8d22407ca0
Explicitly set the Midlevel and Scale values for Displacement material nodes during Import. This is necessary for "constant" displacement, where the incoming UsdPreviewSurface does not have midlevel or scale data associated with any part of the node graph. We default to Midlevel and Scale values of 0.5 and 1.0 respectively; as that's what the prior code assumed, and will closely match what is seen in `usdview`. Pull Request: https://projects.blender.org/blender/blender/pulls/139510