Did you check out

https://github.com/WillAdams/gcodepreview

Its based on openscad and it can help you to display the gcodes

On Sat, Jun 28, 2025 at 6:22 AM John David via Discuss <
discuss@lists.openscad.org> wrote:

On 6/28/25 01:48, Guenther Sohler via Discuss wrote:

If it works with gcode intended for Octoprint, it will probably work
even better with klipper, but klipper repositions some of the functions
for much faster speeds by moving the time wasting stuff off the printer
control board to an rpi4b or somewhat compatible clone, I've settled on
using banana-pi m5 variant, running a full armbian jammy desktop so my
printers gui is actually a big but cheap 23" or even bigger monitor. 
Connection is by usb-c from the rpi clone to the reprogrammed control
board at usb-3 speeds.  The gui is a web page, visible to and
controllable by any other machine on your local network.  My router does
NAT So I can run a browser to the rest of the world on my printers when
they aren't printing.

Cheers, Gene Heskett, CET.

"There are four boxes to be used in defense of liberty:
soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author, 1940)
If we desire respect for the law, we must first make the law respectable.

• Louis D. Brandeis

On Saturday, June 28, 2025 at 01:48:04 AM EDT, Guenther Sohler via Discuss discuss@lists.openscad.org wrote:

This runs in a couple of modes, and is fully programmatic (but that should be okay for folks on this list).

https://github.com/WillAdams/gcodepreview/blob/main/gcpdxf.py

is a basic Python file which will make a multi-colour DXF (uploaded a converted SVG version --- let me know if you have trouble making the DXF)

I'm currently deep into a rewrite which flattens out the (currently) ever deeply more nested CSG unions and incorporating better support for colour should dovetail well with that.

If someone would provide an example DXF file (where different colours are coded to different laser operations) and pseudocode for creating that file, I'll do my best to at least keep that in mind as I work on the re-write.

William

--
Sphinx of black quartz, judge my vow.
https://designinto3d.com/

William, gcpdxf.py
https://github.com/WillAdams/gcodepreview/blob/main/gcpdxf.py looks
interesting.  I will need to take a closer look at it.  I have been
focusing on SVG because I have other tools that worked, but at the time I
could not get the DXF to work properly.  But, I do not inherently care if I
use SVG or DXF for the format as long as the various interface option
(LaserGRBL, LightBurn, Inkscape, etc.) all play nice.  I will reach out to
you off-list about both providing 2D DXF test CAD files. I will probably
start with a quick-release jig fixture for the Falcon-2 - it would be nice
to have the lockable jig plates also have engraved rulers...

Gene, I'll put shoehorning a workflow into OctoPrint on to my ToDo list.
As far as I know, both LaserGRBL and LightBurn natively uses g-code. I
think it is more an issue of figuring out how to set up the configuration.

EBo --

On Sat, Jun 28, 2025 at 11:18 AM William F. Adams willadams@aol.com wrote:

On Saturday, June 28, 2025 at 07:18:42 AM EDT, gene heskett via Discuss discuss@lists.openscad.org wrote:

(re: gcodepreview)

Directly writing out G-code is something which I've pretty much shelved, mostly due to the tedium of coding up repetitive layers (and it turns out, my initial architecture wouldn't have been able to cope with that for CNC milling/routing).

Again, if someone wants to provide a sample G-code file for laser usage, I can add specific support for that --- but the program is extensible, so it should be straight-forward to implement.

William

--
Sphinx of black quartz, judge my vow.
https://designinto3d.com/

I had never heard of Metapost.  I'll have to take a look at it. That said,
skimming your article I saw it mentioned iTex amongst others.  That is way
cool.I will have to read this carefully.  As a note, I was one of Gerald
Farin's CAGD students for awhile.  We should try to make some time and geek
out ;-)

On Sat, Jun 28, 2025 at 1:34 PM William F. Adams via Discuss <
discuss@lists.openscad.org> wrote:

On Saturday, June 28, 2025 at 02:12:42 PM EDT, John David ebo.2112@gmail.com wrote:

It is a re-working of METAFONT to make PostScript.

Note that that is something of an insider reference --- it was from Dr. Knuth's "Earthshaking Announcement" at TUG:

https://news.slashdot.org/comments.pl?sid=1702818&cid=32752126

https://tex.stackexchange.com/questions/19079/what-on-earth-is-itex

https://www.johndcook.com/blog/2010/10/04/serious-lessons-from-knuths-joke/

Currently reading some of those books.

William

--
Sphinx of black quartz, judge my vow.
https://designinto3d.com/

On 6/28/25 13:34, William F. Adams via Discuss wrote:

Particularly if using LinuxCNC to drive the machines, the transition
from printing by layers to milling and routing is a nearly vertical
learning curve.  LinuxCNC does loops  many times better than any
slicer.  The net result since I learned LinuxCNC decades ago is that I,
as a hobbyist, did not really want to learn what became FreeCAD, which
has a near vertical learning curve, looked at ALL the *CAD programs but
wanted to do what the machine could, so I write my own gcode. So that's
become 2nd nature for me.  That wasn't so vertical, and it has all the
loop constructions needed, along with really good documentation.  So one
can finish a feature, then lift and move to the next one on a mill or
lathe.

I have a routine that sharpens a 10" carbide tipped table saw blade far
sharper than a new one, takes a Dremel strapped to a mills head, and a
rotary table addressed as C axis, 3 days to run to completion as the
diamond disks touch to the blade is quite light so as not to flex the
disk, you can see the carbide dust drifting away in the air currents in
good light, its that fine. Its 90 lines of g-code.  That could not be
done on a printer w/o unrolling all the loops, making the slicers output
into gigabytes of code. Most of which is 25kb chunks of repeated by the
layer g-code with a single one byte variable changed, the height of that
layer.  That pains me, but that is how printers work. It's an additive
process, where the mill/router and lathe are subtractive.

That diff changes everything.  It serves a printer by doing what its
limits can do, very well.  but it does so by multiplying the amount of
g-code, sometimes by 1000 or more because it has to deal with layer
after layer of the additive process.  You or I cannot do that w/o 100's
of typo's.

The possibility of using the laser wire welder hardware as an additive
maker has an attraction here.  Someone should build it. LinuxCNC can
handle up to 9 axis's of movement. All simultaneously. It can compensate
for way wear. It can control anything that can be moved to sub micron
accuracy. My lathes do not have compounds or taper attachments. LinuxCNC
does all that.

Cheers, Gene Heskett, CET.

"There are four boxes to be used in defense of liberty:
soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author, 1940)
If we desire respect for the law, we must first make the law respectable.

• Louis D. Brandeis

On 6/28/25 12:42, John David via Discuss wrote:

Generally that assessment is good. I'm in favor of klipper, which
replaces both merlin and octoprint, with something that to me is
reconfigurable and a lot easier to extend to make the printer into a
send it a file, go get the part work flow. No baby sitting during the
warmup to clean nozzles and such. I've made the printer do that by
itself. My biggest problem is time, at 90 I'm running out of time to do
the things I can dream up.

Cheers, Gene Heskett, CET.

"There are four boxes to be used in defense of liberty:
soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author, 1940)
If we desire respect for the law, we must first make the law respectable.

• Louis D. Brandeis