23 or 24
Moderator: Moderator
- kidrock
- Legend (Contribution King!)
- Posts: 619
- Joined: Mon Nov 29, 2004 9:51 pm
- Location: about to open up a Can
Re: khgs
CaptKneemo wrote:after trying fish from 21.5 to 25.5 and being a big feller, i figger 22-22.5 is great for me. it does everything i want a fish to do. other styles of boards? i've tried a bunch, oz boards, hawaii boards and cali boards....there is no absolute truth in width, length, thickness, outline, rocker, kick or fin placement. experimentalism IS THE ONLY ABSOLUTE!
I'm gonna agree with The Krusty One here. A lot of boards over a lot of years, different shapes, different sizes, thickness etc.
I'd be more concerned with the shaper than the actual shape. Every single one of us has been down that road before...more than once
Experimentation is, and always will be, the kneeboarder's creed. Find what works for YOU, and enjoy. Isn't it great to not be a sheeple?
Ken you are correct.
However you can hold very similar / exactly the same outline at different board widths by stretching apart the curve join at the nose and tail.
Instead of having the rail curves cross at the nose and tip, it's possible to insert a bit of flat edge. Since we're only talking 1/8-1/2" you can't really pick a squared off nose or tail once it's blended in. Even 1" square nose is hard to pick on a 18.5" nose board.
Most shapers use two half curves and blend the at the midpoint (so you can often see the flat or a wobble where the curves join, depending on how good their lofting is). Since all my outlines are pure curves (one continuous curve nose to tail) it's useful for me to use this technique to play with widths without altering the purity of the outline curve.
However you can hold very similar / exactly the same outline at different board widths by stretching apart the curve join at the nose and tail.
Instead of having the rail curves cross at the nose and tip, it's possible to insert a bit of flat edge. Since we're only talking 1/8-1/2" you can't really pick a squared off nose or tail once it's blended in. Even 1" square nose is hard to pick on a 18.5" nose board.
Most shapers use two half curves and blend the at the midpoint (so you can often see the flat or a wobble where the curves join, depending on how good their lofting is). Since all my outlines are pure curves (one continuous curve nose to tail) it's useful for me to use this technique to play with widths without altering the purity of the outline curve.
Pure curves are an ANALDOG (analogue) concept Eg: Sinewave
Digital curves are stepped as in a curve with bits missing
Much study has come from a mathematical and computational perspectives. In particular the symmetry of surfboards is a newly-developed field.
Curve patterns created well before the mathematical study of surfboards can be understood and classified using relatively recent mathematical notions of symmetry.
The concept of a smooth and "nice" curve can be formalized using the concept of a fair curve from the calculus of variations. A fair curve minimizes a functional, or some measure of the energy along the curve.
This technique of computer-aided design is motivated by historical practice in design, where physical elements like pieces of wood were used to generate shapes. A piece of wood attached at several points will form a curve that minimizes its strain energy. I use the functional from [Moreton 1992], the squared magnitude of the derivative of curvature. This generates minimum variation curves.
Using finite differences I calculate an approximation of the derivative of curvature for a piecewise linear curve. I simply ignore derivative of curvature approximations which include elements from both sides of the curve, effectively breaking the curve into two segments. And the final user-specified constraint, setting the angle that two curves should meet at a sharp vertex is enforced by adding an additional force that penalizes departures from the constraint. This penalty-method approach has the disadvantage that it doesn't satisfy the constraint exactly, but it had the advantage of simple implementation. In order to speed up the optimization I begin with a low resolution curve and go through some gradient descent steps before subdividing the curve and repeating.
Digital curves are stepped as in a curve with bits missing
Much study has come from a mathematical and computational perspectives. In particular the symmetry of surfboards is a newly-developed field.
Curve patterns created well before the mathematical study of surfboards can be understood and classified using relatively recent mathematical notions of symmetry.
The concept of a smooth and "nice" curve can be formalized using the concept of a fair curve from the calculus of variations. A fair curve minimizes a functional, or some measure of the energy along the curve.
This technique of computer-aided design is motivated by historical practice in design, where physical elements like pieces of wood were used to generate shapes. A piece of wood attached at several points will form a curve that minimizes its strain energy. I use the functional from [Moreton 1992], the squared magnitude of the derivative of curvature. This generates minimum variation curves.
Using finite differences I calculate an approximation of the derivative of curvature for a piecewise linear curve. I simply ignore derivative of curvature approximations which include elements from both sides of the curve, effectively breaking the curve into two segments. And the final user-specified constraint, setting the angle that two curves should meet at a sharp vertex is enforced by adding an additional force that penalizes departures from the constraint. This penalty-method approach has the disadvantage that it doesn't satisfy the constraint exactly, but it had the advantage of simple implementation. In order to speed up the optimization I begin with a low resolution curve and go through some gradient descent steps before subdividing the curve and repeating.
Last edited by budgie on Thu Aug 20, 2009 12:54 am, edited 1 time in total.
I think the link to Virgin Mobile was an accident
rather than use a derivative to look at changes in curve
I alway thought it might be cool to use Wavelets Math
cos we like to ride waves
Often Wavelets Math is used as an alternative to Fourier Transforms
It's something Electronic and Audio Engineers use to look at waveforms and harmonics and distortion etc
http://www.answers.com/topic/wavelet
perhaps it can be applied to water waves and fluid flow and curve ..... I have a head ache now
....
and need to rest
bummer
Budgie already posted ... it took me too long
I got it Greg
rather than use a derivative to look at changes in curve
I alway thought it might be cool to use Wavelets Math
cos we like to ride waves
Often Wavelets Math is used as an alternative to Fourier Transforms
It's something Electronic and Audio Engineers use to look at waveforms and harmonics and distortion etc
http://www.answers.com/topic/wavelet
perhaps it can be applied to water waves and fluid flow and curve ..... I have a head ache now
....
and need to rest
bummer
Budgie already posted ... it took me too long
I got it Greg
-
- Ripper (more than 100 posts)
- Posts: 181
- Joined: Sun Jul 27, 2008 6:51 pm
- Location: New Zealand, Tauranga
-
- Ripper (more than 100 posts)
- Posts: 181
- Joined: Sun Jul 27, 2008 6:51 pm
- Location: New Zealand, Tauranga
Hi Greg
When first I started to read the post I thought you were for real , got part way thru and was really impressed at your mathematical knowledge and amazing vocabulary . Knew there was more to you than a wry smile and a sore back.
About half way thru I thought "bulls**ting Bas***d". Man he took me for a sucker.
Good onya bro.
When first I started to read the post I thought you were for real , got part way thru and was really impressed at your mathematical knowledge and amazing vocabulary . Knew there was more to you than a wry smile and a sore back.
About half way thru I thought "bulls**ting Bas***d". Man he took me for a sucker.
Good onya bro.
Live for the moments that take your breath away.
kneed for speed
kneed for speed
Re: 23 0r 24
[quote="budgie"]Hi Jackson
Tail and nose 12inches up is 18 1/2 inches wide.
I like symetrical sort of boards and numbers, hope that helps.
Will post some pics of board soon
Budgie[/quote thanks buddy
Tail and nose 12inches up is 18 1/2 inches wide.
I like symetrical sort of boards and numbers, hope that helps.
Will post some pics of board soon
Budgie[/quote thanks buddy