Just a little update. So the image I showed was taken with a progressive immersion style. Probably because of how the soft edge fade in progressive works. the passthrough is not available with OcclusionMaterial() but if you switch to a mixed immersion style the OcclusionMaterial() works as expected! So in this mode it should be possible to build a box with an opening and having stuff come out of the "portal".

Thanks! Yes I found an old session from 2019 where they talk exactly about this for iOS: https://developer.apple.com/videos/play/wwdc2019/605/?time=1012 The OcclusionMaterial() can also be created on VisionPro the but the material will stay black, and the pass through video is not revealed Furthermore: when experimenting with their "Portal" Solution we are facing more and more issues. For example it's super hard to work with any kind of window or view inside the portal. And there is no glass effect, the UI looks flat. Also there are some rendering issues when other UI layers appear, like the control center for example... Generally the Portal seams a bit half-baked, but without an Occlusion Shader it's very hard to make these kind of experiences. When trying this app you will notice that they will switch your something around when your head gets close to the door. But it seams like they have an working Occlusion Material: https://moonvrhome.com/spatial-portal

I think a occlusion material could work. So instead of having a positive shape with the portal material you would put the user in a box with an occlusion material applied to the inside and with an opening in the front. The ground assets close to the portal can be cliped in the 3D content creation software so that they dont pertrude the mask. If you want you could combine it with a flip/flop to change the shader behaviour when you are looking at the backface of the mask... Whats also really good with "Encounter Dinosaurs", is how the lighting on the 3D meshes changes as they come out of the portal. It blends between the IBL of the scene and the IBL of your current environment. You can see a similar effect happening when playing around in a progressive space with the digital crown, but the effect in the experience is much more localized and precise. Any idea on how to create such an Occlusion Material in RealityKit? I guess one would need to write it in Metal. I took a look a the custom nodes in RealityComposerPro but could not find anything.

Yes you can. I managed to do it using a regular attachments. But be aware that the attachment API has changed from the original documentation: https://forums.developer.apple.com/forums/thread/736588 So in my RealityView that is my immersive space i add after content.add: // Portal is created 2m from you with root of immersive space being where the user stands. if let portalCenterAttachment = attachments.entity(for: "portal_center"){ portalCenterAttachment.position = [0, 1.25, -2] immersiveContentEntity.addChild(portalCenterAttachment) And then after closing your RealityView you need to create the attachment using this new syntax: attachments: { Attachment(id: "portal_center") { MyPortalView() } MyPortalView() is your RealityView with the makeWorld() and makePortal() in it. I think that all still works as descibed in: https://developer.apple.com/videos/play/wwdc2023/10081