# Joining curves sometimes creates two vertices on top of each other. But sometimes it isn't. Why?

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Hello,

Sometimes when I want to join two curves, the join results two vertices on top of each other. The vertices do get joined, but in a way that two vertices end up being right on top of each other. At other times, however, the curves do end up joining at a single vertex. I cannot figure out why this is.

In the attached video, I provided some description at the top. I am trying to join to ellipse halves. In the first case, I re-use the de-attached bottom curve and they do get joined in a single vertex.

However, in the second case (on the right), I delete the lower half of the ellipse and duplicate and rotate the top half. When I try to join them, they do result in two vertices being on top of each other. Don't really understand why this is. What is the logic behind this - if any? Thanks.

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Hi PenTool,

This is currently a known issue and should be improved in a future update.

Thanks

C

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Well - he tries to join two start/end nodes (red/blue marker)  - if one became reversed the joining works - fiddly but explicable. (Not that any other vector app I use do the same 😉)

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1 hour ago, PixelPest said:

Well - he tries to join two start/end nodes (red/blue marker)  - if one became reversed the joining works - fiddly but explicable. (Not that any other vector app I use do the same 😉)

That's a pretty ingenious explanation, but there must be more going on here. When I try to re-create the OP's experiment it works perfectly every time: always a singe vertex, never a double (that's even when flipping the half-circle vertically or horizontally, or reversing the path direction). However, doing the same experiment with sharp nodes (i.e., drawing a square, converting to curves, and adding a (centered) node to the top and bottom segments of the square) results in double vertices every time, regardless of flipping, reversing path, etc. And I've definitely ran into the doubled-vertex problem when joining sharp nodes before, while using the software.

iMac (Retina 5K, 27-inch, 2019)| MacOS (Probably latest stable build)

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From further testing: Set the Cap: Round Cap and Join: Round Join at Stroke style before drawing the circle. Good luck.

Then try with Round Cap + Bevel Join.

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9 minutes ago, PixelPest said:

From further testing: Set the Cap: Round Cap and Join: Round Join at Stroke style before drawing the circle. Good luck.

Then try with Round Cap + Bevel Join.

I get the same results with Cap: Round Cap and Join: Round Join at Stroke style before drawing the circle as I do with Cap: Round Cap and Join: Bevel Join at Stroke style before drawing the circle: single vertex every time.

iMac (Retina 5K, 27-inch, 2019)| MacOS (Probably latest stable build)

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That is so strange - I recreated it 5 times to be sure - every time the same result - when I start to record the steps I got the other ending story:

So here I can me watching scrolling through my history to give you an idea:

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Yup, strange indeed. BTW, are you on Windows? I ask because : 1) I'm wondering if that makes a difference, and 2) I'm envious of your thicker-stroked red/blue end nodes. I frequently run into the winding/non-winding problem because I can't tell which end is blue and which is red (in the video, they're set on "Largest" in the tools preferences).

iMac (Retina 5K, 27-inch, 2019)| MacOS (Probably latest stable build)

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