Quuestion for cad cnc guys

[pinolelst]

Forgive me but I'm intrigued by this process and have a few questions...
Do you design in one application and use another to generate the code for the machine that dictates milling parameters ?? Or is there one application that does it all.Can I use Solidworks for instance to design and generate the milling data (G-code??) within that application ??
Do you design only in a dedicated modeller and then use something like mach3 cnc to generate cuts and steps code for the cnc mill ?
Once you have the code do you simply plug into the cnc mill via computer and push "Start" once you've got the workpiece zeroed out I assume so the mill starts in the physical world at the same point as it does in the 3d world??

Thanks in advance

pinolelst