Making ScanNCut Canvas designs in Inkscape

Before you get carried away using your Brother ScanNCut machine to cut out objects you’ve carefully designed in Inkscape, do this simple test * :-

  1. Use Inkscape to create a simple one inch by one inch square. Save the file as an SVG.
  2. Create a new project in ScanNCut Canvas. Import the SVG file from step 1.
  3. Click on the newly imported rectangle, and read the width and height dimensions from the screen.

If Canvas says the rectangle is 1.0″ by 1.0″, congratulations, all is well.

If, as I suspect from the behaviour on my machine, Canvas says 0.937″, then you have a problem. Anything you design in Inkscape and convert with ScanNCut Canvas will be exactly (90/96) times smaller than it should be. (My carefully designed watercolour filofax-compatible pages won’t fit on the ring-binders.)

A Simple Work-Around

Scale the whole object up (by 96/90, or 1.066666), either in Inkscape or in Canvas. Every time. :(

So What Is Wrong?

The simple answer is that SVG is a unitless standard. There is no information in an Inkscape SVG file that says what any given unit of length represents.

Inkscape defaults to 90 internal units per inch. When you selected ‘inches’ as your measurement unit, and created a 1″ by 1″ square, Inkscape converted that into its own internal units, and made it 90 units by 90 units. You can see this by opening the SVG file in a plain text editor. The width and height values are clearly set to exactly 90.

Canvas (at least on my machine) defaults to 96 units per inch. So when Canvas reads in a SVG file with a rectangle that is 90 x 90 units, it thinks of it as being just under an inch each way, since an inch square to Canvas is 96 x 96.

I can’t yet see any way to tell Canvas what units per inch to work with. I can see how to tell Inkscape to use 96 units per inch, it just doesn’t seem to work! There are two files (‘units.txt’ and ‘units.xml’) in the Inkscape system that supposedly let you set your unit relationships. Sadly, at least on my version of Inkscape on Windows 7, both of those files seem to be ignored in favour of the default values of 90 units per inch.

So until a better version of Inkscape comes along, or Brother gives us an Inkscape-friendly import option, we’ll have to manually scale things up by 96/90 each time.

* If anyone needs more detailed instructions on how to do this, tell me in the comments and I’ll write a more complete tutorial on getting simple Inkscape designs to cut on your ScanNCut. Right now I’m concentrating on learning enough Inkscape to make things look pretty as well as the right size :)

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5 Responses to Making ScanNCut Canvas designs in Inkscape

  1. John Scibran says:

    Hi there, I just purchased the ScanNCut and have been exploring it and just downloaded Inkscape to help create designs. I poked around the program before trying your sizing suggestion. I found the global preferences icon on the main screen and found 2 items set at 90. The first was under Import/Export. As it’s first Item is a field called “Default Export Resolution” set to 90. I changed that to 96. Then under Bitmaps, there is an item “Resolution for Create Bitmap Copy” was also set to 90. I changed that to 96. I then created a 1″ square in Inkscape. Saved as .svg. I then Imported it into Canvas and it came out to 1″ square exactly. I am using Windows 7 and version 0.48 of Inkscape. You didn’t mention if you had changed any fields in the global preferences. If you did, then I guess your system isn’t working correctly. If you didn’t find these setting, it might work for you too.

    • Hi John,
      thanks for the response. You had my hopes raised for a moment there. Sadly, those fields you changed relate only to the export of SVG as bitmaps, so far as I can tell. Changing them (which I had done previously) made no difference to the dimensions Inkscape saved in its SVG file and which Canvas reads.
      I’ve just tried again. If it worked, I’d expect that when I specify a dimension of 1 inch for an object, then change the unit of measurement to px, I’d get whatever I’d set for the export dpi. But I don’t, I still get 90dpi.
      Could you tell me exactly what version of the Inkscape installer you used? Mine is Inkscape-0.48.4-64bit.exe I’m wondering if the compiler settings on the one I’m using just don’t work properly on 64 bit Windows 7.
      Ah well, hopefully this all means that most people won’t suffer from this problem at all.

  2. John Scibran says:

    That’s the same version that I have. Another suggestion, did you try to uninstall the program and then reinstall it? Sometimes a fresh install fixes things.

    • Yep, tried that. Tried the 32-bit version. All failed in the same way. But, I now have a solution! I’ll write a post about that now, rather than hiding it down here in the comments. Thanks for the motivation to solve this!

  3. Pingback: Setting dpi in Inkscape for ScanNCut Canvas | Brazen Artifice

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