Hello

In a first .SVG file, I have a drawing with several layers. One of them - the so called the agregation layer - contains the copy of several other layer. In this agregation layer, the stroke style of some lines is drawned with dashes, width of 0,150 mm (to see them clearly) and pattern offset of 10.00 . I saved this layer in a .pdf document (File > Save as ... > .pdf).
Now I make Inkscape close the .pdf document and open my .svg file again.
No problem; these dashed lines do appear as dashed lines in the .svg and in the .pdf documents that I can display in the canvas of Inkscape application.

With this agregation layer displayed in the canvas, I select all the lines (CTRL A) and in Fill and Stroke > Stroke style, I replace 'Width 100.000' and '%' by 'mm' and '0,025' , because that is what our lasercutter needs. It results that we do not see the lines in the canvas anymore, although they are there, just too thin, I expect. Also the dashed lines must be there.

Then I save the .svg drawing file under another name : ... Aggreg LaserCutter 0,025.svg . Inkscape diplays now this ... Aggreg LaserCutter 0,025.svg file content, as expected. And there is still nothing we can see in the canvas for the same reason : too thin lines.
Then I save this ... Aggreg LaserCutter 0,025.svg file content in a eponimous .pdf file that I intend to pass to the lasercutter later. Inkscape displays its content which again seems to be empty.
Bad surprise when I open it in Adobe Reader : the dashed lines are not dashed anymore (are continuous) !
For verification purpose, I select all the lines of the ...pdf document that is open in Inkscape, and I change their width to 0.150 again. Bad surprise confirmed : the dashing is gone.
I then re-open the original ... Aggreg LaserCutter 0,025.svg file. There too the dashing is gone ! When ? Why ? Does the save as ...pdf alterate the content in some way ?
How to get saved ...svg and ...pdf files with the lines keeped dashed ?

Have a nice day. Many thanks in advance.

PS: Incidentally, please recall me the right command to shift a rectangle so that its center corresponds to the center of the A4 page in the canvas.

I always suggest to "Save copy" when making a PDF cut file for a laser (Epilog).

Dashes on a stroke will not make many small cuts, the path geometry is still continuous:

An object can be aligned to center using the Align and Distribute dialog (Ctrl+Shift+A).

Have a nice day.

TD

Do I understand correctly that you're using the offset dashed lines as a visual indication of where the paths are, because you can't see the actual paths?  And the problem is that somewhere along the way, the dashed lines are not displayed and you have a solid line instead?

I just made a local test, and the PDF file does show the dashes.  What version are you using?  I tested in 0.92.3.

It sounds like the first time you saved as PDF, the dashes were preserved, right?

I have an idea.  I think you said that after you save as PDF, you open the PDF again in Inkscape (which converts it back to SVG, by the way) (and then when you save as PDF, it's converted again). What if instead, you save 2 parallel files, an SVG and a PDF.  Always open the SVG file, if you need to edit and re-save another PDF file.  This avoids one file conversion.  And always when you save a PDF file, be sure to save an SVG file first.  Always make edits in a file that was originally SVG.  And always save a special SVG file (when you save a PDF), in case you need to make edits again.

That's hard to explain, so if you don't understand, just tell me and I'll try again.  I suspect the problem is happening because of multiple file conversions.  And when you have special styles in file, like dashed lines, or maybe filters (or many other things), file conversions can be deadly.  So having an SVG file for editing avoids one file conversion, compared to editing the PDF.

If you open the PDF file with the missing dashes, are you able to re-set the dashed line?  Maybe that would be the fastest way to a solution?

Hi Chavadam,
It is like Tyler says. A dotted line in Inkscape is really a normal line. The style on top of that line is dotted.

You can change the line to a really dotted line with menu > extensions > modify path > convert to dashes.
Then you have a real dotted line in the svg file.

The example below show the first line with the style dotted. It has only 2 nodes.
The second line is converted with convert to dashes. Every dash begins and ends with a node. Between the dashes there is no path.
That is what your lasercutter needs.

Both Tyler and Brynn had good suggestions to always keep the original svg. Make a copy of it.
Then try this in the copy, so you always have your original design safe somewhere else.
You can export from this file to pdf. But do not import that pdf back again and work in it.

Hello

Thank you, Tyler Durden, Brynn and Kirstie for your answers.

Tyler,
With your movie, I understand that you show how to draw a rectangle with dashed strokes (0.025 mm thick). You then move a corner to show that the dashed lines are still there. I explained that the issue is that when the drawing has been modified and then saved (in .svg and in .pdf) and re-open again, the dashed lines are not dashed anymore, but continuous. How to keep the strokes dashed after save and re-open ? Thanks for your effort.

Brynn,
No, it is not that I am using the offset dashed lines as a visual indication of where the paths are, because I can't see the actual paths.
The issue is that when one saves the *.svg (or *.pdf) BEFORE changing the stroke thickness (from e.g. 0,150 mm  to 0,025 mm), the saved files, after close and re-open, show dashed lines still dashed (as it ought to be). But when one saves the *.svg (or *.pdf) AFTER reducing the stroke thickness (and changing the file name), the saved files show continuous lines (even they are difficult to see, because too thin lines), as well in *.svg as in *.pdf .
See the four little files enclosed. So, I was saving two parallel files, an SVG and a PDF, as you suggest, I think.
So yes, after modification of the thickness (or other change) and closing the .svg and .pdf file, the dashing of the strokes are disappeared and I have a solid line instead.
I'm using Inkscape version 0.92 . I don't care of 'Pattern offset'.
I'll operate your suggested manoeuvre completely and attentively soon. Many thanks.

Kirstie,
I did not know the difference between a dashed line and its style, that you explained here. I'll try it this evening. Many thanks in advance.

Kind regards.

Chavadam

But when one saves the *.svg (or *.pdf) AFTER reducing the stroke thickness (and changing the file name), the saved files show continuous lines (even they are difficult to see, because too thin lines), as well in *.svg as in *.pdf .

Oh, I understand better now.  Now I can test....  Hhmm, no I cannot reproduce that....well, not exactly, but sort of.

When you open the PDF in Inkscape, the line should be opening in a group, one way or another (whether it's a group by itself or within a larger group).  If I change the stroke width without ungrouping, the path becomes a solid line at that point.  Not after save or re-open, but right there on the canvas.  To keep the dashes, I have to either ungroup it, or select with Node tool.

I'm not sure if what I found would be considered a bug or not.  But could it be what is happening in your experience?

Oh, I just noticed something else.  When you see the solid line, are you looking at an open SVG or PDF file?  Or are you looking at a preview in a file manager?  Or the preview in the Open PDF dialog?  I think you have been clear that you are actually opening the files.  But I mention it just in case (since we've seen other people accepting the preview as the actual state of the file).  The preview, no matter where you see it, will always show the solid line, because it actually is a solid path, with a customized display.  The previews are not sophisticated enough to see the customized style.

Bonjour ou bonsoir.
and thanks a lot, Brynn and Kirstie.

Brynn,

 "If I change the stroke width without ungrouping, the path becomes a solid line at that point.  Not after save or re-open, but right there on the canvas."
Strange : As from the file '1 Dashed 0.150.svg', ...
1) the (unique) line cannot be ungrouped, as it is not in a group.
2) the path becomes a solid line after save and re-open; not right there on the canvas.
I was never looking at a preview in a file manager, nor alike.
Live can be so hard, sometimes ...
Many thanks for all you appreciated efforts.

Kirstie,
I used menu > extensions > modify path > convert to dashes as you advised... successfully !
See the new four attached files '3 Dashed 0.150.svg', '3 Dashed 0.150.pdf',  '4 Dashed 0.150 ConvertedToDashes.svg' and  '4 Dashed 0.150 ConvertedToDashes.svg'
Thanks a lot.

I apply now this 'convert to dashes' to my little project and I'll test it out on the laser cutter in two hours. I'll send you then some pictures ...

I'm really grateful.
Best Regards

@Chavadam , please note that the dash length is proportional to the stroke thickness. You may look closely and find the dashes are in the files 0.025 (svg & pdf).

See zoomed view in both programs:

Chavadam

2) the path becomes a solid line after save and re-open; not right there on the canvas

I've tried this with your file, many times, and I can't reproduce it.

I hope Kirstie's solution will work for you.

Hi Chavadam,
This extension is especially made for this kind of thing and lasercutting, I thought. I so hope the test will be succesful.

Remember to always work on a copy when you convert your line to real dashes with this extension.
The final dashes have many nodes and are very difficult to manipulate. So it is best to only convert to dashes at the final stage of your design.

You can always go back to your original file if you have to change things.