Difficulty to select a portion of an arc when line cross portion of arc

Documentation / How to
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First, I really love this software. I start using it few days ago and it is just great. So really appreciate the effort you put on it and on the assistance provided through the forum.

I have an issue that I could not locate solution to on the forum. When trying to select an arc to a piece, I have only a piece of this arc being selected if a line cross the arc. I could not find a way to select the portion of the arc on the other side of the arc portion already selected. I try to add nodes to the path, without success. A pdf attached will help understanding the issue. Tks Seamly anomaly.pdf (395,7 Ko)

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Have you tried to turn around the curve Arch_A_4?

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Can ypu post the pattern?

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Tks. 2 files attached. I thought I was doing something wrong in my blank bucket hat, therefore I produced the test, much simpler, with which I got the same issue. test.sm2d (5,0 Ko) Blank Bucket Hat 1.sm2d (16,1 Ko)

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Yes, tks. I tried it. I succeed to select the piece path as long

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Ok… it’s what I thought,but without the pattern I had no way of knowing what angles the arcs start and end. Has nothing to do with Line_A_A1.

This works because the arc segments are fully within the 180 to -180 range:

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This doesn’t work because the arcs are split in 2… from A4 around to the start of the arc, and from the start of the arc to A5.

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Moving the start amd end angle so it falls in between works:

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Here I formulized the start and end angles by adding & subtracting “0.1” from the start (175) and end (160) angles of what will be the angle of the intersect axis - so we insure an intersect:

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and now there is no issue:

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Just be aware that if your SA overlaps at the ends, it’s going to mess up because now the whole inside is considered SA:

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Tks a lot Douglas. Happy that there is a solution. I just need to digest it, that I will do tomorrow morning. I love seamly2D but started recently and needs practice :wink:

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