Your elevation ticks are way under sampled. There are many curves that can fit the data( plan view) you have presented. If you want just a picture then what Dave has shown is great but if its use is for some real world application then you will have to establish some criteria on the spacing of you elevation samples and usually based on some type of rms error etc.

Hi, the next three possibilities. what I still don't understand is how do I control the length of the curved object? I posted this also here http://forums.sketchucation.com/viewtopic.php?f=323&t=18210&start=600 Charly Sail.skp [image: BO7C_Unbenannt.JPG] [image: atac_Unbenannt.JPG]