A couple of days ago I asked how I could draw a SMOOTH line trough a couple of points, and I got 2 answers:
-B-spline who cuts corners until the line is smooth (so the line doesn't go though the points)
-Cubic-spline cut draws a lot of separate functions of the seconds order (a*x**2 + b*x + c) which means that the second derivate has jumps in it. For airfoils this is unacceptable because the 2nd derivate should be smooth too so that the air going arround it would be laminar.
The B-spline is smooth enough, but doesn't GO THROUGH the given points, which means our airfoils changes. (=unacceptable when you are looking for performance)
The second one is not smooth enough.
Does anyone know an algorithm that draws a line that is as smooth as the B-spline and still GOES THROUGH the given points (which are in line)
I have built a foam-cutting machine which is computer controlled. Now I just need to draw this SMOOTH line through a series of 15 to 100 points. Out of these 15 to 100 points I should compute about 500 to 1000 points to match the foan-cutters accurancy (2 points mm)
There are some software (freeware) on the web like WINFOIL and others who do the job for a regular printer, so it should not be so difficult. (only they don't give there codes away)