Through other software I managed to obtain a spline with length of 200mm. [![enter image description here][1]][1] The points would be these: pts = {{0, 0}, {45, 10}, {75, -15}, {130, -20}, {180, -33.25904873}} The last value in Y (`-33.25904873`) is not accurate for this directly depends on the length of the spline, that is 200. 1. I get this value in the SolidWorks software, but how can I get this value using Mathematica? And another question: 2. There is only one solution or there may be several other? [1]: https://i.sstatic.net/lxEn8.png