Welcome to Mach3 menglor:
Starting out in CNC machining today is much easier than in the past, where it was necessary to learn G-codes and link them together into a program; test run the program cutting air to detect any major mistakes you very likely made, such as trying to cut the vise in half, before committing the cutter to metal. Many shops made a part from wax or high-density foam before actual machining. A misplaced decimal point or typing “4” instead of “3” could mean disaster. The amount of time to produce a working, final CNC program was agonizing, and mentally exhausting.
Advances in computers, i.e. high speed processors, massive memory, color graphics, CAD/CAM programs and variants of CAD changed the world of machining forever. Today you can watch your program gobble away a "virtual" chunk of material, transforming it into your part using all the cutters and drills you chose. And the best part is you can do more work, in a tiny fraction of time and expense than ever before, and see it all “Virtually” before you cut actual material.
CAD programs besides making a drawing, output DXF files for a shape, or holes/pockets/bolt hole patterns quickly and accurately. The CAM program reads the DXF file, and outputs your G-code.
For CAD drawing I use DraftSight, an absolutely fantastic free CAD program, produced by the makers of Solid Works, Dassault Systemes, of France. Solid Works is a high-end, world class program. There is a learning curve to all CAD/CAM programs, but is time well spent if one is serious about doing CNC machine work.
There are many good CAM programs to produce your G-code. Personally, I like CamBam and CutViewer, partly due to price, but there are many to choose from. CamBam has a 30 day free trial, a forum, very thorough Help file with graphics, and a post-processor tailored for Mach3. CutViewer, also with a free trial entry, works from within CamBam, enabling you to jump back and forth, and edit until you like what you see. In CutViewer, your "virtual" material can be crashed into, cut in half, or otherwise destroyed, but the program will stop and show you where the code line is, no matter how many thousands of lines of G-code into the program it happened. You can measure any section of a finished “Virtual” part, zoom in to see a detail, speed it up, slow it down, to see every move a cutter makes.
Mach3 has built in "Wizards", created over the years by knowledgeable Mach3 users and donated to the community, that can perform many common functions, and write the code directly into a Mach3 program, creating the G-code for you; answer the prompts, and run it on the screen before cutting anything. Pockets, drill patterns, keyways, arcs, face milling etc.
The "Mach3 Addons" are licensed wizards for $50.00, which are more refined than the freebies, with a similar look and feel. Log onto the "new" website advertised at the top of the Mach3 Forum page.You can do multiple kinds of routines with multiple tools, and they are linked together into one single program automatically. You can create a complex machining operation involving many tools in minutes!
The "Mill Wizard" is another stand-alone program of wizards, licensed at $75.00. This is a variation of the Addons, with more advanced features. Both of these wizards have their place in the family. Both of these programs and the free wizards are opened from within Mach3.
The wizards are not sold as “CAD/CAM" programs, but actually are for machining frequent tasks, i.e. drilling bolt patterns, facing, pocketing, slotting, keyways, arcs, circles, etc., and can be zoomed, rotated, tested "virtually." The writers have demos, and step by step pages you can study on the site.
There are lots of "freeware" CNC programs out there on the internet, but in my opinion the Mach3 wizards and licensed wizards are superb, worth every penny, and won't strain the budget. They are fast, accurate, very intuitive to use, and well thought out. The amount of finished G-code cranked out in seconds is impressive.
When you get deeper into CNC, there are more powerful 3D CAD programs available, at much greater cost of course. Engraving, photo artwork, lithophanes, 3D/ 4-axis carving, are all doable with Mach3 and home shop machines.
John