While not in the same realm as some of the more expensive software mentioned CamBam now has a Linux port that runs Linux native, (not under an emulator). It will work with 3D geometry (STL or 3DS), but it deosn't have any real 3D CAD capability. I use it all the time for 2D CAD. (I use ViaCad on a Windows machine for 3D).
It doesn't do REST, HSM, or TRACHOIDAL, but it does generate accurate tool paths from 2D geometry, and pretty good ones (depending on your set resolution) from 3D geometry. It also has the most proactively helpful user group on their support forums of any forum I have ever seen.
Currently I have CamBam installed on a Windows box and a Linux Box side by side. It was a little bit of a pain to get the support libraries and install them on the Linux box, but I attribute that mostly to the fact that I am a novice Linux user. There are a few things using the ALT key that conflict with the standard Linux useage, but none that are not able to be dealt with.
It has a number of standard post processors, and its fairly easy to modify a post if needed. It has stock posts for EMC and Mach. I still have not gotten around to testing the EMC one, but the Mach one serves my Mach needs without modification. Tool changes, spindle control, etc all work like they should. Sorry, I still haven't gotten around to converting one of my machines to LinuxCNC, so I have not tested the EMC post. There are hard corps Linux users on their forum though that you could ask.
Its core is just 3 axis, (wadda ya expect for the price) but every machine operation has the ability to manually add G-Code before and after. If you have a 4th axis that you use for coordinated movement while machining this probably won't work for you, but if you have a 4th axis that you primarily use for indexing (like I do) you can always add a G00 AXXX at the beginning of the machine operation so it will be embedded in your code file when you generate code.
There are some turning applications, but that part is really just alpha or pre-alpha in my opinion. Your mileage may vary. There are guys using them.
It boiled down to this for me. Its CAM package that works and I could afford.
~~ Sorry. I didn't see your post when I first made mine.
submicro wrote: I have yet to find a CAM program that I really like. But for now I use CamBam. They have a linux version which works well, and the price is reasonable.
What I still have an issue with is getting a decent, affordable, modestly short learning curve, 3D CAD program running under Linux.
inkscape Gimp ..... ALLof this will work on the item it is made for
