In this dialog you order the volume calculations you want to perform. The volumes are calculated with the perimeter and base as a closed solid volume.
You can choose whether you want to use the design base or the theoretical base in the volume calculations.

In the “Volume Intervals” table you can define several chainage intervals for volume calculations. These intervals could be fully or partly overlapping.

For each interval you can choose separate offsets for the perimeter and base. This is very useful. If you for instance want to calculate the volume of the tunnel wall, then you can just make two interval lines in the table and insert the wall thickness as an offset for the perimeter in one of the lines. If you want to calculate the surface of the wall, then you can just divide the the wall volume by the wall thickness.

Tip: If you want to calculate the volume of the closed drainages, then you make the design base follow closed drainages, make one calculation with design base and one with theoretical base and withdraw the results from each other.