Is there a solution to the existing ground showing up on top of the design surface in a cut area?

Question

I have a road that has a fairly large cut section but when I take it to Lumen to render and animate it the existing ground shows up on top of the proposed surface. 
 
 So the only design surface I can see is areas that the grade is higher.

Mark Marnell · Answer

Create a clipped terrain that removes the existing ground from under the proposed road before sending the model to LumenRT.

Mark Marnell · Answer

One example - old version but workflow is still valid. 
 https://communities.bentley.com/products/road___site_design/w/road_and_site_design__wiki/17434/video-terrain-model-clipping 
 Basically, any shape can be used to clip a terrain, either Internally or Externally. You could also create a terrain of the proposed road, and use that to clip the existing terrain.