seam allowance tool adding unexpected lines

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AmosG
Posts: 6
Joined: Sun Sep 05, 2021 11:28 am

seam allowance tool adding unexpected lines

Post by AmosG »

Hi, I'm having a bit of an issue with the seam allowance tool, whereby after adding the seam allowance on some pieces and wanting to remove it on specific sides of the piece the tool will remove the desired seam allowance but it will also add a number of lines cutting across the pattern piece.
AmosG
Posts: 6
Joined: Sun Sep 05, 2021 11:28 am

Re: seam allowance tool adding unexpected lines

Post by AmosG »

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TiesOli
Site Admin
Posts: 160
Joined: Mon May 13, 2019 3:13 pm

Re: seam allowance tool adding unexpected lines

Post by TiesOli »

Uh, you have two polygons in this patternpiece, having made the dart inside a second one.
Normally you would have this dart only as marking inside the patternpiece. You certainly wouldn't want the dart to have seam allowances.

In Extract, when you turn on Auto Markings, it will automatically put such darts as markings into the patternpiece.
After that, seam allowance should work quite nicely. However, the "0.0" seam is a special thing and can have little strays at times, but never so severe. It is designed to work perfectly on fold, along straight lines, while it does get a little confused, when you use it along Bezier curves. But it tries its best. :)

I made a quick little video for you, again starting with your original project (sorry about that, but it's an awesome project!)


Here you can see how I have Extract's Auto Markings turned on when extracting.
At the end, after I have applied the seam allowance's [A = 0.0] seams, you can see one little screw-up as the bezier curves hit the line. That is the "confusion" I was talking about up there. I'm selecting this little line and moving it around, just to see what it is. Having made sure it was just a stray allowance rest (marking), I just deleted it.

Working with multiple polygons inside one patternpiece can still baffle our seam allowance feature. It is something we still need to tackle, but it's also rather unusual and easy to overcome in the meantime by simple having two patternpieces. In your case there, though, you most certainly shouldn't have to have the dart as an extra polygon. But I did find it fascinating how insanely seam allowances freaked out then... :? :bl: ...hmmm.
AmosG
Posts: 6
Joined: Sun Sep 05, 2021 11:28 am

Re: seam allowance tool adding unexpected lines

Post by AmosG »

Thanks, I appreciate the help.
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