SVG world unit handling (or DXF export)

[bskrt]

TL;DR 1) add dxf support (in- & export) 2) Change SVG exports to world/document units instead of pixels.

I recently bought Designer to escape Adobe hell, but I am running into a rather large annoyance:

We do a lot of lasercutting/CNC routing at our studio which needs DXF files to work (feature request 1, please add DXF support).
I understand this isn't implemented in Designer atm and this wouldn't have to be a deal breaker if SVG export would work properly as I could always use or write an SVG to DXF converter.

The problem with current state of SVG:

Every SVG is converted to pixel units on export.
What that means is that if I design a document in mm, it will be converted to pixels using the DPI setting in the export menu. I've figured out that 96dpi does seem to "work" to get the SVG in "correct" dimensions. Though, due to the fact that mm units are converted to pixels using DPI and are then reconverted to mm when opened up in other software packages, there are rounding errors.

Example, 100mm converted to pixels at 96dpi

(100mm*96dpi)/25.4mm = 377.952755906px

Now, due to the nature of the codebase, that resulting float value is probably being rounded to a number of decimals (all SVG height & width values seem to be limited to 2 decimals), so when we try to convert that "rounded value" back to mm, my initial 100mm isn't quite that anymore.

(377.95px/96dpi)*25.4mm = 99.999270833mm

One might argue this is not an actual issue for the final result of the work you're doing, as lasercutting and routing wood have a larger error margin than that anyway, but it is for communications sake. When I tell my CNC partner something is 100mm, it needs to be 100mm, not 99.999.

Besides that, this just feels like a bad implementation of SVG anyhow. Why would you even convert units.

The only workaround I have found is drawing everything up in pixels and manually changing the svg code to use mm. eg.:

<svg width="100%" height="100%" viewBox="0 0 1280 800" ... >

to

<svg width="1280mm" height="800mm" viewBox="0 0 1280 800" ... >

This way all the values of the paths are interpreted correctly as being in mm instead of pixels, but this just feels like an ugly patch on something that should not be that hard to fix and implement.

Please fix this. Thanks.

[Patrick Connor]

@bskrt

Hi, Welcome to the Serif Affinity forums  

Thanks for your feedback, on SVG. The best thread to follow for DXF import/export is here

 

[ChrisBr]

On 10/15/2019 at 7:27 PM, Patrick Connor said:

@bskrt

Hi, Welcome to the Serif Affinity forums  

Thanks for your feedback, on SVG. The best thread to follow for DXF import/export is here

 

The post you linked to does not appear to be there anymore.

I use AD for for vinyl cutting and also rely on accurate dimensions. Currently, I cannot achieve this without using other third-party software.

[Patrick Connor]

@ChrisBr

Welcome to the Serif Affinity forums  

The tagging in these forms would imply one of these  many other threads may be useful, or indeed one of these 500+ threads. Although a popular request it is not something we have had time to implement yet, sorry

It is odd that other one has gone awol (perhaps it got too heated as they sometimes do).