[OpenSCAD] DXF for cut and engrave

Rogier Wolff R.E.Wolff at BitWizard.nl
Thu Oct 24 06:49:53 EDT 2019

On Thu, Oct 24, 2019 at 10:56:15AM +0100, nop head wrote:
> The problem is a laser doesn't cut a line with zero thickness but people
> pretend it does.
> You can model any object a laser can produce in OpenSCAD. What is needed is
> a CAM stage for lasers that creates the tool path, just as 3D printing and
> milling. For some reason the CAM stage is ignored when laser cutting.

The CAM stage traditionally happens in the printer driver under
windows. A program, ANY program tells windows it wants to print
something. Then together with some confguration, the printer driver
translates e.g. the color of the line into different commands for the
laser (say: red: "all the way through at 100% laser power and 10%
speed, blue: "just a scorched line at 50% laser power and 100%
speed", green: "engraved in bitmap mode").

The problem is that with those things tightly coupled to the laser
device in question, and them being closed source, it is difficult to
optimize those things. For example, at my friends' the laser will
easily cut up a single "rounded box" outline into 4 lines and for
quarter-circles and do them in the woarst possible order you can

Optimizing the toolpath is equivalent to the travelling salesman
problem and therefore NP complete. But that doesn't mean you can't do
a meaningful optimization. An easy optimization (that 3D printer
slicers should also do!) would be to always pick the closest
linesegment. In the rounded-box example that immediately leads to the
optimal solution. Then as a post processing step, investigate the
longest non-cutting moves and see if you can improve on them. Take a
segment between two long-moves and try to insert it in the path
somewhere to see if the total non-cutting path length can be reduced.

Sorry for my rant. 


> On Thu, 24 Oct 2019 at 09:39, Troberg <troberg.anders at gmail.com> wrote:
> > OpenSCAD mailing list wrote
> > > On Tue, Oct 22, 2019 at 11:10:03AM -0700, WillAdams via Discuss wrote:
> > >>I have probably missed part of this discussion, but for me: I use
> > > openscad to design a box for a project in 3D and then I lay the pieces
> > > flat and send the outline to be laser-cut.
> >
> > OpenSCAD is heavily oriented towards 3D-printing, and, to some extent,
> > leaves us laser cutter guys out in the cold, or at least requiring us to
> > make irritating workarounds.
> >
> > For example, a line is useless in 3D-printing, but extremely useful in
> > laser
> > cutting (google "living hinge" for a good example).
> >
> > I really hope that considerations for laser cuttings will enter into the
> > plan for OpenSCAD, it would mean a lot to us. 3D-printing is just too slow,
> > has too small work area and too limited in materials available to be useful
> > for me.
> >
> >
> >
> > --
> > Sent from: http://forum.openscad.org/
> >
> > _______________________________________________
> > OpenSCAD mailing list
> > Discuss at lists.openscad.org
> > http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org
> >

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** R.E.Wolff at BitWizard.nl ** https://www.BitWizard.nl/ ** +31-15-2049110 **
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The plan was simple, like my brother-in-law Phil. But unlike
Phil, this plan just might work.

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