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According to https://learn.microsoft.com/en-us/windows/mixed-reality/design/spatial-mapping#occlusion, if you need occlusion for your game object, Spatial Mapping needs to be enabled in your Unity project. Please navigate to [MixedReality Toolkit Component] -> [Spatial Awareness] -> [enable Spatial Awareness System].
Based on your selected Spatial Observer, you can change the display settings. Choose “Occlusion” from “Visible” in Display Settings to hide MRTK built-in Wireframes.
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