Cut/Fill - 3D area of EG

[wilsonm2000]

Hi

We have a road corridor surface, and trying to find out the volume of topsoil to be stripped.  We are trying to find out the 3D area of the existing ground surface and multiplying it by the average depth of topsoil.  How do I get the 3D area of both the cut and then the fill areas?  If I do a volume surface, then do a 2d level banding style, and then do a table, it is giving us the 3D area of the finished ground surface.  I tried swapping the reference surfaces around when creating the volume surface, but we just get the same result but in reverse.

Any other ideas on how to work this out?

Thanks

Martin

[sboon]

The only way that I can see to do this would be to make a copy of your EG surface and then use an outside boundary to limit it to the area of your corridor.  Once that is done the Statistics tab of the Surface Properties dialog will provide both 2D and 3D areas.

I have to ask though - why do you think that it is necessary to have a 3D surface area?  If your pay quantity is based on a depth of topsoil - measured vertically, then the 2D area is what you need.  The only way that a 3D surface area is relevant would be if your pay quantity is based on a thickness - measured perpendicular to the surface at every point.

Check the difference between your 2D and 3D areas for the full EG surface.  If they're within say 5% of each other then I would ignore the issue and just use the 2D area.

[neilyj666]

I can't see the 2D vs 3D area making a significant volumetric difference especially if you are just taking an average soil thickness...

Could extract the corridor boundary and use this as an outer non destructive boundary on a copy of your EG surface which should give you the 3d area of the EG affected and hence volume.

Extract the 0 contour (or if on 2012 MinDistBetweenSurfaces) to find the cutfill boundary and then use this along with the surface boundary from above to create cut fill areas. I'd generally copy all the relevant entities somewhere else in modelspace, Flatten all to zero elevation, then (possibly use mapclean) and bpoly to create boundaries, then just pro rata the volumes in relation to the areas found