Jim Michaels ([EMAIL PROTECTED]) wrote:
> 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.

Oh well, that all kind of depends on how you implement it. In the Curves
dialog we also use bezier curves and you don't really notice it, because
the control handles get determined automatically.

> 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.

Bezier Curves have a lot of (computationally) nice properties, making it
easy to implement it. Plus it really is nice how you can control them in
quite detail.

> 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).

Yeah, just laying down nodes is a cool way to edit curves. From your
links it seems that Akima-Splines have a better locality and are more
stable than e.g. Spiro curves.

The thing is that there are dozends of interpolation types that have
this "laying down nodes" editing property and it is hard to put a finger
on which one to choose. We do know that spiro curves have been developed
to create visually appealing curves by requiring certain smoothness
properties. That makes them an appealing choice for design oriented
programs. The instability of spiros however might kind of hamper their
adoption for real use though.

Do you know of any study on how suitable Akima splines are for graphic
design? It would be nice to have a comparison of different spline types
for this kind of application. I believe the criteria you mentioned above
(locality, interpolates all control points) are not necessarily enough
to judge on that.


              [EMAIL PROTECTED]              http://simon.budig.de/
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