Error on iOS14 when loading OBJs into MDLAsset

Question

When loading OBJs into an MDLAsset using the MDLAsset(url:) initializer (to eventually get the model into SceneKit), the operation fails frequently and inconsistently on iOS14. This operation works fine for these same files on previous iOS versions. I've also observed the bug on iPadOS, although maybe less frequently. Not sure if it's relevant, but these OBJs are pulled from server and stored locally. But this bug is occurring after files are already downloaded. Sometimes the same file will fail multiple times before randomly working, and vice versa.

The console output seems to indicate a failure to communicate with ModelIO XPC service. I tried restarting my device, but the bug continues to occur. Console output:

connection to com.apple.ModelIO.AssetLoader was interrupted
AssetLoader.loadURL errorHandler: Error Domain=NSCocoaErrorDomain Code=4097 "connection to service on pid 0 named com.apple.ModelIO.AssetLoader" UserInfo={NSDebugDescription=connection to service on pid 0 named com.apple.ModelIO.AssetLoader}
Couldn’t communicate with a helper application.
connection to com.apple.ModelIO.AssetLoader was interrupted

Has anyone else run into this issue on iOS14? Alternatively, are there any workarounds anyone has tried in the meantime? As far as I know, loading an OBJ (that is downloaded from server) into SceneKit can only be done through ModelIO, without writing an OBJ parser myself.

Answer 1

This seems to be fixed in 14.3.