Akima spline curves give drawing freedom, at least some kind of interpolating 
spline curve where you can just simply lay the points down and the curve 
follows along the points - I have a hard time getting bezier curves to do what 
I want.  It's like Alice in wonderland using a flamingo for a mallet in a game 
of croquet. unweildly.

Bezier Curves were introduced into Windows NT.  It seems like a lot of paint 
programs began including Bezier Curves as a drawing method after that.

They should have also introduced Akima spline curves into Windows. I am not 
saying take Bezier curves out - I am saying Add Akima Spline curves, or the 
bettered (modified) version of Akima Spline curves that doesn't react as much.  
At least some type of interpolating spline curve where you just lay the points 
down and the curve follows the points.

Akima spline curves are cool.  just put points along where you want the curve. 
simple.  you just need more points around sharp edges, or you get a "ringing" 
effect around that area. (See discussion and visuals link).

part of the challenge of using Akima spline curves is that the first 2 data 
points must be faked or dropped.  same goes with the last data point.  this can 
be taken care of with some simple engineering tricks.

Wikipedia article on Spline curves (mathematics). This does not cover the Akima 
Spline, which 

keeps its curve along the data points rather than just near it like a B-spline 
curve does.

demonstration of the various curve types in action. (requires Java) play with 
the spline curve for 

a while (delete the existing points other than 0 first to get started)

B-Spline curve with Knots (can be active demo) 

GNU Scientific Library Reference Manual 
book - has Akima Spline & Cubic Spline. See also 
GNU Manual

PDF file from medical site on akima and spline methods and its associated 
errors. Recommendations 

for fixing the significant overshoot on abrupt changes, and suggestion to use 
more closely spaced 

points around those regions. must purchase.

The Akima Univariate Interpolation Method (spline) article from the acm. by 
Hiroshi Akima. 

requires web account and probably money to buy the PDF article.

Equations for Akima Spline

http://www.alglib.net/interpolation/spline3.phpdiscussion and visuals of Akima 
Spline and its 

drawbacks. also has source code in C++, C#, Delphi, VB6, Zonnon.



pay-for article on some sort of improved-smoothness spline. Shape of data is 

MATLAB model.

Jim Michaels

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