Compare Surfaces

[Loc]

Hello,
Right now I have two surfaces a existing and proposed. I can compare them just fine, the kicker is when I need to compare two surfaces under another surface. Basically I need a vertical boundary that is a surface. Is this possible?

[Opie]

Have you thought about using a tin or grid volume surface? It will allow you to see where your cut / fill areas are between two surfaces. It would also allow you to extract volumes from those two surfaces.