Inkscape scaling again

Use inches for the display units and for page size for a document and use the scaling dimensions in this screenshot and then load the gift card and see what it looks like.

Perhaps somewhere along the line it looks like your scale got set wonky for the default. Not sure that there is something odd with the Mac version or not that might have made this happen or an older svg from the pre 96DPI change in Inkscape that did something.

No change. And it looks like you have the exact same size I do. Measure the larger circle. I get 3.8mm/0.15". Also measure the blue inset box on the bottom. I get 68x44, which is not large enough for a gift card.

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I pulled down the gift card holder and indeed, it displays incorrectly. I note this is an SVG from AI - and I’ve seen posts on here before where AI does something funky with scaling. Looking at the source, I can’t see why, as it looks like plain SVG. The circles are defined as 7.2(x2) and 4.81(x4). There’s no “scaling” that I can see (and no dpi )

I created a file with two 7.2mm and four 4.81 circles and noted they are defined using drastically different code.

I’ve never seen this issue but I’m curious to understand so I might look into this more tomorrow.

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Here is what I have.

Paging @cynd11, paging @cynd11. Can you weigh in on this design and the scaling issues?

Right, and if you change to 72dpi, you get a reasonable size for the design.

Both of these files (with 72 and 96 dpi) show up the same size on the GFUI, probably because of the 12x20 artboard.

This comes back to my initial question: in this case, even though Inkscape says it is too small, it prints correctly. But if I tried to edit the initial file with actual measurements, it would come out incorrect by 72/96.

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Aaaak! Sorry I can’t help. I designed the gift card holder in Illustrator (version CS5 if that matters) on a 20” x 12” artboard. I used whatever scaling defaults existed for Illustrator at the time. If you tell me what specific info you need, I’ll pull it out for ya.

I’ve seen this before. My solution was always to cut and paste the design into a new document and then everything works.

The proper [easy] thing to do here is issue a bug report, the gf ui is misinterpreting inkscape-saved svgs that seem to be the correct dpi.

The proper [harder] thing to do here is get forensic and open the svg in a text editor, and dig through the metadata to try to find something that looks different from a native inkscape file.

If I weren’t in an airport security line as I type this I’d be all over it, because this has been annoying me for a long time. I mean yeah I can multitask but doing it right now is a lot even for me. :slight_smile:


@eflyguy you seem like you probably know your way around a diff, you want to take this on?

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I just tried that, and it did not work. Same result as opening the document directly, or importing it into the glowforge template. Now, if you are saying that the design really should be smaller than I expect, then everything is actually working as expected. But I was not wiling to assume that I was doing this correctly.

OK, so this implies that Inkscape and I are interpreting the SVGs correctly. Does the GFUI still scale any artboard that is 5:3 to fill the 12x20 space? If so, this is how the GFUI is getting it to look correct.

I don’t think this is a question for any specific design. I was really questioning my process. I do have some questions about how you used the veneer, but I’ll ask in the original thread.

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Here’s a screenshot of the dimensions of the largest rectangle (should be 4.503 inches) in Illustrator:

Thanks. That’s what I get if I tell Inkscape to use 72 dpi, instead of its default 96dpi. I now know how to scale this design if I need to edit it (for example if I have different magnets). But the larger question is how to recognize this issue in generic SVGs.

You’re kind of at the mercy of the author in that case, since DPI doesn’t get stored in the SVG. This is why I put a measurement square in my designs.

The method I gave you up above is the best one I’ve found. In ensures your material is going to fit together correctly.

Unless the author was just a sloppy designer, it works every time. (And to rule out sloppy designers, just check the dimensions of multiple slots.)

Thanks for going through all these steps with us again. It took me a while to understand what the deal is but it does seem that the GFUI is doing something wonky with the sizing for something like this.

@cynd11, what are the exact millimeter dimensions of the inner rectangle for the card and then all the holes in your design space?

I’ll print out this out too on mine and see what gives. Just needed references because all the dimensions are kind of swimming around here. I’m working on the CNC and two 3D printers and coordinate systems and measuring systems are somewhat illusory in my brain.

Large rectangle: 114.386mm x 71.882mm
Small rectangle: 91.008mm x 59.182mm
Chicago screw hole: 5.08mm x 5.08mm
Magnet pocket: 3.394mm x 3.394mm

I think when I get a chance I will go back and add a reference rectangle to all my uploaded designs. I confess that it never occurred to me that it would be needed.

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It’s just nice to see everyone assisting to identify and fix these problems. Thanks.

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I remember the gist is that if you design in Illustrator, export your file as a pdf - which will preserve the correct dimensions regardless of what you open it into, including Inkscape. That’s why @designvh619 ended up changing all his previously uploaded files to avoid sizing issues between users.

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If you’re talking about differences between the files, they are very similar in the headers, but use different syntax to generate the circles (for example).

I looked thru the header portions which have mostly identical parameters, nothing that would affect scaling. Then I spotted this, AI uses:


… but Inkscape uses:


I wonder if there’s something in those included files that makes a difference?

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We spent a lot of time in the early days staring at SVGs to try to understand what worked and what didn’t. The Glowforge software has heuristics and workarounds, some of which are triggered by fingerprinting the file to guess what broken software created it.

Illustrator, in “Save As… SVG” mode, uses “px” as the units, where 1 px = 1/72 in. This is only Illustrator’s opinion, not enshrined in any specification, and is therefore subject to interpretation. The only reason this works is that the Glowforge software sees the comment that says “Illustrator made this” and knows about this assumption, so it interprets the file accordingly. But as we see in this thread, trying to bring it into different software that has different interpretation of what a “px” is can be problematic.

I much prefer the cleaner SVG produced by Illustrator’s “Export”, which appears to be a completely independent implementation from Save As. It produces (as long as you uncheck “Responsive”) real-world units like “in”, which can’t be misinterpreted.

Unfortunately, “Export” SVG has been historically buggier and that’s why there’s a lot of superstition around only using Save As. I have only seen one of those bugs actually crop up on the forum, and it was in an older version, but it’s worth noting that if you use Export, you’re not following the instructions provided by Glowforge and in some sense forfeiting your chance to complain to support if it doesn’t work.

In the course of trying to understand these behaviors, I have read the entire SVG specification, and may have had a few mini-strokes as a consequence. It is an interesting piece of work, particularly the parts that talk about units and coordinate spaces.


Does the “Adobe Illustrator 15.0.2, SVG Export Plug-In” in the header of the original file indicate the “export” option?