# Airfoil

I wanna make a program that draws an airfoil given a number of point (eg 20 points on the airfoil)

How can I program a SMOOTH line through these points?

I tried to find the line y = 1 + x + x**2 + x**3 ....
via the Reduced Row echelon Form of a matrix, but it is not a good option.
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Commented:
You can find lots of information about the B-spline (I don't know the exact algorithm) which paints a smooth line using a set of control points. It does not have to pass through these points, however. I don't know if that is what you need...?
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Author Commented:
Sounds great:

Just need an algorithm to draw a smooth line through a set of points. (to draw an airfoil)
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Author Commented:
B-spline does not go through the given points,

do you know any other that does ??
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Commented:
Almost no algorithm make the curve to touch control points (in fact, the smoothing process means that a bit). If you have a curve with these (numbered) points, it's impossible to draw an INNER curve (this is, not going BEYOND control points), as a Spline curve does, which touches all four points:

2 .
1 .                4 .
3 .
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Author Commented:
it should not be an inner curve at all. That's what the B-Spline does. This means that our airfoils would become smaller than they should be.
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Author Commented:
Perfect, that's exactly what I was looking for.

Now I just have to write some code who does the thing, and it might not be easy,