I think it would be super handy if we were able to select a material in our model and turn it into a terrain element. That would allow us to easily blend surrounding terrain with whats in our models, and we would be able to paint with different materials. My firm works in revit and usually part of the site is modeled as one material for landscaping. Allowing conversion of a surface to a terrain would allow me to easily paint plant beds, and zone different areas off for different levels of grasses for views near and far from the camera