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I'm creating simple Bezier line drawings in Designer and exporting them as SVG files. When I import them into Carbide Create, a CAM app for running a CNC machine, the scaling is too small, generally by a factor of about 5.6. I can't just scale up for two reasons. The lines get choppy and the scale factor is not always exactly the same. I've tried a number of parameter changes to no avail.

I have tried this process with iDraw and Inkscape, both export with proper scaling. When I import a Designer created SVG into either Inkscape or iDraw, I also must rescale the image although not necessarily with the same factor as Carbide Create. So, I suspect this is more an issue of how Designer is handling the SVGs.

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Hi bpedit,

I will pass this on to development to see what they say, but in all honesty I tried exporting a 10mm circle from Inkscape, Illustrator and Designer and all three files were opening as different sizes in each app, as well as Fusion 360 and Carbide Create. The Designer one does seem significantly larger in a couple of the imports, which I wonder is down to the 300dpi the document was created at. This is what I found (unfortunately I don't have access to a copy of iDraw to test with).

ExportSizes.png.8a0212797fd49bae9ded3c56582784eb.png

10mmCircleInkscape.svg

10mmCircleIllustrator.svg

10mmCircleDesigner.svg

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Hey Sean, thanks for running this;

Indeed, your 10mm opens about 9mm in Carbide Create (CC). This is much different than my experience. I have done several manipulations like greatly enlarging the document and object size but still see the huge size reduction. In fact, I've just made my own 10mm circle which measures 1.79 mm in CC. (There it is again, the 5.6X factor.) 

An apparently knowledgeable source on the Carbide 3D forum states that the DPI should have nothing to do with this. This makes sense considering SVGs are vectors. So I'm wondering what gets you closer to 1:1 I'm working in mm, sounds like you are too. But even if I can replicate your results, it's not good enough for my use where inlays must match pockets and engraving must fit precisly on the inlay. I.e., multiple toolpaths executed from multiple SVGs at multiple times needing to coincide.

My workflow right now is to use Designer to create the art then copy the image and paste it into Graphic (iDraw). Then I use Graphic to create the SVG which sizes perfectly in CC. One other advantage of Graphic over Designer is that Graphic allows creation of SVGs from a layer or selected objects. Designer seems to export everything including hidden layers meaning I have to save a copy for each layer I want to export and delete the remaining layers from that copy. More files, more confusion, especially if I want to modify.

Here's my 10 mm  circle from AD:

10mmCircle_2.svg

PS: Strange that AD opens its own creation at a different size!

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14 hours ago, bpedit said:

Hey Sean, thanks for running this;

Indeed, your 10mm opens about 9mm in Carbide Create (CC). This is much different than my experience. I have done several manipulations like greatly enlarging the document and object size but still see the huge size reduction. In fact, I've just made my own 10mm circle which measures 1.79 mm in CC. (There it is again, the 5.6X factor.) 

~~~~~

My workflow right now is to use Designer to create the art then copy the image and paste it into Graphic (iDraw). Then I use Graphic to create the SVG which sizes perfectly in CC. One other advantage of Graphic over Designer is that Graphic allows creation of SVGs from a layer or selected objects. Designer seems to export everything including hidden layers meaning I have to save a copy for each layer I want to export and delete the remaining layers from that copy. More files, more confusion, especially if I want to modify.

It sounds as though you didn't realise it was possible to limit the export to selected objects. If you select which objects you want to export and change 'Area: Whole Document' to 'Area: Selection without Background' option you can limit your export to the selected objects. This was what I was doing when exporting out the 10mm Circle, which in turn I found that exporting with Area: Whole Document and Area: Selection without Background gave quite drastically different sizes when importing into Carbide Create, which also seems wrong! I'll update development with that :)

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7 hours ago, Sean P said:

It sounds as though you didn't realise it was possible to limit the export to selected objects. If you select which objects you want to export and change 'Area: Whole Document' to 'Area: Selection without Background' option you can limit your export to the selected objects.

Bingo! Thanks, I didn't read the fine print. But I still get the wrong scaling in Carbide Create. My 50.0 mm test frame imports at 8.954 mm, still the same ~5.6 scale-up needed as in my other imports.

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On 9/19/2018 at 10:20 AM, bpedit said:

Bingo! Thanks, I didn't read the fine print. But I still get the wrong scaling in Carbide Create. My 50.0 mm test frame imports at 8.954 mm, still the same ~5.6 scale-up needed as in my other imports.

I discovered on August 23 within (see topic below) that setting my Affinity Designer document to "96 DPI" allows me import the exported SVG into Fusion 360 at the correct size. Perhaps Carbide has something similar? I was seeing pretty similar results to yours when I didn't have the AD document's DPI set to 96.

 

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On 9/25/2019 at 12:39 PM, DorffMeister said:

I discovered on August 23 within (see topic below) that setting my Affinity Designer document to "96 DPI" allows me import the exported SVG into Fusion 360 at the correct size. Perhaps Carbide has something similar? I was seeing pretty similar results to yours when I didn't have the AD document's DPI set to 96.

Thanks, I gave it a try. But I seem to have the opposite result with Carbide Create (CC). I changed the dpi [from 300] to 96, as you suggested, but that made the CC import too small by a factor of 24 instead of the 5.6 I was getting. Since it seems to be an inverse relationship, I tried raising the dpi to 1000. This produced a CC import that was almost half-size. Seemingly on the right track, I tried a dpi of 2000 but it made no difference from 1000. I guess Designer has a limit. Very curious why Designer would relate vector scale to dpi, of what use is dictating a size in that case.

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If you look at the SVG file itself, look at the "svg" tag (close to the top) for the "width" and "height" attributes.

Are they present, and if so, are they specified in pixels, or in some real-world unit such as inches?

 

If they are in pixels, then different programs might be interpreting those pixel counts according to their own dpi settings or some assumed default, which could be different from program to program and thus give you varied scaling across the programs.

If they are not present, then there is nothing for the interpreting program to go on to determine the size of the image other than the viewBox, which has no units attached to it - a viewBox of "0 0 10 10" could be interpreted as being 11 pixels wide, 11 points wide, or 11 feet wide - there is nothing to give the image a sense of scale, so a program trying to read the file has to guess at how big to make it.  Again, you could get wildly varied scaling across different programs.

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The CSS standard for SVG is 96 DPI. If you set your AD Doc to 96 DPI and create your 10mm circle and export it at 96 DPI (irrespective of the fact that SVG is resolution independent) then when imported into Carbide Create the import is the correct size which suggests CC is honouring the 96 DPI standard.

If creating the 10mm circle in a document larger than 10mm x 10mm then as Sean mentioned, select the circle and change 'Area: Whole Document' to 'Area: Selection without Background' prior to exporting.


Affinity Photo 1.7.3, Affinity Designer 1.7.3, Affinity Publisher 1.7.3

MacBook Pro 16GB, macOS Mojave 10.14.6

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Figured I'd chime in here and on some other threads I've been to recently, hopefully if anyone is searching for what I was, they will end up here.  I was having issues taking my vector designs from Affinity Designer in SVG into a program called Sheetcam for operating my cnc plasma.  I could not get the scale to remain where I wanted it.  As much as Inkscape got me started in vector design, I didn't want to have to run my designs through just to make a DXF (which still didn't import perfectly anyway) so I tried using pixels, mm, changing the DPI, but it wasn't working.  In the end, I just did some math to see what the factor was that Sheetcam was changing my designs by.  Obviously I had to make sure the units were the same in each program on export and import as well. My 10 inch square imported at roughly 10.6667.  So I just divided what it should be, by what it was. and came up with .9375.  Sheet cam gives you an option at every import to select the scale to import in.  So Instead of picking 1:1 I make it 1:.9375 and it's perfect.  

I'd like to understand why this works the way it does, whether DPI affects this or not, but I'm content to be able to use my drawings in inches and with the scaling trick.

 

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Hi Brownfox,

As far as I can tell, AD is exporting SVG's at the correct size, I believe the 'issue' is with Sheetcam having read a few comments in their forum. I'm not a Sheetcam user but exporting a 96 dpi 10 x 10 inch object as an SVG from AD is giving me a 10 x 10 inch file which imports into other software at the correct size.

Have you checked the exported size of your AD square, is it showing at the correct size prior to importing into Sheetcam or is it showing as 10.6667 inches when exported?


Affinity Photo 1.7.3, Affinity Designer 1.7.3, Affinity Publisher 1.7.3

MacBook Pro 16GB, macOS Mojave 10.14.6

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Sorry, I should have specified.  It was this thread that showed what different sizes other CNC programs imported at that made me do the math.  Yes, Affinity does export at the correct size, its the CAD programs interpretation that is askew.  A few searches made me think it was an Affinity issue, but it is in fact, not.

 

Like @bpedit wrote above, his CNC program made an update so it assumes a 96 DPI scale.  I haven't really dug into sheetcam as much as I should have yet, but I'm guessing it's the same issue.  Most peoples solution is to use Inkscape to export as DXF, but I managed to do that wrong too somehow.  lol.  Besides, I love using affinity.

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