Hello edvinasaplanga, you have just uploaded a file showing how to develop a "tube slash cut plate".I do this with a LISP file that can do it automatically, you enter the 3 specific dimensions and the LISP file do the rest.I can also ( and it's the same curve type ) draw a "sinusoid" curve with entering the characteristic 2 dimensions. Do you draw the SPLINE " by hand" or with a "program" or LISP file ?