I'm a bit confused by some calculations for cut and fill that Vectorworks is giving me - this could of course be my own ignorance on the subject!
In the attached going from the bottom up, the first site model slopes steeply and I want to level it out. The second is the site model with a spoil pile modifier at elevation 480 on the left of the model and it gives me a cut volume of 0 and fill volume of 28.03m3. In the 3rd image, I've used a pad modifier over the whole site at an elevation of 480 and it gives a cut volume of 13.477m3 and fill of 12.582m3 with .895m3 left over (26.954 m3 total). The top image is the 2d model. Why the discrepancy? Which modifier should I be using to work out how much to spread and how much to remove as this has obvious cost implications and I want to get it right.
Site Models.pdf