I'm trying to render (Revit7) an inground swimming pool. I cut an opening in the topo surface and built a concrete box with a concrete floor in the ground.
Then installed a water surface 6" below the lip of the walls. The water surface is a floor 1" thick with the color "water" as the material. I tried a membrane as the water but Revit didn't like a thickness. I would like it to be transparent. Should I use glass as the floor? In shading with edges, everything looks fine, but when I render the scene there is no opening in the ground and the water surface does not show up.

The goal is to see the pool water surface and the inside corners of the pool walls and steps from different views.
Any help would be appreciated.

Bill