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Wikitude Camera has a FOV of "NaN" when Image Tracker is enabled


We are using Unity 2020.3.2 to build for UWP.

We are using the Wikitude SDK 9.6 Professional Edition.

We are facing yet another device-specific error :

One of our clients was using the "Latitude 7220 Rugged Extreme Tablet" (Windows 10 tablet) and everything was working fine.

Then they upgraded to the newest "Latitude 7230 Rugged Extreme Tablet".

Since then, AR is not working anymore. Wikitude is not able to detect any ImageTracker or InstantTracker. Actually, sometimes it works, but most of the times it doesn't...

No error is displayed by the Wikitude SDK.
However, I have found that after activating the ImageTracker gameobject, the WikitudeCamera's Camera component has a FieldOfView of "NaN" and also "NaN" values in its ProjectionMatrix.

I have printed a bunch of properties of the camera and it is the only thing that stands out. Please see the attached screenshot.

I have also attached some specs of each tablet model, not sure if it can help.

It is the first time we encounter this issue and we can't reproduce it on devices (UWP or Android), but I hope you may have an idea of why this is happening and if maybe this is something you have fixed in the latest versions of the SDK.

If you have any information about this issue that is preventing our client to use AR at all, please let us know.

Kinds regards,

Thales team


it seems like I somehow skipped over the last part of your comment and assumed that in your previous comment you referred to the 9.13 Expert Edition, not the Professional Edition. I'm really sorry to give you false information. This was not intentional and I hope I didnt' cause too much confusion and anger.

Regarding the UWP crash I already gave you an answer in your other post, but in short: Unfortunately there's an issue with UWP in the current Expert Edition and we're waiting until we can release 9.14 which includes a fix in order to get rid of this.

Right, this sounds like a very specific edge case indeed. I'm glad to hear that you found a work-around for now, although this is far from satisfactorily. Since we can't reproduce mentioned issue with our devices available we're still hoping that using the Expert Edition SDK 9.14 (with the UWP issue fixed) will get rid of the issue. We're letting you know once it's available and please give us an update once you have the time to try out. If it's still not working we will take a closer look into it.

With best regards,



"we really hoped that switching to the current Expert Edition could get rid of it."

>>> In my post I said I was not even able to test the 9.13 Expert Edition samples because it looks broken on ANY device. It is not related to my initial issue. The Unity UWP Expert Edition just crashes (app closes) when starting AR on ANY device (PC, Windows tablets with different models). I feel like I am repeating myself from this post ( ), but are you sure the UWP Expert Edition is actually working ?

"However it seems not to be on the SDK side (since that issue doesn't happen on other deices) but the specific device itself."

>>> I mean, I wouldn't say it is entirely the device that is at fault here, but an incompatibility between the SDK and this device, or an edge-case not managed by the SDK.

Vuforia Unity samples are working fine with this device...

Our current and only work-around is to destroy/re-create the Wikitude camera and trackers in a loop until the SDK initialize correctly which is can take up to 4-5 tries (~15 seconds).

Best regards

Hello Thales Team!

Since the issue you've described was initially happening only on the Professional Edition we really hoped that switching to the current Expert Edition could get rid of it. As that's not the case we'll treat the issue more serious. However it seems not to be on the SDK side (since that issue doesn't happen on other deices) but the specific device itself. Because of that we won't give it a too high priority since there are more fixes and QoL improvements ahead, affecting all sorts of devices and users. So to be honest I don't think that we'll start working on this issue soon and I'm sorry about that.

With best regards,



To add some more about this issue :

The client sent us one of their device (Latitude 7230 Rugged Extreme Tablet) and I was able to reproduce the issue.

However it only happens "sometimes", I would say 2 times out of 3, creating a WikitudeCamera then an ImageTracker will make the Wikitude SDK go wild and the Camera projectionMatrix and fieldOfView show NaN values.

But sometimes it works just fine.

I was not able to find a constant reproduction scenario (e.g. starting the camera, waiting 5 seconds, then creating the ImageTracker... or having to restart / reinstall the application...) : it looks like the issue happens completely at random.

Note: the Latitude 7230 Rugged Extreme Tablet where we reproduce this issue is in fact in Windows 11.

Also, as I have mentioned here :, I was not able to test with the Expert Edition 9.13, since the UWP application crashes on all my devices (PC and all my tablets) even when I try the Sample App from Wikitude.



We have have tried using the 9.13 SDK as you suggested (with a trial license), unfortunately this did not resolve the issue, the behavior and FieldOfView values did not change, AR is not usable at all.

Please, let us know if you are able to track down this issue.


Thales team

Hello Team Thales,

this sounds like a very specific issue indeed. We will have a look into it and see if we can reproduce the issue and find anything.

In the meantime have you tried upgrading your SDK version to the current 9.13 version? The SDK you're using is over two years old and maybe the issue might be resolved just by upgrading (just a guess, though).

With best regards,


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