RealityKit - PhysicalBasedMaterial - sheen control?

Hey

I'm trying to understand the pbm materials, for the moment I have this test >

     var myMaterial = PhysicallyBasedMaterial()
    myMaterial.baseColor.tint = UIColor(white: 1.25, alpha: 1.0)
    //myMaterial.blending = .transparent(opacity: .init(floatLiteral: 0.01)) /* glass material work! */
    myMaterial.clearcoat.scale = .init(floatLiteral: 0.8)
    myMaterial.clearcoatRoughness.scale = .init(floatLiteral: 0.0)
    myMaterial.faceCulling = .none
    myMaterial.metallic = .init(floatLiteral: 0.9)
    myMaterial.roughness = .init(floatLiteral: 0.5)
    let sheenColor = UIColor(red: 0.5, green: 0.5, blue: 0.5, alpha: 1.0)
    myMaterial.sheen = .init(tint: sheenColor)
    myMaterial.specular = .init(floatLiteral: 10.0)

As soon as I assign sheen, the entire material changes and I have only "sheen" control. I cant control sheen opacity, or how rough/etc it is. Its like another material on top of PBM... what do I do with it ?

TIA

RealityKit - PhysicalBasedMaterial - sheen control?
 
 
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