How do you get the 3D model into the CNC machine

I've been threatening myself with thoughts of building a small 3 axis CNC machine for a few years now. Although I've done some research on it, I don't understand what software takes a 3D model and spits it out to control the motor circuitry?

I'm hoping that some kind soul will help me get this concept, it's the last part of the machine that I need to know about before I can start. I've seen lots of instructables on building the CNC machine, but am struggling to find any info on the control software.

Here is the 3 axis CNC process as I understand it , please correct me if I'm wrong:
1. Model is designed using software like Blender, 3Dmax, and so on
2. ??? Magic software takes this model and translates it into tooling paths
3. ??? Magic software converts tooling paths to control pulses. These pulses are sent over the parallel port.
4. Control circuitry receives the control via the parallel port and sends pulses to the coils of the stepper motors, moving the tool carriage and cutting the model.
5. Much rejoicing.

Bonus Question
Parallel ports are lame. How could I use a hip young USB port? My best guess is that the magic software can be configured to spit out over a usb port, and then an Arduino could be used to receive and process it into pulses for motor control?

Extra Super Bonus Question
What's a "G-Code" and where do I get one?

Thanks in advance for any light you can shed on this!

2) Magic software like CamBam.
3.) Magic software for appropriate machine might be Mach 3 or LinuxCNC
Tomdf (author)  steveastrouk5 years ago
Sweet, thank you for pointing me in the right directinon. I'm off to go research. Woosh!
Tomdf (author) 5 years ago
Ah, ty, how did I miss that? The haze is beginning to lift!
caitlinsdad5 years ago