Yes, yes, I was just making fun of the charming way you guys spell things! 
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You mean the proper way, before you deliberately changed the spellings?
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Guilty.
BTW, I was carpooling a group of 3rd graders and overheard, “I can speak British! I want a tomahto with my potahto!” Then another said, “Stop it and start speaking English.”
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We can’t spell things they way we spell them. To give us credit for deliberately doin it is hilaireus 
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By the way, the suggestion to try to render all at one is ok rather than the two operations for exporting the svg. It’s easy enough to bring the SVG into Inkscape, break apart the file, and select the bounding cut rectangle and change the color, because you have to scale it anyway. As long as you are bringing it into Inkscape, might as well do this.
But if you brought the resulting exported SVG straight from OpenSCAD, you would all be marked with one operation and isn’t scaled right.
But this is a great file! Thanks again.
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You do? You shouldn’t need to… when it’s exported from OpenSCAD it’s all to scale in millimeters. Inkscape imports it correctly in mm, at the right length… how are you having to adjust it’s size? I’m actively trying to avoid needing any manual scaling, because that’s a step I’d rather remove.
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Inkscape likes to default to pixels instead of mm when importing. It’s gotten me a few times. I just re-import and pay attention to my settings. Then I’m good.
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Huh. I never had that problem. There’s a difference between the Display Units (what’s shown in the Inkscape edit ruler) and the Page Units (what it uses for printing)… but I always found the Page Units to reflect the correct document unit of measure. It’s annoying that Display Units changes to px, but I kind of accept that.
Just change Display Units. Don’t change Page Units is my advice.
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First I took some time to work through Inkscape tutorials. Then, once I proved to myself that it worked (OpenSCAD -> Inkscape) I haven’t been back to Inkscape much. I just remember the import messing with scale and a dialog where I had to change it from pixels to mm to fix it. I thought maybe that was the issue.
Once I’m done with the libraries I want to write in OpenSCAD my plan is to go back to Inkscape and learn to add the decorative flourishes well and quickly. The timeline for that was last summer. Glowforge aren’t the only ones behind schedule.
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Same. If Inkscape had some form of scripted language then I might be more inclined, but I’m more comfortable with symmetry through rigid constraints… and programming the design lets me do that.
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The whole scaling issue is a bit of a challenge for me. I can get it taken care of. Then there was the recent upgrade to Inkscape that changed scaling from old documents. They all seemed to work, but sometimes when I was mixing files and importing it got scrambled.
In any case, the file is usable. I’ll test again a direct import into the Glowforge from the OpenSCAD SVG export and see what happens. Last time, it was a only about three inches instead of twelve.
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It’s not impossible. But I do think a ruler is a poor choice of initial prints until accuracy is completely… accurate.
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It is a good test of the machine though. Wooden rulers will change length with humidity. Plastic rulers will change length with temperature, steel much less so. In this case I would bet on the steel ruler being the most accurate and the Glowforge being off. Some machines seem more accurate than others.
I have no idea how Glowforge can get positioning precision to 0.001” (0.025mm) over 20+" with belts and open loop stepper drive but precision only means it is repeatable. It doesn’t mean it is accurate and I suspect what they really mean is the resolution is 25um.
Are we expecting dimensional accuracy to improve at this late stage?
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I sure am.
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People make the assumption that all metal rulers are printed accurately, but there are no guarantees. I personally own a 12" and 39" metal ruler, and they’re off as much as 0.1 mm per 12 inches from each other. Even digital calipers will be off by some amount.
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Indeed, unless you have the need and are willing to pay the big bucks accuracy will always be something you can see with the naked eye. I look for precision in a tool more than accuracy.
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I need accuracy when making things if they have to mate with something else. If the precision is good but accuracy poor I would expect a way of calibrating the axes with a scale factor. If not I would have to scale my designs.
Not only linear dimensions but also right angles need to be right angles. I.e. X & Y need to be orthogonal to high accuracy as well.
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In my limited experience with cnc routers and now with the Glowforge, accuracy today is so much better today than it was 10 years ago for a particular price point. The thing is, it will vary with materials and all kinds of other factors. If you have to have sub-mm accuracy across the size of the bed then a laser or cnc router simply is not for you. You need a cnc mill or an EDM machine.
Personally, I am fine with a .25mm error across the bed size as wood and plastics will grow and shrink with temp and humidity anyway.
Good news here, this is simple trig. if your linear dimensions are precise then you will have correct angles. I’ve not seen any angle error large enough to measure.
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Theoretically but not it practice. If the X axis is not exactly perpendicular to the Y axis you can get linear X and Y movements accurate but right angles off. With the type of Y axis used it is quite hard to keep the gantry perpendicular in my experience.
It would be interesting to see a founders set square.
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