Hi all, new to this forum, hoping to find some help with an issue I'm having.

I'm using (trying) to use Inkscape to convert a png image into GCode for engraving a door sign I want to make with my GNC-3018 cnc.

Currently, I import the image into Inkscape, do "Path->Trace Bitmap..." to convert it into a path, then I use "Extensions->Gcodetools->Orientation Points..." to set the reference frame and "Extensions->Gcodetools->Tools library..." to set the tool parameters.

The I generate the Gcode with "Extensions->Gcodetools->Path to Gcode..."

It all works great, except that it puts the tool cutouts *exactly* in the middle of the bitmap edges, which screws up my cutout because it "cuts outside the lines" if you know what I mean?

The shapes are cut too big and "merge" into each other :(

I've being trying to find *some* way to make the path cutouts be *INSIDE* the traced bitmap shapes, but to no avail.

I thought perhaps "Path->Inset" or "Path->Dynamic Offset..." might do it, but they are AWFUL :(

Instead of just moving the path inside the shapes, they use some kind of shrinking algorithm to shrink the shapes themselves AND THEN STILL PUT THE PATHS DIRECTLY ON THE LINES INSTEAD OF INSIDE.

PLEASE - *somebody* tell me what I need to do to make the Gcode tool cut "inside the lines" of my traced bitmap shapes!

Thanks!

You didn't wrote what kind of tracing you're using. If the centre line tracing wasn't used Inkscape creates color filled shapes means a path running as an outline around a line/stroke. View->Display mode-> Outline can help to check what exactly you have on the canvas.

You didn't wrote what kind of tracing you're using.

Just going to quote what I already wrote: "Currently, I import the image into Inkscape, do "Path->Trace Bitmap..." to convert it into a path".

Other than that, I have no idea what you are talking about, there was no other option or parameter related to "tracing" during the whole process.

"Centerline tracing" is the *opposite* of what I want though, that's what it's doing now. I want it to do "inset tracing" and only trace *inside* an object.

I tried "View->Display mode->Outline" after tracing the imported bitmap and prior to doing any of the GCode actions (orientation, tool, path), but sadly this forum wont let me post any images (I tried the "Upload File" button in the attachment clip at the bottom, but selecting a file and clicking "ok" on the upload dialog literally does nothing) so that's not very helpful,

Anyways it just shows me the traced outlines of the edges of the shapes in my bitmap though, which I already understood.

The tracing seems fine, my issue is how to get the generated GCode to cut *inside* the lines and not *on top* of them. I'm using a 2mm routing bit, cutting on the lines destroys the shapes, keeping the routing bit *inside* the shapes would not.

I made some nice pics in GIMP showing what I mean, but again, this forum will not let me upload pics :( I've tried to reproduce them in ASCII art (because why not?) so I hope this conveys what I am trying to say:

Let's say this is my traced lines:

 /----------\
 |            |
 |            |
 |            |
 |            |
 |            |
 |            |
 \----------/
    

Path to Gcode generates this (*** is cutout path):

***********
*/----------\*
*|********|*
*|*         *|*
*|*         *|*
*|*         *|*
*|*         *|*
*|********|*
*\----------/*
***********   

I *want* it to generate this:

Path to Gcode generates this (*** is cutout path):

 /----------\
 |********|
 |********|
 |**      **|
 |**      **|
 |********|
 |********|
 \----------/

Thanks!

Use the paperclip icon to upload images.

BTW when in GIMP you can color select and convert any selection into a vector Path which you can then export to SVG which can be edited in Inkscape. As I said the default bitmap trace function of Inkscape will generate color filled shapes and a machine that will follow these paths will draw 2 lines side-by-side when small strokes are traced. You can tear apart inner and outer strokes by going Path->Break apart if this helps.

Use the paperclip icon to upload images

 Is there another way? That's what I was trying.

I click the paper clip in bottom left, click the big blue "Upload File" button, select my image, click "OK" and nothing happens.

As I said the default bitmap trace function of Inkscape will generate color filled shapes and a machine that will follow these paths will draw 2 lines side-by-side when small strokes are traced. You can tear apart inner and outer strokes by going Path->Break apart if this helps.    

I don't actually understand any of that, I am rather new to Inkscape, I don't know the jargon :(

From whatever sense I can make about what you are saying - I don't think you understand what I am trying to accomplish.

As I said before, the "Trace Bitmap" part of the process doesn't seem to be the issue, and I understand what it's doing. For instance, let's say my image is a big black block letter "O":

########

##           ##

##           ##

##           ##

##           ##

########

The "Trace Bitmap" function traces out the edges of the shape with, as you say, 2 lines, one outside and the other inside, like so:

----------------

|  -----------  |

|  |          |  |

|  |          |  |

|  |          |  |

|  |          |  |

|  -----------  |

----------------

I get what it's doing up to here, I have no problem with it, this is fine. The issue is somewhere in the Gcodetools process. It keeps plotting the cuts centered on the traced lines.

e.g. if the lines are the trace and the stars where the generated  code tells the tool to cut, it does this:

*|*

With the tool cutting directly on top of the line, instead of what I want: on the side towards the inside of the shape:

|**

Perhaps this will help, I have made a public Facebook post with the images. Hopefully you are able to see them and this will make sense:

https://www.facebook.com/permalink.php?story_fbid=pfbid02RyaowKyh1jmD2EQgVb5ikjKzqN6NzQxRArRCHyspTwfkQcvD1wgRN8XgvMVNeEral&id=61550581885233

Hey, just giving this a bump.

Still haven't been able to solve this - anyone have any ideas?

thx!

P.S. for the mods/maintainers: forum upload is still broken...