ARKit 1.5 backward compatibility with devices that don't have 11.3

I'm successfully building and using ARKit 1.5 apps with the ARKit unity plugin spring 2018 update branch on a device that I've updated to the iOS 11.3 beta. On a device with 11.2, though, the ARKit scene crashes on load.

How can I make the app backward compatible so iOS 11.2 devices can still use ARKit with the horizontal planes and 11.3 devices can use the vertical planes?

 

do you have a callstack when it crashes?

 

Don't have a callstack but I was able to find a workaround for what I needed.

Since I am only interested in vertical planes (and not Image Targets or other ARKit 1.5 features), I was able to fix the issue by modifying the ARSessionNative.mm file. I commented out all the ImageTarget related methods and put in a runtime conditional to check for iOS 11.3. Seems to work fine on my initial tests, I was able to use vertical planes on an 11.3 device but the app still ran fine on an 11.2 device using only horizontal planes.

 

https://bitbucket.org/Unity-Technol...mits/474699c8ff8c37c4824e7bc8b503e031f3d30457 might interest you - its has a runtime check for whether the device you're running on supports arkit 1.5

 

I'm using the 2D image detection, and it's working great:

but I'm having similar issues trying to maintain compatibility with pre iOS 11.3 devices. In Xcode if I change the deployment target to < 11.3 (e.g. 11.0) I get an Asset Catalog Compiler Error:

..../Xcode/Unity-iPhone/Images.xcassets: Exception while running actool: *** -[__NSDictionaryM setObject:forKey:]: object cannot be nil (key: catalog)

Looks like this has been logged as a bug with Apple, but I thought I'd mention it here in case anyone else runs into the same issue:

https://forums.developer.apple.com/thread/96235

 

Haven't had a chance to try it yet - but have you checked release version of XCode 9.3 if it has same problem?

 

Hi Jimmy - I just tried it then and get the same error

 

I also get the error running the sample image detection code, so I don't think it is a Unity issue: https://developer.apple.com/documentation/arkit/recognizing_images_in_an_ar_experience

 

Yes, we found the same issue - Apple are taking a look at it.