I would like to share a fun little project that I have been working on lately.
The thing that has bugs me about all of the major board design applications out there is the fact that they all use splines to define the curves of a board. Splines are great for defining any shape under the Sun, but they are just too complicated IMO. You always have to start out from some predefined template, and modify it from there. If you want to change something you can’t really quantify the change. You just click and drag until you think it looks right.
I have been mulling over an idea of a way to create a set of templet’s for a HWS style board. I’m going to apply this technique to my next project. I’m currently in the process of designing the ribs for the internal skeleton, and was thinking about how to do it. At first I was thinking about using parabolas, and posted a question on PysicsForums.com. Here is a link to my post: http://www.physicsforums.com/showthread.php?t=243453. Someone gave me a suggestion to try the hyperellipse function instead. This simplified the problem a lot, and I got to work writing a Perl script to automatically generate cross section templates using hyperellipses.
The hyperellipse is a type of superellipse. You can read more about it here: http://en.wikipedia.org/wiki/Superellipse
Here is a graph that shows you the general concept.
The blue curve on the top is one half of a hyperellipse that defines the deck of the board. The orange curve on the bottom is half of another hypereillipse of the same width.
Here are the parameters that I used to defined the above shape.
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Width of the cross section: 20 inches
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Thickness of the cross section: 3 inches
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% of total thickness from deck: 70%
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Curvature constant for the deck: 3.5
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Curvature constant for the hull: 5
That’s it! Five parameters is all it takes to define the shape of a cross section. I think that the shapes produced by this function are very well suited for rail, deck, and hull design. The area where it isn’t so good is if you want to add V to the bottom or concaves. I don’t really see that as a drawback, though. You can always hand shape those features into the board. I don’t think this will ever replace spines in any of the major board design applications for machine shaping purposes. I am just interested in creating templates, and this is plenty useful for that.
Attached is a sample PDF template that I created with the Perl script that I wrote.
p.s., I have already finished my rocker and board profile temples based upon another Perl script that I wrote a while ago. This post is meant to cover the cross section design. I’ll provide details for that other stuff later.