First off, this is my first post on this forum. Thanks in advance for any input anyone gives me.

Let me tell my story. I am very new to inkscape. But I have been prepping a file for laser cutting. I emailed the fabricator the file in the link below, and I was surprised to find that I got a letter back. They said the following:

There appear to be unintended cut lines on your file. There is a series of lines that cut out the top right quarter of your design (and through some of your other designs in the process). If this is intentional, please let us know and we will proceed with the file "as is"

If you look at the file, there are 0 lines described like that. None whatsoever. Regardless, I cut out a few things. tried again. sent it off.

That same "L" cut still exists in this file. If it helps to identify it at all, there are actually quite a few stacked copies of it. And they are likely in multiple layers on your original as they're attached to different pieces in this file.

tried a couple other long shot changes. sent it off.

This file still contains (at least 52 repeats of) the lines that cut through the top right corner of your file. Please let us know if you would like to proceed as is or make revisions.

Here is the thing. The file looks perfectly fine. There is only one layer. It visibly has no lines at all. However, if they are saying its a cut, then it has to be either RGB blue, red or green.

So how do I fish out these lines, or even start to find them? I am stuck.

A link to the file I was working on is here.
https://www.dropbox.com/s/8bxlggixg62ap4o/catan_sent.svg I would attach it but its too big.

Hi.

Are the blue lines should be the cut-lines?
If so, did you try to send them a blank file with only those to check?
Maybe they are converting it to plt/dxf before, which causes the trouble.

Opened in inkscape, it seems that the blue lines have different attributes.
Changed them to one.

Some random thoughts/Qs:

Have you tried sending a "plain" svg or PDF?

Are you engraving and cutting this image?

Some laser cutters use line-width to identify a cut (e.g. hairline), so if there are line widths that fall into that range within the engraving content, a separate cut file that is registered may need to be sent.

Any additional info regarding the jobber's specifications for submittal and what equipment/software they use may be helpful.

I just got everyone's messages today and I have to say thanks guys. All your input is greatly appreciated. Especially since I am 100% lost with this.

To answer some questions, here are the guidelines for laser cutting/etching:

Use vector lines under 0.3pt (0.00416in or 0.10566mm) for line cutting and line etching. In CorelDRAW use hairline. An easy number to remember is 0.1mm.

Line Cut
Blue stroke < 0.3pt (RGB value 0,0,255) cut.
Line Etch
Magenta stroke < 0.3pt (RGB value 255,0,255) light etch (for light marking).
Green stroke < 0.3pt (RGB value 0,255,0) medium etch.
Red stroke < 0.3pt (RGB value 255,0,0) heavy etch (for transparent acrylic). This weakens the acrylic as it cuts deep into it.
Raster Etch
10% Black fill or stroke > 0.3pt (RGB value 230,230,230) light etch.
50% Black fill or stroke > 0.3pt (RGB value 128,128,128) medium etch.
100% Black fill or stroke > 0.3pt (RGB value 0,0,0) heavy etch.

The file format that they prefer is a pdf file.

The patterns in black are shades of black are the be etched, all other parts are cut. So by process of elimination, I know several things. These 52 layers of cut are RGB blue, since that is the color of cuts.

Hi,

With laser printing take care about Ctrl + A selection.
Ex : you have different shapes and you want all its stroke being engraved. You select all shaped with Ctrl + A and set stroke color + witdth corresponding to your engrave needs. Then you print it.
Problem : you will see lot of lines coming from 1 corner, it corresponds to shapes positioning vector (from origin to your shape).
It is not visible in Inkscape even if you do a Ctl - A, it's normal as it is your obect position. But as you modify all strokes, its width has been modified and must be engraved. So you will engrave all your shapes strokes + its positioning vectors.

Lahorde

Hi,

Take care about positioning vector. May be lines your are seeing are your shapes positioning vector.
Normally it has a stroke width of 0. But when you modify stroke width for your engraving you can can modify it accidentally. And you get positioning vector with a stroke width. So these vectors will be engraved...

Lahorde

A few more thoughts:

Seems the jobber is setting the machine for grayscale.

Apples and oranges may be mixing here...? Color mapping seems exclusive of grayscale mapping, so if machine is set to grayscale (all the etching art is grayscale), all lines <0.3pt will be cut. Perhaps provide a file with the gray and black changed to red and green, so only blue is cut.


Possible issue: some artwork is white paths over black, perhaps boolean those elements to black-only paths.

Hmm. Wow thank you guys. I didn't even know about these positioning vectors. That control-A thing sounds like something I would do.

Okay, I have an update as well for you guys to input into those giant brains of yours. I asked them to send me a screen shot of what they were seeing on their end.

A quick note:
the alterations to the top right hex were intentional. I was trying trial-and-error to find the hex that was causing the erros. However, other than those changes, all the other changes are complete surprises to me.



Assuming it is a positioning vector, How do I remove it? How do I got about fixing all this?

That looks like what I see when opening Inkscape SVG files in Corel.

The original file looks fine to me in Adobe Reader when output as a PDF. I'd ask if that is suitable for them and specify to have them print from Reader and only the blue lines cut.

Hello

Lahorde wrote:Hi,

Take care about positioning vector. May be lines your are seeing are your shapes positioning vector.
Normally it has a stroke width of 0. But when you modify stroke width for your engraving you can can modify it accidentally. And you get positioning vector with a stroke width. So these vectors will be engraved...

Lahorde

Now that We see the image, I think that Lahorde is refering to those blue lines in the center of your drawing?. I think the simple solution is tell the fabricator to erase those blue lines, and continue with the job.
For future works may be other options:
- Save as PDF
- Save as Plain SVG
- Save as Optimized SVG
- Export to DXF (But you must convert ALL the drawings to paths, even the text, and even the hatches).

Maybe is a bug en CorelDraw and not in Inkscape?. I still don't see the reason for the appearing of those blue line when importing to Corel

Hey,

Just a more precise explanation for positioning vector, if you reproduce following steps :
-draw a star and a rectangle, remove its filling, just keep its stroke : you want to cut it with laser
-modify stroke according to your laser software cut values : in my case it must be a red line of about 0.001px
Print it : in laser preview you see your shapes

Now do following steps :
-draw a star and a rectangle, remove its filling, just keep its stroke : you want to cut it with laser
-modify RECTANGLE stroke according to your laser software cut values : in my case it must be a red line of about 0.001px
-modify STAR stroke : a black 0.001px stroke
Print it : you see this image


A strange line appears.
If I modify stroke color from black to red, problematic line disappears.

In fact when you modify black stroke it also modify a shape position dependent vector. And after, it is expected to be cut.
To solve it, just modify stroke color : IT MUSTN'T BE BLACK!

I'm using Trotec JobControl. To be sure it is a reproductible issue and an Inkscape problem, a good test would be to reproduce given steps on another laser cut software;

But for your case, it doesn't seem to be same issue. This blue line with a different width seems strange.

Lahorde

Hello Lahorde:
Now I seet that yours it's a diferent issue. When i put that stroke width in inkscape, the stroke doesn't show on the screen. I could break my head for a thousand years to figure why. Could you try to export your drawing in other format? PDF, EPS,DXF? Or use an SVG optimized or a Plain SVG. If you choose optimized read carefully the options. The simpler the SVG, more probabilities that the bug doesn't appear,... right?.

The most simple SVG:



The only conclusion is that even svg format varies between Inkscape, Corel, or Adobe Illustrator ! It shouldn't be like that.

Hello Hulf,

For very small strokes width not displayed with Inkscape I posted before : http://www.inkscapeforum.com/viewtopic.php?f=5&t=16570
I would prefer either modify a preference or change some source code in order to NEVER hide some strokes even if it is very small. But may be a reason I missed exist for this hide behavior, is it same behavior in Illustrator?

You are true, my issue must be a different one, in fact I think I have two issues :
1- strange lines displayed in my laser cut software : Inkscape isn't guilty for position lines. It seems to be a problem from laser cut software. I compared two SVG : one correctly displayed (red stroke) and other not correctly displayed (black stroke) in laser cut software. Only color differs in svg xml comparison => laser cut software must introduce these strange lines reflecting shape position. It's not Inkscape that introduces extra data when modifying black stroke!

2 - svg with small strokes width export. With simple svg you gave, have you managed to export it in a format where rectangle is displayed? If no, is it normal behavior? Does same issue exist in other svg editors?

Lahorde

Just SVG... Seeing in diferent web browsers...
In Firefox, when the width is 0.001 doesn't show, even when is zoomed
in Chrome, it shows, better when zoomed.

But the idea is that you test it with your laser printer's software. I understand that your software accepts svg as input file?

Just a thought with so thin lines: inkscape has more inaccuracy than that.
About 0,003-0,008 pixels, if a boolean operation is done.
When displayed on screen in true size, you have to bear with anti-aliasing too.
Below 3,5 pixels, you cannot get a consistent non-blurred part displayed along the path if it goes in a random direction.

And, is that a good idea, to think in pixels for printing vectors?
Isn't using mm or inch units more handy?