Transparent background & behind other views

[mbalajee]

I need a transparent background (background color of SurfaceView should be visible). I tried two approaches,

1. Setting UiHelper.isOpaque = false

modelViewer = ModelViewer(
    surfaceView = surfaceView, 
    uiHelper = UiHelper().apply { isOpaque = false },
)
modelViewer.renderer.clearOptions = modelViewer.renderer.clearOptions.apply {
    clear = true
}
modelViewer.view.blendMode = View.BlendMode.TRANSLUCENT

With this option I see the background color but the model hides other views because the UiHelper sets surfaceView.setZOrderOnTop(true)

covering.webm

2. SkyBox

I set the SkyBox color to the color of the background view (not actually transparent but I got what I needed)
modelViewer.scene.skybox = Skybox.Builder().color(1f, 1f, 1f, 1f).build(modelViewer.engine)

This does not hide other views but I see a black screen for a second (which I don't see with isOpaque = false option),

visible.webm

How do I avoid the black screen and still get transparent background?