solid subtraction with other solids

[french]

hello to all:
I would like to know politely how I do to subtract a solid from another solid within the same set.
Thank you.

 

[DANI-3D]

Hi.
give an eye here:https://www.cad3d.it/forum1/threads/50406-rifilare-2-lamierethe problem is very similar

 

[320i S]

exact, identical solution also with normal solids (not sheets in short).