Is there a programmer here who could make a minor change in OpenSCAD?

#1

Trying to get a design cut, but am stymied on the CAM end of things — if I could just write out a text file from OpenSCAD I’d have it I think.

All I need is for any text which is added to the Console via Echo() to be exported via a menu entry (yes, I know I could filter it out w/ a utility or fancy search/replace but I want this to be something that a naïve user could do). Asked for it in an Issue:

but got shot down.

There’s on-going discussion in a different issue as well as the mailing list — I think it’d be accepted if it came in over the transom as a code patch, at least I hope it would.

Simplest expression:

Just adding a parallel output where if one called echo() only that text was written out to a second file (with a user configurable file extension) would work — no added menu entry, just a pair of configuration options:

[ ] write out echo text in separate file
[ ] custom file extension, use ____ instead of .txt

that’s all that would be necessary to allow folks to experiment with directly creating G-Code for CAM. (EDIT: and doing lots of other things such as compiling a B.O.M.)

If anyone is able to look into this I’d be grateful.

#2

Hey Will,

I’ve used OpenSCAD a fair amount. I had a look at the code and could add a writeln(“filename.nc”,{}) type of function to their grammar that would do the sort of thing you are after.

If this was a personal build for you on a single platform, then that’s straightforward. But if you wanted it to be generic and available to others then the OpenSCAD team would need to accept a pull request, and they seem to be reluctant about the overall concept.

So the code changes are easy, but making, updating and distributing builds is more complicated… and, well, tedious :slight_smile:

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#3

Thanks! I really want this in the available builds and agree the politics of it are the problem.

Turns out that the code is pretty much already in place, see:

All that is necessary would be:

  • a preference for writing out the file

  • a way to run OpenSCAD with the equivalent of the command-line option:

    -o file.echo

which only captures the echoes — ideally after stripping out the extraneous text, if not, a way to run sed or some other suitable tool.

  • a preference (or command) in the language for specifying the file extension

I’m hoping that not asking for a new menu command, and burying this in the preferences will make this palatable.

#4

If you’re happy with that sort of solution, why not run the following:

$ cat file.echo | grep -e "^ECHO:" | cut -f2 -d'"' > myfile.nc

This will work on macOS or WSL on windows… put it into a script that takes the filename parameter and substitutes it, and you are done, no?

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#5

Because I don’t want the headache of telling everyone who ever uses one of my projects to do that.

#6

The suggestion is that people who run this run:

$ willadams.sh mybox.scad toolpath.nc

and end up with the toolpath.nc file ready to go.

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#7

Thanks. I don’t want to have to distribute the script — the thing is, being able to write out the echoed text would also be useful folks using OpenSCAD more generally — generating a B.O.M. comes to mind.

If it won’t just work directly, I guess I’ll either switch to AngelCAD or FreeCAD.

#8

Fair enough.

You could write out the commands in the first ECHO statement instead. Then to generate the NC file the person would just need to remove the first ECHO: and then run the output to generate the NC file.

For example, write this:

ECHO: (grep -e "^ECHO:" | cut -f2 -d'"') << 'ECHO: EOF'
ECHO: "G0 X0 Y0 Z8"
ECHO: "G1 Z-3.175 F150"
ECHO: "G1 X0 Y4.20625 F600"
ECHO: "G0 Z8"
ECHO: "G0 X6.89856 Y0 Z8"
ECHO: "G1 Z-3.175 F150"
ECHO: "G1 X6.89856 Y4.20625 F600"
ECHO: "G0 Z8"
ECHO: EOF

Then all you need to do is remove the first ECHO: (ie: 5 characters) and then: bash file.echo

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#9

Yeah, I miss the concept of Oberon and everything being a script one could run.

#10

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