I get text out of OpenSCAD by using echo and the command line and capturing
it with a Python script that extracts the text from the echo format. There
is no access to the geometry coordinates though unless you generate it with
polygon, etc.

On Tue, 11 Aug 2020 at 14:18, William F. Adams via Discuss <
discuss@lists.openscad.org> wrote:

I would find general file io to be VERY useful, it would allow me to
write code to support file type we don't currently support, for both
input and output

On Thu, Aug 13, 2020 at 10:20 AM William F. Adams via Discuss
discuss@lists.openscad.org wrote:

I am actually more interested in arbitrary file input, but both input and
output would be useful. Must of my libraries work entirely in userspace, so
I have all of the co-ordinate already

On Thu, 13 Aug 2020, 11:43 Jordan Brown, openscad@jordan.maileater.net
wrote:

Hi William, I've not followed this whole thread, but if you want to cnc
finger joints, I would not start with scad. What cutting tool will you
be using, and what is the material? What tolerances are you looking for?
Unless you intend standing the pieces on edge, you will not get square
corners profiling them with a router bit, although if in wood, with a
small diameter bit, woodfiller can solve that. If you are using edm,
plasma, laser or waterjet, then that will require a different solution,
depending on how thick the material is too. The tricky area is the
interface between theory and practicality. It would be relatively
trivial to 3d print it, if it was just a proof of the model you were
looking for - But you'd most likely have to take into account tolerances
again.

Best wishes,

Ray

On 13/08/2020 18:54, William F. Adams via Discuss wrote:

You can get close with include <>, if you wrap the data with "file1=[" and "];"

You would need to format to suit.

From: Discuss [mailto:discuss-bounces@lists.openscad.org] On Behalf Of A. Craig West
Sent: Fri, 14 Aug 2020 01:55
To: OpenSCAD general discussion
Subject: Re: [OpenSCAD] Potential uses for writing out text files from OpenSCAD (was Re: Managed to
model a finger joint box with relieved fingers --- now how to actually cut it? Allow OpenSCAD to
write out files?)

I am actually more interested in arbitrary file input, but both input and output would be useful.
Must of my libraries work entirely in userspace, so I have all of the co-ordinate already

On Thu, 13 Aug 2020, 11:43 Jordan Brown, openscad@jordan.maileater.net wrote:

If you want to experiment with writing other file types, it's not too hard.  Use echo() and
copy-paste the output, or run OpenSCAD from the command line and capture the output.  You'd have to
post-process it a bit to remove the noise, but it wouldn't be terribly hard.  nop head does this to
generate BOMs.  I do it to generate lists of models from multi-model files.

But make sure that you can actually do what you want before thinking about adding new features.
Remember that nothing in the OpenSCAD language has access to the coordinates.

translate([x,y,z]) {
/* Nothing here has any way to access the the new origin in global coordinates. */
}

If you want access to the coordinates you'd have to do your own transforms in parallel.

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Ray West wrote:

Apparently.

It's the CAD tool which I prefer to use --- and I've modeled fingerjoints in it before:
https://community.carbide3d.com/t/cnc-finger-joint-box/8880

I am planning on using a 1/4" square endmill, a 1/16" ball-nosed tapered endmill, and a 1/4" radiusing endmill.

Tight enough for a void free joint.

I created a fixture for doing that:
https://cutrocket.com/p/5cb25f3380844/
and I've cut boxes thus:
https://cutrocket.com/p/5cb536396c281/
It's a tedious pain.

The refuge of the incompetent woodworker --- I'm trying to design a joinery system where joints have no visible voids --- hence the radius endmill which I intend to use to relieve the fingers to match the radius left by the 1/4" endmill. See the images at:
https://community.carbide3d.com/t/design-into-3d-boxes-magazine-storage/16238/54
and
https://community.carbide3d.com/t/cnc-finger-joint-box/8880/113
and
https://imgur.com/g9pQxS6
William

Hi,

Use scad for showing the picture, but imnsho, you would be better off
generating the gcode separately. I've attached a screen shot of a simple
box generator - no cad used whatsoever. The joints are not finger
joints, but are a sort of stepped butt joint, modern glues are stronger
than the wood.

I'm not sure if you need the ballnosed bit, or the tapered bit. Tool
changing is a pain, unless you have some high end machine, or possibly
designing a machine specifically for making finger joints. I've used 
cutters similar to this, quite successfully for wood carving, which sort
of combines a taper and a ballend.
https://www.amazon.co.uk/SpeTool-Tapered-2-Flute-0-25mm-Coated/dp/B077883PDW/ref=sr_1_13?dchild=1&keywords=tapered+milling+cutter&qid=1597401368&sr=8-13

I'm guessing you have a sort of flatbed cnc routing table, and you do
not really want to have to change tool bits, or manipulate the sheet
which you are machining, and all pieces will be the same thickness for
an individual box. I hope the juice will be worth the squeeze. It will
be fun getting the fingers correct at the corners. Maybe start by
restricting the dimensions to a multiple of the finger size  plus.

Best wishes,

Ray

On 14/08/2020 02:56, William F. Adams via Discuss wrote:

I've done boxes like that already:
https://willadams.gitbook.io/design-into-3d/3d-project and https://cutrocket.com/p/5e8fd99cc1578/
and as noted, I've already managed to get the corners right for a fingerjoint box, which was the beginning of this conversation which apparently no one deemed worthy of actually looking at.
https://imgur.com/g9pQxS6

I want to do my CAD and CAM in OpenSCAD --- all I need to make it available to in an elegant (in terms of scientifically correct) and robust fashion which naïve users can make use of it is a way to get some numbers which I am using to call modules in OpenSCAD already into a text file without any extraneous stuff which has to be filtered out.
Yes, I could use some 3rd party tool --- then I get to tell folks:
 - install OpenSCAD and use it to set up your design - install a second tool, and run this other file as well, and tell it where you put your OpenSCAD file and what name you saved your Customizer preset under

It's an unnecessary complication --- if only OpenSCAD would be allowed to have a bit more control over writing out text files --- which would be useful for other purposes as well such as B.O.M.s
Yes, I've done something along those lines as documented in my article in:
http://www.tug.org/TUGboat/Contents/contents40-2.html
but it's a lot of extra baggage when a simple couple of preferences and one basic capability could sidestep it:
 - write out console with each run of openscad - when writing out console filter to only lines output by echo - use custom file extension ____ instead of .nc 
(though it would be nice if that last could be specified in the language/file as a command)
William

-----Original Message-----
From: Ray West raywest@raywest.com
To: William F. Adams via Discuss discuss@lists.openscad.org
Sent: Fri, Aug 14, 2020 6:47 am
Subject: Re: [OpenSCAD] !![SPAM]!! Re: Is there an OpenSCAD dev who wants a CNC machine? (was Re: Managed to model a finger joint box with relieved fingers --- now how to actually cut it? Allow OpenSCAD to write out files?)

Hi, Use scad for showing the picture, but imnsho, you would be better off generating the gcode separately. I've attached a screen shot of a simple box generator - no cad used whatsoever. The joints are not finger joints, but are a sort of stepped butt joint, modern glues are stronger than the wood.
I'm not sure if you need the ballnosed bit, or the tapered bit. Tool changing is a pain, unless you have some high end machine, or possibly designing a machine specifically for making finger joints. I've used  cutters similar to this, quite successfully for wood carving, which sort of combines a taper and a ballend. https://www.amazon.co.uk/SpeTool-Tapered-2-Flute-0-25mm-Coated/dp/B077883PDW/ref=sr_1_13?dchild=1&keywords=tapered+milling+cutter&qid=1597401368&sr=8-13 I'm guessing you have a sort of flatbed cnc routing table, and you do not really want to have to change tool bits, or manipulate the sheet which you are machining, and all pieces will be the same thickness for an individual box. I hope the juice will be worth the squeeze. It will be fun getting the fingers correct at the corners. Maybe start by restricting the dimensions to a multiple of the finger size  plus.
Best wishes,
Ray
On 14/08/2020 02:56, William F. Adams via Discuss wrote:

Ray West wrote:

Apparently.

It's the CAD tool which I prefer to use --- and I've modeled fingerjoints in it before:
https://community.carbide3d.com/t/cnc-finger-joint-box/8880

I am planning on using a 1/4" square endmill, a 1/16" ball-nosed tapered endmill, and a 1/4" radiusing endmill.

Tight enough for a void free joint.

I created a fixture for doing that:
https://cutrocket.com/p/5cb25f3380844/
and I've cut boxes thus:
https://cutrocket.com/p/5cb536396c281/
It's a tedious pain.

The refuge of the incompetent woodworker --- I'm trying to design a joinery system where joints have no visible voids --- hence the radius endmill which I intend to use to relieve the fingers to match the radius left by the 1/4" endmill. See the images at:
https://community.carbide3d.com/t/design-into-3d-boxes-magazine-storage/16238/54
and
https://community.carbide3d.com/t/cnc-finger-joint-box/8880/113
and
https://imgur.com/g9pQxS6
William

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I'm not sure exactly what question you are asking. Is it that you, for
some reason or other, you want openscad to be able to produce a text
file, possibly a list of coordinates, that you will manipulate somehow
to produce tool paths, or is it that you are trying to design a joinery
system? If you are trying to design a joinery system, then openscad is
not much use, other than perhaps as a check to see if the object looks
OK. For the sort of tooling/machinery you are most likely wanting to
use, even if openscad could write a text file, it would probably be more
awkward adjusting that file, than starting from scratch, and writing raw
gcode. As you say you have done similar before, you know how
straightforward that is, then there is little point in trying to push
openscad in a direction that apparently few are interested in.

Although openscad can produce the model, then you are stuck in getting
another view of it. If you create the model by some other method, most
likely you can more easily get more views of it (MVC paradigm). In other
words, generate a list of coordinates, then you can display them on a
screen (openscad/whatever) and generate offsets for Gcodes for machining
in whatever way you wish.

Have you actually made a sketch of how a couple of the fingers, say,
actually mesh together, when prepared by what ever router bits you can use?

Best wishes,

Ray

If this stuff was easy, everybody would be doing it...

On 14/08/2020 15:41, William F. Adams via Discuss wrote:

-o file.echo only captures the echos. Then all you need to do is remove the
ECHO: " " around it. An option to remove those would be handy.

On Fri, 14 Aug 2020 at 17:20, Jordan Brown openscad@jordan.maileater.net
wrote:

Jordan Brown wrote:

which is exactly why I'm trying to make this as straight-forward as possible.
Ray West wrote:

It would help if you'd look at the posts and images I've referenced.

Having designed a joinery system, I want to write out G-Code so that the parts can be cut out, since I haven't found a CAM program which will cut out the joinery designs I have created:
https://old.reddit.com/r/openscad/comments/i2do7a/managed_to_model_a_finger_joint_box_with_relieved/

I beg to differ. I find it very useful for the design --- please see the image:
https://imgur.com/g9pQxS6

I've posted pseudo code for getting the G-Code out of the radiuscut module which I wrote.

Argumentum ad populum

In my design work I always design from the manufacturing view, then rotate as needed.

Or, I could continue to just rotate in OpenSCAD

The way that I wish to generate them is to write them out of OpenSCAD.

Yes, see the links in my previous message.

nop head wrote:

Thank you for pointing this out --- it's quite helpful to me.

Agreed, as would exposing this with a menu option or preference.
William

Hi, William,

On 14/08/2020 19:10, William F. Adams via Discuss wrote:

Please give a link to where you have sketched the shape of the fingers,
and how they mesh, being capable of being produced by standard router
bits, perpendicular to the surface of the wood. i.e. in the sort of
machine that i thought you were intending to use - a flat bed cnc
router. I am not talking about your openscad drawing showing a few sides
that seem to be able to interlock, but where you have actually looked at
the final detailed shape of the individual fingers, and how you will
machine them. Afaik, this is not possible on a flat bed router, unless
you mess around standing them on edge, in which case it then becomes a
trivial problem (other than the work holding), or you're happy to use
gap filling glue.

You say you have designed a joinery system, well if it involves a four
or five axis bed/spindle, you will be in with a chance, but if only
three, then no chance, unless you go for two or more operations. I
suppose a cnc version of the edge milling box joint jigs may do, but
that is not a challenge. There is probably a reason why there is no cam
programs that will do what you want, after all, finger joints are pretty
popular, but already covered by various mechanical jigs. There are,
however, laser cutting cnc systems for finger joints, if you want to see
burn marks on the edges.

If you were to standardise on the minimum gap between the fingers, then
a design for a small mortiser would be interesting, and you'd get square
corners.

Best wishes,

Ray

Ray West asked:

Please see: https://community.carbide3d.com/t/cnc-finger-joint-box/8880/113?u=willadams and the posts above/below that.
You can see the details of the radiusing tool definition at: https://community.carbide3d.com/t/design-into-3d-boxes-magazine-storage/16238/54?u=willadams
I've also done a diagonal relief using a V endmill which worked surprisingly well:
https://community.carbide3d.com/t/design-into-3d-boxes-magazine-storage/16238/16?u=willadams

I've done them standing on edge. It's a tedious pain.

Yes, to two or more operations if you consider a tool change an operation, but only one setup.

Agreed, been there done that.

I've used generators intended for lasers as a starting point for some projects, but no interest in a laser --- agree that the burn marks look ghastly.

Not sure what you mean by that.
William

I have a CNC router with a tool changer operated by compressed air but I
have never got around to setting up the tool changer. It would be ideal for
that sort of job but would require accurate tool Z height calibration but I
have solved that problem before.
https://hydraraptor.blogspot.com/2007/05/how-long-is-your-tool.html

I have also never used it with wood but someday I will get around to it.

On Fri, 14 Aug 2020 at 21:38, William F. Adams via Discuss <
discuss@lists.openscad.org> wrote:

Thanks, William. I now see we are both right. Your quadrant table is the
fourth axis, in effect. Seems you've had a few arguments elsewhere, too.

A mortiser tool bit is basically a square tube, with sharp edge at the
bottom, and a drill running through the centre. The drill clears the
majority of the chips, leaving a thin ridge and corners for the tube to
shave off. It basically drills square holes in wood. If you rigged up a
similar unit, but with a cnc controlled x/y table to move the wood
around, then it could profile nice square notches. It would most likely
need more pressure than is capable to be exerted by the z axis drive of
the usual cnc routers, however, but there are ways around that.

If you knew someone who could harden and temper tool steel (It is quite
easy), then drill a  hole lengthwise through a steel bar, and
countersink the end (It'll give a sharp edge), then use an ordinary
auger bit in the centrer. You will need to cut away part of the side of
the bar, to let the chips escape. Or you can buy them ready made, of course.

If you limit the size of material you want to process, then you can
build a sturdy gantry type flat bed cnc router, with a beefier z drive
stepper and ball screw. A sharp bit, say 0.25 inch square will not take
much force to push it through most woods. It will not be particularly
fast, especially if you are doing all the cutting with the mortise bit,
but there should be little further processing required.

A bonus would be that you could use openscad to design the machine.

Best wishes,

Ray

On 14/08/2020 21:37, William F. Adams via Discuss wrote:

Hi William,

for the purpose of testing that the gcode generated is the gcode you can
use, it is simple to open it in any text editor, e.g. notepad, and do
search and replace a few times.

so search for 'echo' and replace with 'space', then same for double
quotes and commas. Finally search for spaces repeatedly replacing two
spaces with one,  this results in

 G0 X 0 Y 0 Z 8
 G1 Z -3.175 F 150
 G1 X 0 Y 4.20625 F 600
 G0 Z 8
 G0 X 9.5875 Y 0 Z 8
 G1 Z -3.175 F 150
 G1 X 9.5875 Y 4.20625 F 600

which is valid gcode, at least for my machines. That will allow you to
break out of the theory, and you can attempt to machine the pieces, and
see if they fit together as expected.

On 15/08/2020 05:16, William F. Adams via Discuss wrote:

Jordan Brown wrote:

I posted my source code at:
https://community.carbide3d.com/uploads/short-url/36SA8hMSvesRwUOKFocbbdxQmrl.zip
in the message: https://community.carbide3d.com/t/cnc-finger-joint-box/8880/126
and I've attached the current copy to this message.
Current settings are:

This is just a proof of concept so far, but I think it shows progress.
Just to review --- which CAM options have you looked at or considered? Thus far I've tried or worked with:
 - export STL --- process in a 3D CAM tool such as MeshCAM or pyCAM - export DXF or SVG --- process using a tool such as MakerCAM or Carbide Create
the other thing I've considered is:
 - opening the .scad file in FreeCAD and using its CAM workbench
Curious if there are any other options to try.
William

On 8/15/2020 5:20 AM, William F. Adams via Discuss wrote:

Remember that the people doing the work are volunteers, working in their
spare time on things that interest them.

It does seem pretty simple.  I'd offer to do it myself, but ... I got
OpenSCAD to build successfully in December, and since then I've found
the time to spend maybe two or three hours on the features that I want.

On 8/15/2020 5:20 AM, William F. Adams via Discuss wrote:

and Jordan Brown responded:

I would appreciate that.

Understood, hence my mention of a machine.
I'm hoping to shake some funds loose for Bounty Source --- an estimate on what should be offered?
William

OpenSCAD mailing list
Discuss@lists.openscad.org
http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org

On 8/15/2020 5:59 PM, William F. Adams wrote:

Interesting.  So pretty much you have two programs interlaced - once
that models a 3D object, and one that emits a toolpath, and they don't
really have much to do with each other except for sharing some dimensions.

The shape of your fingercuts is a cool workaround for the round shape of
the tool.

This is what I was looking for.

Last time I looked - don't remember exactly when, but a long time ago -
pyCAM seemed to be abandonware.  Looks like it may have been revived.

I don't remember whether I tried MeshCAM.  The fact that it's $250 was a
big stumbling block.  I'm spoiled by the mostly-free world of 3D
printing.  I think the only paid slicer in common usage is Simplify3D,
and it's only $149.

I looked at HeeksCAD and played with it a bit.  I seem to remember it
crashing a lot.

I looked at Fusion 360.  I don't remember whether it would import STL,
but it was very slow and I think I had a hard time understanding how to
use it.

Only marginally interested.  I want to model in 3D, not 2D with a fixed
depth for each shape.  (Maybe that's an unrealistic thing to want.)

The toolchain should be able to do something useful with a half-sphere:

intersection() {
    sphere(20);
    translate([-100,-100,0]) cube([200,200,200]);
}

And maybe that demonstrates my naïvety; tool head geometry might
preclude doing that because unless the bit is more than 20mm long the
tool head might hit the sphere getting to the edges.

Tools like Carbide Create are commonly called 2.5D, but if I understand
them correctly I think that I'd only give them 2.2D.  The device is
fundamentally limited in that it can only cut down (and so there cannot
be any overhangs of any kind), but it's perfectly capable of cutting
slopes.  Carbide Create and the ilk basically have you draw out
something in 2D and then specify a depth for each shape; they don't seem
to have any notion of slope.

Maybe I should get over it, treat the CNC as a 2D device - basically, a
cutter - with very limited 3D capabilities, rather than wanting it to be
the subtractive equivalent of a 3D printer.

Wouldn't this require a post OpenSCAD package that operates on .STL files to drive a milling machine, somewhat of the complexity of a slicer eg Cura for 3D printers?

Otherwise if you are working from pure logical shape identities, why use OpenSCAD in the first place?  It almost immediately makes extracting coordinates of shapes impossible or very convoluted.

It seems the answer to this is more than adding a filter to an output debugging stream into a new file format. Especially if a more generalised milling capability than the example given is required. If people designed their models in STL with the same caution as they do for 3D printing (eg resolution, overhangs, speeds, temperatures, etc etc) then it should possible to program a post STL processor that could prepare GCODE files for CAM that can work.

Personally I would find this a very attractive proposition, and useful to extend my (basic) OpenSCAD skills into this area. Cura began with just one line of code at sometime. But it certainly has grown full of useful features.
Cheers, RobW

On 16 August 2020 10:48:35 am AEST, Jordan Brown openscad@jordan.maileater.net wrote:

$&#@*(.  I hate mailing lists that set Reply-To to the list.  I meant
that to be a private message; that's why I hit "Reply" instead of "Reply
All".

On 8/15/2020 6:36 PM, William F. Adams via Discuss wrote:

I have a machine.  Just no time.  I should make some time for some of
this stuff; quarantine has freed up a bunch.

SainSmart 3018-PRO
https://www.sainsmart.com/collections/genmitsu-cnc/products/sainsmart-genmitsu-cnc-router-3018-pro-diy-kit

It was $200 on Woot.  That was within my "try it for fun" budget.  I
just wish it had limit switches.

Not a clue.  For me, personally, unless it was a ridiculously large
amount it wouldn't be a factor.  My day job pays enough to keep me in
toys.  Spare-time projects are for fun.  Offering me $50 or $100
wouldn't get my attention at all, and I don't think you want to offer $1000.

Jordan Brown wrote:

I'd describe it rather as a program which shows cutting out parts which has options to show said parts in various positions and to write out the G-Code (and some extra stuff which needs to be deleted).

Thanks! I've been working on this for a while now.
<big snip>

I think that's a fine thing to want --- there's no reason it couldn't be done using the technique I'm showing you'd just have to model the movement of the tool in 3 dimensions --- hopefully I'll learn enough math to make that happen presently.

intersection() {
sphere(20);
translate([-100,-100,0]) cube([200,200,200]);
}

It should be possible to do a ball-nosed endmill traveling over the surface of the hemisphere to shape it, then have a square endmill do a waterline path around the lower perimeter of it to cut that out.

That's 2.5D described as a limitation over full 3D.

Mostly. One can do V carving and textures --- I even did a joinery design abusing the Advanced V carving feature in Carbide Create.

There's always directly programming in G-Code --- with tools such as G-Sharp it might be workable:
https://github.com/NRSoft/GSharp
and there are more listed at: https://wiki.shapeoko.com/index.php/Programming

And Rob Ward wrote:

No, please see my code from my previous messages --- basically rather than modeling the shape, one models the stock and carves away from it using tool-shaped geometry and one captures the tool movement as G-Code.

I'm not, and I'm using OpenSCAD because it has a neat front-end in 
https://www.blockscad3d.com/
and I've pretty much managed to solve extracting the coordinates.
<snip description of something more complex than what I envision>
I will note that if one modeled a tool such as:
https://www.amazon.com/gp/product/B07XG6MTMH
or a ball cutter on a narrow shaft one could do undercuts.

Thanks! --- I'd be curious what you think of my code or my discussion of this at: https://community.carbide3d.com/t/cnc-finger-joint-box/8880/126
I'll take Jordan's hemisphere description and see if I can make that into a test cut file to cut tomorrow.
I also need to make some test cuts for kerf bending plywood --- since I don't want to go through the tedium of faking it out in Carbide Create directly coding this in OpenSCAD is attractive.
William

On 8/15/2020 7:30 PM, William F. Adams via Discuss wrote:

Generating the gcode in the general case is roughly equivalent to the
problem of generating gcode for a 3D printer - what a slicer does. 
There's an awful lot of calculation there.

I was thinking of the fact that the tool head - the thing that holds the
bit - is quite a bit larger than the bit itself, and on a near-vertical
surface with a bit that's shorter than the object being carved there's a
risk that the head will hit the piece.

Another way to look at it is that you're specifying the tool path, and
building a parallel OpenSCAD model of the tool path.

That's an interesting way to look at it - totally upside-down from how I
normally think about modeling.  Normally I think about the shape of the
object and the toolpath is largely the slicer's problem.

The fact that tool head shape matters is part of what makes my head hurt
when I think about general CNC.