Equation Of A Spline that passes 4 points

[tomtomtom]

Hello all

I was hoping someone could shed some light on the following:-

I have a spline that goes through 4 points:-

x1,y1 - x2,y2 - x3,y3 - x4,y4

The spline is of degree 3 and is fixed at points x1, y1 and x4, y4.

What i need is the equation of the spline.

Is there anyway of calculating the equation that represents the spline?

Thanks

[Organic]

It should be possible, although it is a huge pain to do so. I remember having to do it back in college, although have never used it since.

The general method is outlined in http://mathworld.wolfram.com/CubicSpline.html