getting volume of Mesh relative to a plane

[Ingsayyad]

I want to get the volume of a mesh relative to a plane with different heights. e.g.,

The volume is of a box relative to the plane (under) with different heights (.05 m steps). Is it possible to do it with a script?

[daniel]

Ah ah CloudCompare is bad with meshes ;) I don't see how to do that properly with CC...