Offset curve
From TOI-Pedia
If you want to create a copy of a curve that is complete parallel to its original, the regular scale option does not work well. Thus we use the offset option, which can be found under Edit Curves > Offset > Offset Curve. The offset option makes a copy of the original that is at equal distance from the original along the entire curve.
The option box for this command offers a lot of options, which can be overwhelming. It can be easier to just hit offset, and later, with the use of history, change the distance of the offset (see example below).
Sometimes this does not give a satisfying result and you do have to use the options given by the option box.
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