I know how to do this manually, but I need an automatic way (either a script or just a command in Illustrator).

Here's a line like the one I mean. Notice how it's all made of straight lines (The blue dots are the anchor points):

enter image description here

How can I turn this into a true curve easily?

Note that I have all of Adobe Creative Cloud at my disposal, so if there is a tool in Fireworks, Photoshop, or anything else that can help, it is still relevant.

5 Answers 5


You can try Object > Path > Simplify and adjust the Curve Precision and Angle Threshold settings to perhaps get a curve.

There's no straightforward method, which I'm aware of, other than this.

  • Worked great! It actually did just what I wanted.
    – sinθ
    Commented Jun 27, 2013 at 19:56
  • Many times, if you don't have an actual distinctive curve in your straight-lined path, this method won't work so well. For instance, using a path more like what @user56reinstatemonica8 wrote below this wouldn't work.
    – CU3ED
    Commented Jun 29, 2020 at 15:23
  • I never posted this solution works for every possible situation. It merely works for this situation. The down vote was, well, a bit unwarranted in my opinion.
    – Scott
    Commented Jun 29, 2020 at 16:39

There's also the Smooth tool enter image description here if you prefer a more hands-on approach. Rub it over a selected path, and it smooths it where you rub. If it doesn't smooth enough, keep rubbing.

From this tutorial:

enter image description here

enter image description here

Double-click the tool icon to set how closely the smoothed line sticks to the original (fidelity) and how strong the smoothing is each time (smoothness).

A nice additional feature of the smooth tool is, it only applies to paths and points that are selected. So, if there are parts of a path you want to stay exactly how they are, and parts you want smoothed, you can select just the points you want to be smoothed then use the smooth tool.

  • Thanks. I'm pretty new to Illustrator. I've been using the Direct Selection Tool (A) & Delete Anchor Point Tool (-) to clean up huge, complex traces. It's been taking forever, so this is such a relief.
    – voices
    Commented Oct 9, 2018 at 16:27

Select the path that you want to convert and with the direct selection tool and the shift key pressed, exclude one point. Some new buttons appear under the menu, one of them is to convert selected anchor points from corner to smooth.

enter image description here

  • Thank you for posting this answer! I believe with many different paths, for example drawing a map with roads, this is the best method. It's the quickest and most efficient, you don't need to switch from the pen tool to another tool (smooth tool) and once you get the hang of it on which nodes to click, it gives almost perfect results.
    – CU3ED
    Commented Jun 29, 2020 at 15:25

After you have done Effect > Stylize > Round Corners. Then go Object > Expand appearance to create a curved line that is editable with handles.


Effect > Stylize > Round Corners.

  • 1
    This will not turn the lines into a single path, it will just round out the edges.
    – Hanna
    Commented Mar 18, 2014 at 1:24

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