first off, i have catia v5, and know how to design on it, but i do not know what its machining capabilities are. if i were to get a bridgeport mill would i need a DRO or cnc module. also, would i need an intermediate software package like mastercam to have cnc capabilities, or can catia do that? also, what are you suggestions for a good used mill and suggestions for a module? im just getting interested in this stuff, help me out if you can. thanks for your time
lou

DRO would be useful for manual milling. So Catia is a CAD package, I believe it also has a CAM capability. If not then you would need a CAM package.

If you're looking for a large mill stick with Bridgeport or one of the Bridgeport clones. If possible get one with ballscrews where your CNC conversion would be the addition of some Servo or Steppers and the drives for those motors.