On Wednesday 21 April 2021 13:16:58 A. Craig West wrote:

I didn't have laser cutting in mind, Craig, more like a suitable carbide
end mill whose dimensions would have to be known by the slicer. Or
assume sinker EDM, but that also has problems due to the erosion of the
sinker electrode as it works.

That too is a major problem when the hole being burnt is more than
electrode diameter deep. I have cut slots to make compressible petals
out of a socket to receive a ball screw, with tapered threads on the
outside.  It does those slots an inch deep, .032" wide, putting a drive
shaft on the end of a ball screw for 2 lathes x drives now. No warpage,
no burrs, puts tons of grip on the end of a ball screw when its wet with
threadlocker and the nut drawn tight.  Hasn't slipped a micron in many
years. That was the general idea.

So what to we have that can turn an openscad output into gcode?
Preferably metric based although linuxcnc accepts either measurement
system.  Preferably something smart enough to make use of linuxcnc's
looping abilities. Something that turns 100 lines of source code into
100 gigabytes of gcode because it has to unroll all the loops, is not to
me, a workable solution.  Success to me is a 90 line gcode program that
takes 3 days to run. I have done that by hand. It also made the sharpest
table saw carbide blade I've ever used.

So I am curious, if you are designing a part in openscad that will
eventually be made on a cnc controlled 3 or more axis milling machine,
what do you use to make that connection work?

Thank you all.

[...]

Cheers, Gene Heskett

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

• Louis D. Brandeis
  Genes Web page http://geneslinuxbox.net:6309/gene

On Wednesday 21 April 2021 13:38:58 Alex Gibson wrote:

I got many and confusing hits on that, exact URL please?

Cheers, Gene Heskett

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

• Louis D. Brandeis
  Genes Web page http://geneslinuxbox.net:6309/gene

I use PyCam to convert OpenSCAD to gcode that I then run on LinuxCNC to
drive my router.

On Wed, 21 Apr 2021 at 19:37, Gene Heskett gheskett@shentel.net wrote:

Thanks for all the replies,

My method is basically import a 2d dxf into the cam software, select the
boundaries, and profile or pocket as required, either remembering the
depths of cut or otherwise. A 2d dxf from openscad does the job, but to
get the boundaries, it is sometimes necessary to difference shapes
purely to get boundaries. It came to mind, that it would be simple to
quickly check the shape of the object by extruding downwards, in the
similar way as I think of the machining action, and the depths could be
extracted for use in the cam program. Mirroring would work, but then I'd
have to be thinking 'upside-down' so to speak. I'm not sure of the logic
behind not being able to extrude downwards, I would have thought it
would be not difficult to allow that. A bit more fiddling, and could
probably use offset to generate the tool path for cylindrical cutters,
but the cam does that fine, if I get the outlines.

On 21/04/2021 18:16, A. Craig West wrote:

Hi Gene

I'm not surprised, there were several plugins with similar names that evolved from one another.

This is to my knowledge the best version, definitely works, and takes the best bits from the others - so is the one I'd recommend.
https://github.com/brad/Inkscape-OpenSCAD-DXF-Export

I've validated the install instructions on Windows and Linux - basically just copying files into Inkscape's extensions folder.

With it installed you can open Inkscape, draw or import something, then just need to make sure you've done a 'convert object to path' and then 'save as' and choose the option OpenSCAD DXF.

Good luck!

Alex Gibson

admg consulting

edumaker limited

• Project management
• Operations & Process improvement
• 3D Printing

-----Original Message-----
From: Gene Heskett [mailto:gheskett@shentel.net]
Sent: 21 April 2021 19:37
To: discuss@lists.openscad.org
Subject: [OpenSCAD] Re: Linear_extrude

On Wednesday 21 April 2021 13:38:58 Alex Gibson wrote:

I got many and confusing hits on that, exact URL please?

Cheers, Gene Heskett

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

• Louis D. Brandeis
  Genes Web page http://geneslinuxbox.net:6309/gene

OpenSCAD mailing list
To unsubscribe send an email to discuss-leave@lists.openscad.org

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On Wednesday 21 April 2021 17:16:32 Alex Gibson wrote:

That machine, since its a new buster install needed another 6 gigabytes
of stuff installed to get rid of all but one dependency error in the
extensions-error.log. From that log:

Extension "Win32 Vector Print" failed to load because the extension is
designed for Windows only.  This is caused by an improper .inx file for
this extension.  An improper .inx file could have been caused by a
faulty installation of Inkscape.
Extension "Sketch Input" failed to load because a dependency was not met.
Dependency:
type: executable
location: path
string: skconvert

LaTex was also missing, but roughly 5GB of texlive stuff seems to have
satisfied that. LaTex support seems to be on its way to the dustbin of
history anyway.

skconvert is still missing and despite the error msgs above claim that it
indicates a faulty windows install, everything on that machine is either
an AppImage or came from the buster repo's. skconvert is apparently a
windows utility to convert sketchup files to something inkscape can use.
I promise I won't miss it. :)  Sketchup if you recall history was a free
google offering, but was converted to a windows only app for seat fees
by google. Obvously I've not a copy of it on any of my farm today.

Now, for my 86 yo wet ram to see what it can do for openscad.

However, in my messing around I did crash inkscape as it stopped
responding and I had to do another login from a different workspace and
issue a killall inkscape.

Thank you Alex Gibson for that link.  Its been an interesting 3.5 hours
of installing stuff.  The net seems a bit slower tonight. But I am
getting the bandwidth I'm paying for.

Take care and stay well folks.

Cheers, Gene Heskett

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

• Louis D. Brandeis
  Genes Web page http://geneslinuxbox.net:6309/gene

On 21/04/2021 23:29, Jordan Brown wrote:

The following code may explain the overall awkwardness of my efforts

translate([400,0]){
difference(){
linear_extrude(30)square(250,true);
linear_extrude(20)circle (100);
linear_extrude(50)circle(50);
linear_extrude(50)translate ([0,80]) square(25,true);
linear_extrude(50)translate ([80,0]) circle(20);
}
}

// 2d conversion.

difference(){
square(250,true); //block 250square by 30
circle (100); // bore 20 deep
}
circle(50); // bore right through
translate ([0,80]) square(25,true); //bore right through
translate ([80,0]) circle(20); //bore right through

The first block of code shows the shape of the object (It is not too
difficult to draw it upside down). the linear_extrude values are the
depths of the pockets/profiles (-z values). To convert it back to 2d for
exporting as dxf, requires differencing some items. On this simple made
up example, it is not much of a problem, but it certainly would be for a
more complex item. (move the small square to [0,90], say. I would like
to be able to produce the 2d drawing (my initial starting point) without
fussing with differences, etc, and simply add some linear-extrudes with
depths, to get a quick look at the solid object.

The starting point would be from the 2d dimensions, a hand drawn sketch,
say.

The following is much easier to write, it complies with 2.5 d thinking,
and the the concept would work on polygons, or other 2d shapes. It is
all constructed from 2d and extruding, but There is no straightforward
way to convert it to a dxf file within openscad, afaik.

module xyz(x,y,z){
    linear_extrude(-z)
    translate([x,y])children();
}

intersection(){
difference(){
    xyz(0,0,-50)square(200,true); // work piece
    // pockets
          xyz(0,-30,-50)circle(20);
          xyz(0,0,-50)circle(15);
          xyz(20,0,-30)circle(20);
          xyz(0,0,-20)square([100,50],true);
     //island
    difference(){
          xyz(0,60,-20)square(40,true);
           xyz(0,60,-20)circle(10);
    }
 }

 // profile   (intersection with object)
   xyz(0,0,-49)square(195,true);
 }

On 22/04/2021 13:14, Ray West wrote:

On 4/22/2021 11:42 AM, Ray West wrote:

I think you have the signs wrong; you negate Z here but then you supply
negative values below so the result is positive.

I'm going to assume that you only intended one negation; you want to
drill holes down from the Z=0 plane.

So why doesn't this do what you want?

module xyz(x,y,z){
    mirror([0,0,1]) linear_extrude(-z)
    translate([x,y])children();
}