Unity VR Crashing


Thanks! I’ll get to testing it out later in the day and report back.


Preliminary tests confirm the scene size crashing issue has been fixed!


It seems at some times the positional tracking doesn’t “take”. I’m not sure if this is related to scene size, could how well lit the area is have anything to do with it? The application won’t crash, it will just utilize the gyro/rotational tracking. It doesn’t happen every time and I’m having difficulty pinpointing exactly what the issue is.

Another thing I’ve noticed is that there appears to be performance degradation over time. Not sure if this is limitations of the device or a memory leak, the device (iPhone 6S) does get really hot, which I guess is to be expected. The application runs very smoothly initially but the frame rate seems to gradually decrease over time.

Let me know if there’s anything else I can provide to help. I’m having difficulty attaching the app to Unitys profiler wirelessly at the moment but I’ll keep working on it.



@tomb Are you using Unity 5.4?


@nt_ This is in 5.4.4f1. Should I roll back to basic 5.4?


@tomb - Regarding tracking not always “taking”, one aspect here is that it is best to activate tracking from a viewpoint that is close to the viewpoints you captured the scene from. If you are doing this, we expect tracking to relocalize very quickly in most cases, but it is also true that as lighting varies a lot from the scanned model, it can be less reliable and a re-scan is important to improve it.

Over time, we will make things better so it is more stable even under more changes and bigger differences from the captured viewpoints.

However, in order to find out if the issues are related to the Unity plugin or to the underlying tech, could you try out the Bridget app and let us know if you experience the same difficulty?

PS - for your application, do you need tracking which is drift-free, or do you only need 6-DoF and drifting a bit is OK (i.e. objects will not stay perfectly fixed to the same place in the world)?


Thanks Jeff. A little drifting would be acceptable, do you recommend an alternate solution?


Try the StructureUnityUBT plugin in Structure SDK, and let us know if this drift level is acceptable. This is another plugin we provide, but it doesn’t integrate with VR yet. It would be good to know if it’s acceptable to you, and maybe we can make it available in VR. (One note is that you would also loose the obstacle avoidance mesh, since the tracker would be drifting and not 100% snapped to the world)

Also please do run Bridget and tell us if the tracking “taking” issues are also happening to you there.


Jeff, Bridgit seems to work fine. I think it’s a lighting issue with my environment, I’m experimenting with the UBT tracking with the head rotation disabled (using GVR head rotation instead). The combination seems to work quite well. Thanks for your help.


Thanks @tomb – Are you experiencing lower latency with the GVR head rotation? Curious why it’s better for you than the UBT rotation, maybe we can improve it.


It seems that it doesn’t get ‘off-axis’ quite as much when performing certain movements. Still testing this though, sidetracked with other projects.


@neil1 Have you changed the SceneKit node? Within Assets.scnassets you can access it. The node itself is the word below the header “Scene graph” within the SceneKit entity graph. You can open this sidebar by clicking the little sidebar icon highlighted in blue on the lower left of the .DAE display area (blue icon at the bottom of the screenshot).

Keep in mind that all the other instances of theExistingItem.dae need to be changed to yourReplacement.dae, but this can be done via the Find and Replace function in the main project navigator on the left (not visible in this screenshot).

Post a crash report if this doesn’t work!

#include good luck