FreeCad tool chain

I am considering tinkering with FreeCad. Like I need something more on my plate.

Here are a few toolchain questions as I have not downloaded it yet:

  • Does it have a tinyG post processor?
  • Does the post-processor support Laser diode modules on a tinyG driven CNC
  • What companion software do you use for machine control (I currently use chillipepper)?

I don’t have many answers but might be able to help launch in the right direction…

Here as the posts available in Path in FreeCAD 0.20 — except for “mygrbl” which is my own local hacked copy of the grbl post.

@JustinClift did you ever make a g2 post processor?

Or did you modify the LinuxCNC post to take g2 / tinyg options? I don’t see anything in FreeCAD/ at master · FreeCAD/FreeCAD · GitHub — does the linuxcnc post just work, maybe with some general arguments?

I don’t know about laser diode support in post.

I use UGS and Candle as senders.


Nah. I gave up on FreeCAD when I started getting past trivial designs and needed to put things together using Assemblies. Instead of having a single Assembly approach that works, they have multiple different competing Assembly plugins. Completely incompatible with each other, and if you choose one then you can’t use the others. Also none of which are officially blessed and likely to have support in x number of years.

I can’t put into non-sweary words just how much that makes their entire project useless, at least for my purposes. :frowning:

Hopefully they solve that problem, and have a single, working “Assembly” solution in the future that eveyone can use. Not holding my breath though. :frowning:


From rough memory, one of the existing posts did work anyway. Not sure if it was the LinuxCNC one, or maybe it was a GRBL one. No longer sure. :slight_smile:

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I agree it’s been an inconvenience. One of the upsides or downsides, depending on your perspective, is that different FreeCAD contributors have tried different ideas out. I would be surprised to see older Assembly workbenches thrown out, making old documents unusable, but I would hope that they would at least get to the point where one particular approach is integrated, recommended, and thoroughly documented…

Assembly3 depends on SolveSpace which is not license-compatible, so it’s unlikely to be blessed as The One Assembly Workbench unless all the constraint solving is re-implemented internally. At least it no longer requires running a fork of FreeCAD like it used to!

The nice thing about constraint-based assembly is that it’s like making sketches. The bad thing about constraint-based assembly is that it’s like matching sketches. In both cases, if you add a constraint that it has trouble solving for, it makes up nonsense. I don’t know if I’ve gotten better at avoiding nonsense in sketches or if FreeCAD constraint solving in sketches has gotten better over the past few years. Fundamentally, finding solutions won’t improve in Assembly3 without improvements in SolveSpace. The experience using Assembly3 is a lot like SolidWorks in my experience, both in the mechanisms of constraint and in the fact that sometimes the parts just do something I don’t expect and I have to puzzle out how to get them to behave.

Assembly4 looks promising and doesn’t need a solver, which makes it remarkably more efficient. It does require adding local coordinate systems to pieces to map together if they don’t map at the origin, or at least it works better that way, not needing to set offsets from the origin.

Compared to SolidWorks, I like that Assembly4 (at least; I don’t remember about Assembly3) lets me build both parts and assembly in a single document (vs. .SLD / .SLDASM in SolidWorks).

Assembly4 clearly could use more refining and documentation, and trying to understand how to use it from the documentation and the single mega-thread on it on their forum is a bit frustrating. The maintainer is still tinkering with what to call the top-level objects. But the idea of explicit assembly instead of constraints makes a lot of sense to me.

Ultimately, I like the idea of being able to try different ideas, but it sure would be nice if there were one recommended assembly.


I’ve been using FreeCad for a couple of years. Not really that great at it, but I use in occasionally to make some parts and mounts and stuff. I recently was watching some tutorials and used an assembly plug-in called A2plus. Seemed to work ok for the tutorial I was doing. Again, its the first time (yesterday actually) I’ve ever tried any assembly in FreeCad. Just thought I’d mention it.