I'm in the process of designing my laser right now. I built a CNC milling machine (not router) a few years ago and used EM2 with CAMBam and then moved to Mach3 and CAMBam. I did enough with it to justify a much larger commercial CNC milling machine and use Mach3 and VisualMill/VisualCAM with it on a weekly basis. I consider myself pretty good at creating something in CAD and then generating g-code from it to then mill up in aluminum on the machine. If you've looked at my design thread in the general forum, all of those pics are things I will cut on my mill. I'm actually prototyping a bit of it this weekend in fact.
I have to be honest, I think people using g-code for a laser cutter are crazy if they can afford a DSP (don't get me started on GRBL w/Arduino
). I feel that r691175002 is 100% correct. G-code is powerful and capable. It's also a rather significant tool chain step that really slows down the use of a laser cutter. The process of drawing the image, going into a CAM program to annotate and generate g-code, then going into a controller program (EMC, Mach3, etc) to run the g-code is a pain in the butt. Revisions require a re-export of the CAD file unless you've got a very expensive "continuous-integration" setup OR you are drawing in the CAM package which can be very painful. I've spent well over 1000 hours using my big mill and I can tell you that once you really get into it, every step in the process becomes a burden. I recognize the need to use g-code on my mill because it does far more sophisticated things like 3d machining, tool compensation, ramping-in and out of cuts and holding tabs, re-machining, etc. I need the low-level abilities it supports. There is a fair bit of overlap between a laser cutter and mill/router at a low level but you add a lot of overhead to support using the same tools on both. So then people try and automate things by using good 2d CAM packages like Vectrix Cut2d which simplify 2d-only cutting as much as possible. The reality is that a DSP has all this built-in already and does a dang good job of it. A DSP is NOT as capable as a CAD/CAM system, but a great laser cutter is still far simpler and less capable than a 5-axis mill too. Less capable then even a 3-axis router.
Whew, long winded way for me to simply say - use the right tool for the job. Succinctly: in my opinion g-code is not ideal for a laser cutter, not because of the g-code but because of the tool chain and work flow.
-Mike