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CosbyTron
Up and Coming
June 25, 2013

Unity Freetrack Positional Tracking

I was looking into using Freetrack for positional tracking and it turns out someone's already built a nice Unity package for the job! I thought I'd share it here. If you don't have an ideal setup (infrared cam and IR-LEDs for example), Freetrack can be tough to dial in. Still, it's fun to experiment with!

Here's the package (I need to remember to sign up on the Unity forums to thank the poster :-) ):

http://forum.unity3d.com/threads/174552-FreeTrackIR-Unity3d-Full-success!

You'll want to be sure to select 3 point cap and set measurements in Freetrack, and comment out the rotational tracking code in TranslateToCube.cs and copy the DLL to your plugins folder.

To test it out, I ordered some crazy cheap little LED lights:

http://www.amazon.com/gp/product/B0018LAGZY/ref=oh_details_o02_s00_i00?ie=UTF8&psc=1

It's a good thing you get 40 in a pack, as lots of them don't work well/at all, but you only need 3 (And yep, this can be accomplished with batteries, LEDs and tape for even cheaper, but these things just looked like fun :-P).

Some double sided tape, dim the room lights and Bob's your uncle (did I use that right?).


rift-freetrack.jpg
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    4 replies

    craigotron
    Up and Coming
    June 25, 2013
    Great find! Could you please share your experiences with Freetrack and it's Unity implementation once you have something to show/tell?
    drash
    Inspiring
    July 19, 2013
    Two Tron's in the same thread? :o *faints*

    Anyway, thanks for the tip on this Cosby!
    Titans of Space PLUS for Quest is now available on DrashVR.com
    CosbyTronAuthor
    Up and Coming
    July 23, 2013
    Ha! Can never have too many Trons (well, I guess that depends on your feelings about Tron Legacy :-P )

    @craigotron - Sorry I never got back to the thread with details. I had a really hard time getting it to work well. Freetrack has to detect all 3 lights at all times and I just couldn't get consistent tracking with a visible light cam and these white LEDs. I may mod the cam to be IR only and try out some IR LEDs (which should help a lot, I think that's basically how TrackIR works with the Pro Clip), but even then, there is a lot of lag.

    I still think there's potential here, but when I realized the solution wasn't going to be as simple as "tape 3 lights to your rift," I questioned how many people would benefit from implementing support into a game.
    CaptainSplat
    Up and Coming
    December 24, 2013
    For a proper cam u need a playstation 3 eye($10 used at ebgames, one with rounded lens the newer ones have flat lens and are really hard to take out the IR filter), 3 IR LED's and 2 aaa batteries you shouldnt even need a resistor connecting them in series and you will get longest battery life too. Some people report not having to modify the ps3 cam at all using IR LEDs. myself i have an ARUCO symbol(augmented reality api) on the front of my rift and it does the xyz with ps3 cam while pitch yaw and roll are done by the rift I use Opentrack for combining the two input methods. Cant get it working in my games unfortunately, arma 2 not recognizing freetrack output for some reason same deal in arma 3.
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