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I am trying to trace a curve using the path tool, which you can just about see in the image. I have also attached the xcf file.

To get an accurate trace I found that I needed to make a path with several segments. It is quite difficult to get the segments to join up smoothly without a kink in the curve where they join. Is there an easy way to do this? Or a better way of tracing the curve?

[attachment=1309]
Im using the clock method most of the time. Meaning, you create anchor points at the most extreme point, like "top of mountains" and "bottom of valleys" (not sure what the correct term is in english....vertex ?).
You can use this technique in combination with dragging to make a curve or without.

After you set the anchorpoints, you tweak the handles.
Holding down Shift helps keeping the handles on both sides symetric.

Also: handles should follow the direction of the line for a bit.
To avoid bumps, make sure the handles on both sides maintain a straight line, otherwise you will get a corner.
As

[attachment=1312]

There are favourite ways to get started but the end result is the same.

A 2 minute video on the example(s)  https://youtu.be/oMZfDyzJzTQ

There is a plugin to smooth a path but in this case not much help.
(01-15-2018, 01:16 PM)Espermaschine Wrote: [ -> ]Im using the clock method most of the time. Meaning, you create anchor points at the most extreme point, like "top of mountains" and "bottom of valleys" (not sure what the correct term is in english....vertex ?).
You can use this technique in combination with dragging to make a curve or without.

After you set the anchorpoints, you tweak the handles.
Holding down Shift helps keeping the handles on both sides symetric.

Also: handles should follow the direction of the line for a bit.
To avoid bumps, make sure the handles on both sides maintain a straight line, otherwise you will get a corner.
  • I do the opposite, I tend to put the point on the curve inflexion points.
  • Yes, using Shift to keep handles symmetric and colinear insures a smooth curve
  • For the curve below, position 4 points, two at the ends, one on each side of the sharp bend
  • Adjust the tangents on the inner anchors to follow the bend (holding shift for symmetry)
  • Adjust the tangents on the end points to follow the rest of the curve
(01-15-2018, 02:05 PM)Ofnuts Wrote: [ -> ]I do the opposite, I tend to put the point on the curve inflexion points.

The complexity of that technique is higher. For a beginner it might be hard to decide where to put the two nodes and not to create an (even slight) corner.
Or maybe i dont understand the concept of the inflection point fully.....
Thank you all, that helps a lot.

I didn't know that holding down the shift key keeps the handles on both sides symetric, that is the most important thing that I was missing.

Thanks!
(01-15-2018, 02:29 PM)DavidCheshire Wrote: [ -> ]I didn't know that holding down the shift key keeps the handles on both sides symetric, that is the most important thing that I was missing.

Its always good to check the manual:

https://docs.gimp.org/en/gimp-tool-path.html

Even after many years of using Gimp, i can find something new and useful there.
You are very right, my apologies.

In fact, I have read that section of the manual several times but that point didn't register - sometimes an explanation is only completely clear when you already know it.

Regards, David
I did not mean that as criticism. When nobody asks questions, this forum will become obselete.
Talking about different techniques is always useful !
Its just that some people seem to not know about the manual.
(01-15-2018, 03:09 PM)Espermaschine Wrote: [ -> ]I did not mean that as criticism. When nobody asks questions, this forum will become obselete.

Yes, this is the "StackOverflow" paradox. There are some question-correctness-fundamentalists out there, and to be able to create a question by their standards you have spent so much time searching it that you have found the answer.
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