Pilou thank you in advance.

As you said , I made three separate blocks ( each one is a single group ), than what ?

Next step is to group them again ?

I do not understand what next .

I made a simple model in SU . The purpose is to move a block with an bend hing road passing trough its slot , just like a crank mechanism .
I tried everything, but I could not move it the right way.
Can somebody help me please !

T.I.A.

Franky

Example