[NTG-context] Creating SVG: using MetaFun, exporting proper units, conversion to DXF

Mojca Miklavec mojca.miklavec.lists at gmail.com
Wed Jun 29 22:49:30 CEST 2016


On 29 June 2016 at 14:12, Hans Hagen wrote:
> On 6/29/2016 12:31 PM, Mojca Miklavec wrote:
>>
>> Hi,
>>
>> I want to play with CNC and don't yet have any experience with CAD
>> software (nor the licence for the expensive ones) other than perhaps
>> some Blender, so I decided to try to use the super ugly route with
>>     metapost -> svg -> dxf -> g-code
>> for the first time.
>>
>> I have a few questions.
>>
>> (1) I love Hans' shortcuts in metafun, but I seem to remember that things
>> like
>>     input metafun;
>> or perhaps
>>     input mp-tool;
>> used to work, so that I don't have to remember to use
>>     mpost -mem=metafun my-drawings.mp
>> when compiling the graphics.
>>
>> Did the method with "input" ever work (or is it supposed to work)? Now
>> I'm getting a bunch of weird errors.
>> I would love to specify everything in the source file and then just
>> call mpost. If that doesn't work, that's fine, I can still add
>> "-mem=metafun", but ...
>
>
> input metafun.mpiv ;

How should one properly compile that file then to get the SVG?

Using just "mpost something.mp" doesn't work that way.

>> (2) I guess that using "raw metapost" is the only sane way to generate
>> SVG. If I use metapost inside ConTeXt that's probably not going to
>> work, right?
>>
>> (3) Is there any way to convince the SVG output mode to generate something
>> like
>>     <svg ... width="100.0mm" height="100.0mm" ... >
>> rather than
>>     <svg ... width="283.46456692913387" height="283.46456692913387" ... >
>> because the program I use to convert SVG to DXF has troubles
>> interpreting "points" properly. I read somewhere that they assume 90
>> points per inch because that's Inkskape's default.
>
> why not just
>
> \startMPpage
>   whatever you want
> \stopMPpage
>
> and then use mudraw (mutools) to go from pdf to svg (that's what i do when i
> need svg)

Given that metapost supports SVG natively I imagined that it would
produce a simpler/cleaner output. Thanks a lot for the suggestion,
I'll test it.

It turned out that the (opensource) tools I used for converting SVG
into DXF gives very weird result, so I have to change the other parts
of the "toolchain" as well.

Nevertheless, the question about whether one could convince MP to
output true units in cm/mm/in.

Mojca


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