How to calculate material removal volume

I need to find out the material removal volume for turningparts during processing.
Basicly, this can be done by building a stock outside (cylinder)and substracting the part volume from the stock volume. The part'svolume can be calculated using mass properties.

Do you know
1.how to build a stock which can include the parts and
2.calculate the removal volume using API and VC++?

Thank you!SolidworksApi macros