What iOS are you using? and what model iPhone? I see ARKit should work with any device running iOS 11 beta (and presumably above) but I can’t speak from experience if this is true or not.
Using i0S 11 on an iphone 6s which is supposed to be supported, and does run other iOS Arkit apps like Ikea Place.
@ I’ve had this recently! Are your material settings in Project Settings - IOS set to a “Metal” that your iPhone6 can support?
Also your Anti aliasing settings in Project Settings - Engine - Mobile, try lowering your Mobile MSAA, on my iPad Pro I can’t go higher than 4x MSAA without the app doing exactly what you’re having.
Is there even any way to get proper shadows? I know that Unreal has problems with casting shadows on translucent materials, but there’s a NEED for soft shadows that are real-time in AR.
Has anyone had any sort of progress on this? I would love some pointers on how to achieve this.
Apple supposedly has a hundred folks working on pushing forward AR - how many people does Epic have on it?
@Elliot_MM I’ve seen some videos of ARCore having dynamic lighting and shadows from what it reads from the camera, other than that I don’t know about ARKit and it’s shadows.
Yeah, still looking for a solution for shadows 
You should be able to apply an unlit material using a similar setup as the ARKitCameraMaterial (“AppleARKit Content” section when you switch on engine content) uses to any geometry you wont to have as a shadow catcher or occluder. Thats the way I’ve done it on previous AR projects using Vuforia and way back pointcloud.
I wish Oculus hadn’t bought pointcloud and shelved it, that tech was never perfect but it had stable SLAM on much lower specs than either ARKit or ARCore and that was years ago.