I discovered part of my confusion. An entity (e.g., green cylinder) that is front of the portal is still visible as long as the portal's clipping plane isn't activated. In screenshots below, initially Red cylinder is at Z = 0; Blue cylinder is at Z = -0.3 Green cylinder is at Z = 0.3 (in front of the portal plane). Despite the green cylinder being in front of the window/portal plane, it is initially still visible as long as it is positioned between the camera and the portal window. When I activate the clipping plane, the green cylinder disappears, and the red cylinder gets cut in half. To have the green cylinder appear beyond the frame of the portal, (1) the portal has to have the PortalComponent's crossingMode set to .plane(.positiveZ) and (2) the green cylinder needs to have a PortalCrossingComponent. I am still stuck on the fact that when I move the green cylinder's Z position to +0.5, it still gets clipped. Still have lots to learn... Example screenshots: Green cylinder Z at 0.3, it appears in front of the portal but rendering is still bound by the portal. Portal's clipping plane is enabled. Green cylinder is gone, and red cylinder is cut in half, verifying clipping plane is at Z = 0. Portal's PortalComponent crossingMode = .plane(.positiveZ) and PortalCrossingComponent added to green cylinder. When green cylinder is pushed out to Z = 0.5, part of it is still clipped. Is there a limit for how far things can come out of the portal?

Resolved! In case someone else runs ints this problem, or I do in the future and find this post, here is what I did: In Apple Vision Pro, I selected Settings > General > Remote Devices The pane said it was available for pairing. In Xcode, I selected the "No eligible devices" in the destination pop-up (down?) menu. In the "Devices and Simulators" windows, my Apple Vision Pro shows up. Then I could select it and pair with it (a challenge code popped up in the Vision Pro).

I was having the same problem earlier today, but it just started downloading now.

I found the issue (sort of). kmutil is launching com.apple.fsplaceholder, so I feel better that it is an Apple thing. I still don't know what is going on, but an example capture of one of the processes is shown below if anyone is interested. launchd forks, then executes xpcproxy with the arguments (xpcproxy com.apple.applefsplaceholder), and then executes kmutil with the arguments (load -b com.apple.fsplaceholder). 														 pid: 26919 									first observed: 2020-11-17 13:54:20 									 last observed: 2020-11-17 13:54:20 												 program: kmutil 										program path: /usr/bin/kmutil 											signing ID: com.apple.kmutil 												 team ID: 			 program modification date: 2020-01-01 00:00:00 						 program status date: 2020-01-01 00:00:00 														ppid: 1 									parent program: launchd 						 parent program path: /sbin/launchd 							 parent signing ID: com.apple.xpc.launchd 									parent team ID: parent program modification date: 2020-01-01 00:00:00 			parent program status date: 2020-01-01 00:00:00 FORK	/sbin/launchd EXEC	/usr/libexec/xpcproxy arguments: xpcproxy com.apple.applefsplaceholder EXEC	/usr/bin/kmutil arguments: /usr/bin/kmutil load -b com.apple.fsplaceholder exit	

No 3rd party kexts installed.

I took a cue from this old threadhttps://forums.developer.apple.com/thread/80337and built a very simplified UIViewController with an ARView and repeatedly went back and forth loading and unloading the view and displaying my somewhat complex model.Everything worked fine, so the problem in my larger program is clearly mine. I suspect my code is complex enough that I have one or more accidental retain cycles going on.I am going to close this thread.

A quick update.I have found that if in the ViewController with my ARView I override viewWillDisappear(_ animated: Bool) and remove the anchors added to the scene before the scene disappears, then the meshes do drop back down to normal when I reload the ViewControllerE.g.,self.arView.scene.removeAnchor(self.worldAnchor!)where worldAnchor is the root anchor for most of my content.HOWEVER, eventually FPS does drop even though the mesh count is low again. That is, the more times I reload the ViewController with the ARView, the slower the FPS becomes.So I still don't know how to correct for that.