Jim and Jerry, Thanks a lot!
From Dave Branden example I learned that "the secret" was to use an array
formula.
I coded my algorithm in VBA and it works as I wanted!
Thanks again.
Fabian


"Jerry W. Lewis" wrote:

David Braden has posted code for cubic splines
http://groups.google.com/group/micro...2966520eccdb1f

If you are interested, the Excel chart smoother appears to use Bezier curves
http://www.xlrotor.com/Smooth_curve_...ample_file.zip

Jerry

"Fabian Grodek" wrote:

Is there any way in Excel or VBA to do a spline approximation to test data
that do not follow any polynomial shape? I mean, I have data points and I
want to approximate (i.e., not necessarily pass through the points) that data
with a spline curve.
Thanks.

Fabian