Bezier spline

[EEL1966]

This is my first post so I hope it is at the right place.

I would like to make my own Bezier spline however I have a problem. I don’t know how to find the control points

I have 4 points in x,y and I would like to find y for a given x value between point 2 and 3. As I have understood it a Bezier curve is made using

starting point (t=0) (point A, see link below)
ending point (t=1) (point D, see link below)
2 control points (point B and C, see link below)

http://www.blackpawn.com/texts/splines/

My question is how do I find x,y for the 2 control points based on the 4 regular points?

Thanks in advance

 

[Deleted member 4993]

This is my first post so I hope it is at the right place.

I would like to make my own Bezier spline however I have a problem. I don’t know how to find the control points

I have 4 points in x,y and I would like to find y for a given x value between point 2 and 3. As I have understood it a Bezier curve is made using

starting point (t=0) (point A, see link below)
ending point (t=1) (point D, see link below)
2 control points (point B and C, see link below)

http://www.blackpawn.com/texts/splines/

My question is how do I find x,y for the 2 control points based on the 4 regular points?

Thanks in advance

Have you studied Bezier spline mathematically? - that is a at least 4 lectures in numerical analysis!

What degree of spline do you want to use?

 

[EEL1966]

I am making the spline functions for Excel and I have tried different type, the last one I tried was a Catmull-Rom spline and I would to test Bezier to see if it is better for my purpose. With two control points I believe that it is a cubic Bezier curve.

I have looked on the internet, not studied it in detail, and what I have seen is that in most cases the control points are treated as known. I have not found any place where the calculation of the two control points is shown.