Ecacytly
old axiom of mine: ‘‘Let the ideal curve dictate the numbers. Don’t let the the ideal numbers dictate the curve.’’
The challenge, of course, is being able ‘‘see’’ that ideal curve.
Bypass the arcs (to avoid corners) and go straight to the elipse , so you can keep the dimensions as intended.
Exact!
Where do you want to end up? What do you want to create?
If making your surfboard is more of an artistic expression, poetry in a physical form, art for art’s sake, then Malaroo’s method is a thing of beauty. Haiku in watercraft.
On the other side, if it is function, the fastest turning highest speed, barrel riding rocket ship you want, then arcs and ellipses are a tool to creating a curve, but shouldn’t limit the design.
If I know that a 12" nose, and a 20" wide point, 2 inches past center, with a 15" tail will surf the best, then loosing that for the sake of a mathematical formula is taking a step backwards.
My first post on arcs makes the surfboard shape that I am after. Which has the correct surface area where I want it, with a very smooth outline. When I drew an ellipse to cover it, it smoothed out the template, but lost a little bit in the accuracy of the widths I was after. Better or worse? I’m not sure.
But either way, it is a pretty cool idea to have in your toolbox.
Me too Hans…numerology is something I believe in , as a means to document and compare anything from the Mona Lisa to a surfboard…there is , without doubt , a set of numbers that tie everything together in many ways , to create proportions that are pleasing to the human eye…and .the same set of numbers relate to function…a well made surfboard is a classic example.
I fully agree.
But even the first surfboard shapers had their ways to parameterize their shapes.
Designing surfboards is trail and error and it will always be like that. It is all a matter of reducing the number of parameters, to a meaningful set of base parameters.
The more experienced the shaper, the more parameters he can handle (but that doesn’t mean he should).
Malaroo just describes a very nice way of parameterizing the shape of his boards. Nothing more, nothing less.
But I’m really impressed by the mathematical beauty of his method.
…as fascinating and relevant as the “geometry thread” is , it should not be forgotten that it would not exist without the surfboard builders through many years that developed by eye , what we regard as a surfboard…and most of them did not rely on geometry , they just wanted better performance from their boards , and the main ingredients were common sense , hands-on practical craftsmanship and Mother Nature to achieve it…it actually began quite a few thousand years ago.
thanks Hans
Your threads are fantastic too!
The geometry thread blew my mind!
It is fantastic!
Chris,
The first couple of pages from back in 2004 were amazing.
Thanks chrisp , yeah that’s the thread…I found it interesting and remember thinking at the time, that any plan shape could be generated , by varying the diameter of the cone or cylinder , and the length , and changing the angle of the slice…the basic point being , that at no point can a compounding curve ever be the arc of a circle…it’s physically impossible.
There was a thread maybe a year back , started by a guy who was taking angled plane slices through cones to generate irregular elipses for board outlines (computer generated)…can’t find it , but it’s there somewhere…its quite relevant to this topic , as it generated compound planshapes , to a W/P and nose and tail measurements…
ES, I like what you did to the right-hand side in the ellispe version, the extra fairing really looks good to me.
{human} masonite vs. computer.
With regards to keeping a couple tails and my favorite driver outlines, I’ve fully switched over to computer-driven curves as of yesterday. The computer is a tool. I’m still hand-shaping in the end. And in order to build, you need tools. Cool thing about virtual tools is I get way better looks at my upcoming hack jobs. So, I’m for the machine. But no regrets learning how to get tempered hardboard curves smooth. It was a worthy venture, I learned some things about hand-building outines doing this, but now…all paper outlines. Faster, more affordable, the paper recycles and it keeps my shaperoom free of brown dust resets less often. Not to mention a more creative workflow and more workspace**.** Leaner, meaner.
I use a large format printer to print full size. You can get them pretty cheap on e-bay
Hi Jrandy,
I started out using the spline tool, and it just isn’t that accurate. You want to shape to an exact design and the spline tool kind of does what it wants. Also the spline tool can create flat spots and exaggerated curves as it averages out the points you lay down. If your points aren’t good, Spline will still follow them. Arcs and ellipses will take your input and force a smooth curve. While spline lets the points govern, and ellipses takes your points as a “suggestion”.
Use Ellipse Arc and not Ellipse Center Tool.
Too much inside baseball on AutoCAD for here, but if you give me your email via p.m. we can go into more detail.
ES, have you tried a spline command in AutoCAD? It makes a smooth curve between control points, like where you measure the board on the ends and 1' from nose nose, wide point, 1' from tail of a board. You can manipulate the start and end tangents and/or add extra points to lock in a design. I do this and then quarter the outline and make a spin template all on screen that only needs 1/4 of the area of the board in paper. I add marks for selecting print areas and re-aligning the pieces. No trips to the print shop, no masonite is harmed, just run a soft pencil along the cut edge of taped-together papers.
This is a good discussion, thanks for keeping it going.
Holy crap. Yorky and Hans have individually blown my mind in the span of the 2 minutes it took me to read through this thread.
The drum idea: stinking brilliant.
The woodworking ellipse thing: how have I never heard of this before?
Years ago I went through this exercise with a compass made of electrical conduit Tap-conned to my warehouse floor. I made a series or radius templates up to about 40’. Afterward, though, I never found them particularly practical, as almost all the curves I want to make are elliptical. I’m not knocking the idea. Just sharing my own limited experience.
I would think they have more merit when designing longer, gunnier shapes. However, here on the Gulf of Mexico, those kinds of boards are used rather (ahem) infrequently.