Hi Ali,
I understand that you want to you want to draw a B-spline curve using de Boor’s algorithm with the knots being same as that of the cubic spline.
The number of knots is the minimum for the degree of the B-spline curve. After looking through various sources, I found a few useful links. They are as follows:
http://www.mathworks.com/matlabcentral/fileexchange/27374-b-splines - This package activates a figure window to place B-spline control points interactively and see how the curve is drawn.
http://booksite.elsevier.com/samplechapters/9781558607378/9781558607378.PDF - This chapter talks about B-Splines in an extensive way.
Hope this helps.
