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I'm trying to draw a rose curve using the function plotter in inkscape.
It should be in polar coordinates. I'm using the function cos(3*x).
I want to achieve a result like this.

I'm stuck with the following result which is incomplete:

enter image description here

The curve is not closed. The two "leaves" on the left side should end up in the center.

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  • Decrease the start value until it fully completes the loop. Something like -2.2 should do the trick. You probably also need to increase the number of samples for more accuracy.
    – Billy Kerr
    Commented Apr 13 at 17:36
  • This also is a solution. Increasing samples gives better results. The accepted solution needs even higher number of samples to give good results
    – sthag
    Commented Apr 13 at 20:54
  • No need for too many samples. 25 should be fine, and with a few more tweaks will give an almost perfect result see example
    – Billy Kerr
    Commented Apr 13 at 22:42
  • Also is there some reason you need to use a plot for this? For example does it have to be a mathematical curve, or is this just for a graphical effect. To be honest, there are easier ways to make repeating loop patterns in Inkscape. The Rotate Copies LPE for example.
    – Billy Kerr
    Commented Apr 14 at 10:45
  • @BillyKerr Thank you for all the additional information. I thought using the function plotter gives the best possible shape. I am only looking for a graphic result. Also the german translation is a bit misleading according to samples used, imo. I did not expect sampling to have such a great influence on the result, or that it is even necessary.
    – sthag
    Commented Apr 14 at 15:46

1 Answer 1

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You seem to want a polar plot. X means the angle and Y means the radius. The angle covers a single turn (that's exactly 2Pi radians) if the X range is from 0 to 1 and option X is multiplied by 2Pi is ON.

An example (5 petals with cosine function):

enter image description here

Some general information

As said in the linked Wikipedia article, more complex, but regular looking variations of the same curve idea can be got by using rational number factors for X. In the next example the factor of X is 2/3. To cover the whole curve the X range must be 0...3 (the endpoint=the denominator of the factor).

enter image description here

The linked article of rose curves has this summary image:

enter image description here

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