Database Software

Hi

I have a consistent RMAN backup.I wanted to restore it to another server.my goal is replicating exactly what i have on my server to other.I dont require duplicate command..its just a question of asking why what i have done is not working .Rather why this procedure is not working.
Steps follwed are Restored entire database.
Now I have verified checkpoint_scn in controlfile and datafile headers are exactly same.So no Media recovery required.While recovering databsae is is asking me to use backup controlfile and while opening database it wants me open RESETLOGS.
When Checkpoint_SCN is in sync everywhere and i dont change db_name ,why it asks for RESETLOGS.Rather how it or where from it come to know that controlfile is restored.
I thoght may be REDO log files are not present so it might have identified.I have REDO log file copies so i copied and tried but same thing happened..RESETLOGS

if i copy datafile,controlfile and REDO logfile with OS command,i a
was not aked for RESETLOGS or backup controlfile while recovery and open database.
But in case of RMAN why and how it asks for RESETLOGS.I have everything in place as it is but why shoul i do RESETLOGS.