Hello all:

Probably a fairly easy question but one that eludes me in my learning thus far on using INKSCAPE.

I am collaborating with a gent with a CNC router who has kindly offered to create a master of my Burning Man medallion design. He's asks me to save each new version in DXF file that his CNC software uses.

Apparently, INKSCAPE is saving my designs in DXF in metric format providing MMs measures. This gent asks that I change that to INCHES.

How do I accomplish this, anyone?

Thanks, Jim
E: biller9506 at mypacks dotnet

Welcome varocketry!
I don't have any experience with DXF, so I just tried saving a test file. Unfortunately, I don't have the proper software to open it, so I couldn't investigate the units issue. But when I clicked Save, I got a small Desktop Cutting Plotter dialog. It has 2 tabs. The first tab is Options, and has only one setting, a checkbox, "Enable ROBO-Master output". The second tab is Help, and displays 5 list items, which seem to me describe what about DXF that Inkscape supports. One of those items is : "assume DXF drawing is in mm" (And another is "assume SVG is in px, at 90 dpi").

So all I can suggest is saving a couple of test files, one with the box checked and another with it not checked. I have no idea if this might work. But you could give it a try while waiting for others to chime in

Bump.

varocketry wrote:Bump.

Brynn has taken the time to investigate your issue and provide what appears to be some pretty sound suggestions. Perhaps instead of bumping the post you can respond with evidence that you've tried the suggestions and detail the outcome.

Microugly:

I didn't read an answer to my question in Brynn's response. Do you?
I've seen the same conversion assumptions listed in the DXF save but it doesn't answer my question.

I've since found the Document Properties function where INCHES can be selected for the drawing vice MM. But when I saved again, the Assumptions popup under Help still stated the converter 'assumes' the drawing is in MM. I don't know if that will cause a conversion problem that will only be apparent when the machinist opens the file.

Was your response meant to be helpful?

Hhm, I guess I wasn't clear enough in my original reply.
My thought (and I have no idea whether it's valid; just guessing based on evidence at hand, along with my own particular skill level) was that checking the box enables this ROBO-Master, which would apply the assumptions in the Help tab. My reasoning is that maybe if the box is NOT checked, then mm would not be applied. (or vice versa) Of course I have no idea what might be applied instead of mm, because I'm just making a somewhat educated guess.

And I think microUgly's point is that others might be waiting for you to reply whether you had tried it each way (with and without checking the box), and what your results were, before joining the discussion. Since now you have said that checking or unchecking the box apparently makes no difference, I hope that someone else will know more about it than I do (which is next to nothing, after all), and will be able to give some more helpful advice.

I might also mention that this is the first time I have seen this question asked in these forums, ever, which leads me to think it may be a matter of days before someone who happens to know the answer, happens to visit the forum. There have been frequent postings about various aspects of DXF, but I'm sorry to say, not this specifically (that I remember).

My next suggestion was going to be changing the default units in Document Properties, but sounds like you already tried it, with no luck

I do have a couple more thoughts though. Since DXF is a Desktop Cutting Plotter, I wonder if your file uses a grid? I've noticed that even if I change the default units to something besides px, grids are still displayed in px, apparently by default. So IF there's a grid involved, you might try changing it to mm units, and probably cross your fingers while you do it

And the other thought -- even if I change the default units to something besides px, I notice that the page size units do not change. So for example, in Document Properties > Page tab > Format > Page Size, some page sizes are given in mm, some are given in inches, and a couple in px. But if I change the Default Units, those page sizes remain the same. I don't really know, across the process of designing an image (which creates the XML/SVG code) then converting to DXF, where or when the units are created, changed or inherited. Maybe it comes from a grid (as I wondered above) or maybe it comes from the original page size/template, or maybe it's sealed in fate at the SVG to DXF conversion, and can't be changed at all with Inkscape??

Clearly I'm just "thinking on my feet" here, and chances are I have not solved your problem. It may be that this is the only way Inkscape can perform the SVG to DXF conversion? Beyond these thoughts, I can only suggest looking at other software which is capable of this conversion. Maybe search the internet? I'm really sorry I couldn't be more helpful, but I really do think there's a good chance your question will be answered. It just might not be right away, unfortunately.

Oh! PS - When you tried changing the Default Units in Doc Prop, did you also change the Custom Size Units? Even though you might not be using a custom size, the dimensions in the Custom Size setting change depending on which selection you make from the templates above. And there IS a Units setting that is separate from the Defualt Units! (which I find surprising that so MANY various parts of Inkscape have their own Units setting, and that the Default Unit setting doesn't cover everything)

Fingers crossed!
All best

Thanks, folks.

My only use of BUMP was to keep it near the top as I and most visitors rarely look beyond the top page for current discussions.
If it buries several pages deep , it'll never be seen or answered.

I have a follow-up but different question based on latest trials so I'll start a new topic and leave this one for the Metric-Inches conversion.
Jim

Thanks, brynns, microugly.
I was only using BUMP to keep the message near the top of new discussions, as we know most people don't look deep through the pages when looking for new discussion topics. If it dropped several pages back, there'd be little chance of ever getting an answer.

I have a new question but it is different so I'll post to a new topic.

varocketry wrote:Apparently, INKSCAPE is saving my designs in DXF in metric format providing MMs measures. This gent asks that I change that to INCHES.

How do I accomplish this, anyone?

The units conversion from px (units used in the SVG source file) to mm (units of the DXF file) is a hard-coded scaling factor in the python script that is used for the DXF (R13) export.

You can either file a feature request in the bug tracker or find someone with python coding skills who can help you to either change the scale used for the DXF export or implement a new option (drop down list) to allow the user to select the unit for the output file.

Hello,

The file you export is either bigger or smaller. Either way the error is a factor 25.4 (inch to mm conversion)
Hence can you not simply try the following...
TOO BIG : Scale down your drawing by 25.4
TOO SMALL : Scale up your Drawing by 25.4 (prob. this is what you need).

This is a bypass, but will hopefully work
shrikanth

I was glad to find this thread...I'm facing the exact some issue. Thanks to everyone posting here!

Our hackerspace ( http://www.collexion.net ) is building a computer cart for our CNC router.

The plans for the cart ( http://www.evilmadscientist.com/2012/cnc-workstation/ ) were created in Inkscape. I installed Inkscape so I could save the .svg file as a .dxf. (first time user) When I imported it into CamBam, I found the file was in mm, not the inches my American brain is stuck with.

I tried changing to inches in Inksape under document properties. This did not change the dxf to inches.

After finding this thread, I tried all four combinations of ROBO-Master and LWPOLYLINE on and off, without success.

In the end, I went in a direction similar to shrikanth's suggestion. Under Object -> Transform -> Scale, I scaled X and Y to 3.937% (which is 1/25.4). Then when I saved the .dxf file, my parts were expressed numerically in inches, although still labelled as mm.

Pulling that into CamBam, I changed the units from mm to inches (which does NOT scale the numbers...weird) and now my 4 foot part is 47.998 inches. While the extra decimal places are annoying, 0.002" is a far closer tolerance than I can actually cut, so I'm happy.

........

Epilogue

Then I looked at doing the scaling in CamBam instead of in Inkscape. Turns out under CamBam's Transform -> Resize, there are buttons dedicated to converting between mm and inches. In hindsight, I think that is a cleaner approach. It leaves the original drawing unmolested in Inkscape, and is a sliver easier, as you don't have to derive the ratio each time and type it in correctly.

Thought I'd share what I'd found. If there is a better way to export an inch .dxf file in Inkscape, I'd still love to hear it!

Cheers,
-dave

v1nce wrote:

Off topic:

just drop this obsolete unit nobody cares of...

brynn wrote:

Off topic:

v1nce, you should be able to delete your own messages. Look for a small X button, right beside the EDIT button

v1nce wrote:

Off topic:

brynn wrote:v1nce, you should be able to delete your own messages. Look for a small X button, right beside the EDIT button

I don't get it.

v1nce, when you said "just drop this obsolete unit nodbady cares of...." I thought you had posted a message, changed your mind, but couldn't figure out how to delete it. Now I realize that you must have meant unit as a unit of measure, i.e. inches or mm.

I apologize for misunderstanding.

Edit
And PS -- if you're referring to inches as obsolete, I think you're premature. Ha, ha -- I remember in 6th grade (12 to 13 years old) we were told that we better start learning metric measurements, because the whole rest of the world uses metric except for the US. But here I am in 'upper middle age' to 'early old age' with the US still using predominately....well, not metric (I'm not even sure what the units we use are called, lol).

brynn wrote:

v1nce wrote:

Off topic:

just drop this obsolete unit nobody cares of...

brynn wrote:

Off topic:

v1nce, you should be able to delete your own messages. Look for a small X button, right beside the EDIT button

v1nce wrote:

Off topic:

brynn wrote:v1nce, you should be able to delete your own messages. Look for a small X button, right beside the EDIT button

I don't get it.

v1nce, when you said "just drop this obsolete unit nodbady cares of...." I thought you had posted a message, changed your mind, but couldn't figure out how to delete it. Now I realize that you must have meant unit as a unit of measure, i.e. inches or mm.

I apologize for misunderstanding.

Edit
And PS -- if you're referring to inches as obsolete, I think you're premature. Ha, ha -- I remember in 6th grade (12 to 13 years old) we were told that we better start learning metric measurements, because the whole rest of the world uses metric except for the US. But here I am in 'upper middle age' to 'early old age' with the US still using predominately....well, not metric (I'm not even sure what the units we use are called, lol).

Not only because the rest of the world use them but because there are far more logical (there are direct relation between weights, lengths and volumes)

Some of my friends went to the US for school and they told me they were faster than locals when doing Maths.
They convert everything into sane units, make the computation and convert back into those strange oddities.

(In France we still use some units that are outside of the SI but that's for things that really matter (wine) )


To be a little more constructive about the topic I think OP will find usefull information @ http://www.cocreateusers.org/forum/showthread.php?t=4761

I've figured out a workaround with this issue. My drawings are in inches and converting them by saving as DXF puts them into mm. The drawings in DXF are 25.4 times my original, which is how I know this is in millimeters.

I went ahead changed the unit of measure in Inkscape to mm, then I scaled the drawing down to size. For example, the original was 65 inches, the scaled down drawing became 65 millimeters. Then save as DXF. When I opened this in QCad (the free trial I really like) the drawing opened as 65 inches. This worked very well and was much simpler than trying to load extensions, etc.

Welcome to InkscapeForum!

I don't have any use for DXF currently, but this does sound like a handy technique. Although I'm not quite clear about it, that's probably because I don't use DXF.

However, I was just making a test DXF file, to try and help in another topic. And I do see inches in the Desktop Cutting Plotter dialog! (in the Base Unit dropdown menu) Perhaps this is new in version 0.48.4?