USDZ models look broken on iOS 18 / visionOS 2 beta

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Created 1d

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I noticed that with the 4th betas of iOS 18 and visionOS 2, some USDZ models' texture mapping looks completely broken. The issue occurs only with a device, not with the Simulator. It's a regression, the models look fine with iOS 17.5.1 and visionOS 1.2.

The issue occurs if I load a model as an Entity in a RealityView iOS or visionOS, or in a SwiftUI 3DModel view on visionOS.

Has anyone seen this too? Is there a workaround?

I filed a bug report with a minimal example project, it's FB14473756.

Screenshot on Vision Pro device: Vision Pro Device - models broken.jpg

Screenshot on Vision Pro Simulator: Vision Pro Sim - models ok.jpg

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Answer 1

Vision Pro Engineer OP

Apple

21h

Hey @Vielfalt,

This is expected behavior. Our platforms now support rendering of Catmull-Clark subdivision surfaces. This is what is causing the difference in rendering.

Your USD files omits the subdivisionScheme property, which according to USD spec, means that the mesh should be treated as a Catmull-Clark subdivision surface. In order to keep the previous behavior, generate your geometry with the subdivisionScheme property set to “none"; this indicates it is a polygon mesh and not a subdivision surface.

Let me know if this helps,

Michael

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