# Import SVG - size problem?

I’m using the new inkscape and blender version. In inkscape, I create a rectangle with this sizes: 17m x 20m, no border. Then, I save it as a svg file. Next, I import it in blender: File > Import > SVG.

The problem here is the size of the object. X is 17 (This is correct) and Y is 19.996 (This is not correct). What I’m doing wrong.

0.4% off, this would be how you make science in real life i’d say. Calculations in Blender are done using so called floating point math and these numbers assume there is an error margin in calculations. Vertices are stored as 32bit floats.

Hi. This must be a bug. There is also a problem when I rotate the rectangle.

I posted a bug report. You can read it here:
https://developer.blender.org/T44996#314265

If you still do not believe it’s floating point conversions (and might be that Inkscape is to blame) - here’s a blend file to play with.
http://www.pasteall.org/pic/show.php?id=89251

This is what is stored in your SVG file concerning the rectangle’s size:

id=“rect3336”
width=“60236.219”
height=“70866.141”

Not 17 x 20 m or 17,000 x 20,000 mm, but all in SVG’s own arbitrary unit system, which to my knowledge is based on pixels (with 1 mm = 3.543307px).

Let’s do the math:
width = 60236.219 / 3.543307 = 17,000 mm (so far, so good),
height = 70866.141 / 3.543307 = 20,000.00028222223 mm (oops).

So, not even with SVG’s internal unit system you will get a mathematically “clean” result for the height. Now add the aforementioned imprecisions in floating point conversions on top of that and suddenly a deviation of 4 mm over a length of 20 m sounds not so bad.

Care to elaborate how this is a “problem” for your workflow?
Frankly, this example seems a bit contrived to me. Blender is not supposed to be a tool for any kind of high-precision modeling anyway. And for visualization purposes - well, who is ever going to spot a deviation so tiny?

This MIGHT help with adjustments after the import

(Edit mode)

(Blender does have a built in measurement tool as well)

https://www.blender.org/manual/grease_pencil/ruler_and_protractor.html

Haven’t used them enough to favor one over the other.