There are a couple of things.

All the paths are drawn clockwise. If you run Union on each ring before executing Difference you will get a different result. Not necessrilt better!

If however you break apart the each ring and reverse the direction of one component path from each pair, and then combine, before running Difference you will I think get the result you are looking for.

-u

---- On Sun, 24 Apr 2016 14:19:27 +0000 Brynn <brynn@...3089...> wrote ----

Thanks C R.

That was the first thing I thought too, at first. The bottom object must
have a stroke. But as I said, they are both filled with no stroke.

Here's link to SVG file: http://inkscapecommunity.com/jd/imgs/diff-diff.svg
. It has the rings already duplicated. So to reproduce, select the top
green and top gold rings, and do Difference.

Thanks again :-)
brynn

___________________________________
From: C R
Sent: Saturday, April 23, 2016 12:05 PM
To: Inkscape User Community
Subject: Re: [Inkscape-user] Difference difference

Could not duplicate the error, however if you have a stroke applied to your
shapes that is the same colour as your fill, that may explain what we are
seeing here. :)

Boolean shape ops are done to fills only, and do not take into account line
thickness on the resulting paths (this is intentional).

-C

On Sat, Apr 23, 2016 at 6:21 PM, Brynn <brynn@...3089...> wrote:

Hi Friends,
It seems like I should know the answer to this. But I don't recall
hearing about it.
Starting with these 2 rings, which have fill and no stroke:
http://inkscapecommunity.com/jd/ss/diff1.png
I duplicate both, and then Difference. At 100% zoom they look ok.
But zoom in (in this case, all the way, for best view) and you can see that
the Difference wasn't correct. http://inkscapecommunity.com/jd/ss/diff2.png
It's not a huge amount, but I would expect there shouldn't be any
difference at all. This on Windows 7, 64-bit, sp1, Inkscape 0.91, 32-bit,
exe installer.
Is that a bug? Or is there some reason it's expected not to be
precise?

Thanks for your help :-)
brynn

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