Calculate Volume

[jbrhwy]

Request suggestions on how to get VW to calculate volume of excavated base material (a pay quantity).

Paved airport taxiway with variable slope: Pavement removed (variable depth), unsuitable base material excavated (variable depth & area). COGO survey undertaken to pickup bottom of pavement & top & bottom of base excavation areas, survey points imported as stake objects.

[Chad McNeely]

Sounds like it would be possible with two DTM surfaces, say existing for the bottom of the fill and proposed for the bottom of paving/top of fill.

The guy in charge of Landmark says that 2009's cut and fill calculations are now reliable. I think it would be a good idea to manually check at least a subset of the volumes, just to satisfy yourself that VW wasn't being silly.

If the volumes don't compute correctly, the two-DTM approach might still be useful. Once satisfied that each DTM surface is reasonably representing the surfaces in your survey, you can manually cut a bunch of sections through them, trace the area between the DTMs, and multiply the area of each traced poly by half the distance to its neighbors, or use Simpson's Rule, to get an interpolated volume. With some classing of the area polys used, a worksheet might be a little helpful.

[jbrhwy]

Chad

Problem right from the start, even through the existing site model was clipped with a valid closed polygon (Boundary Object) the "Projected Area (Existing)" is shown the same before & after the boundary object added.

[Chad McNeely]

I have no idea what the area reported in OIP for the Site Model refers to, I've never dug around to see.

While the data might be suspicious already, the area of the Site Model isn't necessarily related to the cut or fill volume of the area you modify. You can ty a simple test, say a small pad or site modifying 3d poly, with a tight fence to get a nearly cubic excavation, and see it the cut volume nearly matches the cube volume. I still can't believe after all these DTM releases that this wouldn't at least occasionally work...