Splitting an object into two

 From:  Frenchy Pilou (PILOU)
12046.4 
Boolean DIff ?
Right Click for Done
Click Volume not wanted
Press Key Delete (or red X) for kill line + volume not wanted in the same time!

For a cylinder take a diameter! ;)
For a complex object take a plane (or an extruded line/curve )

EDITED: 21 Jul 15:33 by PILOU