experience and sharing my code will help others in their quest to body tracking.
That being said I took the time to write this post so I will also take the time to send an email to nuitrack describing my issues. In the end I would love to have a stable solution and I understand feedback like this might help achieve that goal.
PS. I feel like it might be better to post this on the nuitrack forum but I’m afraid of the Russian spammers.
I got a reply from nuitrack:
Dear Daan,
crashing after some period of time caused by license issues. Free trial version has 3 minutes time limit. You should activate Nuitrack to PRO version to remove time limit. Purpose of Trial version is getting ability to test Nuitrack software before purchasing a license.
Sorry for inconveniences and let me know if you have any questions.
It seems I will have to spend some $$ and it should all be fine. Hopefully I will have some time to try it out soon.
Best 29 dollars u will spend for starters… But make sure u understand their licence … It’s per user seat… Not just per developer
Westa
Oh and their documents and samples are a bit of a mess
Hi Westa,
Yes, their samples and documentation are mess only. I wanted to compare NuiTrack body tracking with Orbbec Body tracking but I was not getting anywhere with it because of the samples are not straight forward like Orbbec body tracking samples. In my experience Orbbec body tracking is much easier to implement except for the shadow problem. I think I will end up using Orbbec body tracking for my application.
Best Regards
J
Hi Johan,
Actually in many ways the NUITRACK SDK is much nicer to use and has better implementation practices.
I would suggest that its is worth a little time and effort. In terms of samples everything you need to know is in their nuitrack_gl_sample c++ sample set.
One of its big pluses is that it actually gives you access to a lot of deep control functionality regarding how the segmentation and skeletal tracking works. You can access the config and override parameters at runtime … things like tracking depths, smoothing medians, config locations and even deeper control by accessing the XML setup files for each system.
And for what its worth - OEBBEC themselves even recommend it for people needing more robust tracking systems than their native implementation.
Cheers
Westa
Hi Westa,
Thank you for that info. I am bit of a under pressure to find a replacement for Kinect . There is a pending order for 20 of them. Time is critical for me so I thought I will stick with Orbbec but on your recommendation I will try again.
Best regards
J
Looks like the “free” timer on the body tracking ran out again. Any updates???
The latest build is supposed to work until sept 2018.
Westa