Lay out a sine curve?

[Leon]

Perhaps Arcs rather than an ellipse. An Ellipse is very much like a sine curve/wave.

[Doug Miller]

Well, sort of... This isn't a sine curve, but it's attractive, and easy to lay out with a disk:

[Larry Bud]

Found this for ya

[Oleg Lego]

The Guess who entity posted thusly:

Sounds interesting, but I have not been able to find it. Is that name correct? If so, would you happen to know what directory it's in?

Thanks.

[Guess who]

The address is correct:

right, Software section, click "Windows...." Choose "Graphing programs", and there find Graphmatica. It's labelled as shareware, but the author generously offers it free if not affordable.

Click that, then choose grmat16n.zip for the latest Windows version. It will do for the shop, for the kids in high school, or in college and university. Type in a function as done normally: e.g. y =

2sin(x), no need for 2*sin(x) etc.. You can graph an ellipse as well, but that can be done as readily, and to scale in a simple but powerful CAD such as DeltaCad.

Default is a coloured background, and coloured curves, but you can change that to white. You can do more than one in one shot. Tons more software there, but not for this forum. I just mentioned it for anyone wanting some usual or unusual math curve.

[Enoch Root]

[Oleg Lego]

The Guess who entity posted thusly:

directory tree. Turns out Enoch pointed me at it, in a directory (msdos) that I would never have thought to look in. Anyway, that pointed me to the author's web site, and I grabbed the latest version (2.0n).

That's a slick little program. Gonna try making some paraboloids.

[Guess who]

That will be difficult, since it's all 2D. I could point to some 3D software, but you still won't get it to leap off the paper. Stick to the 2D and rotate the finished template.

[Chris Friesen]

Generate a sine function in a spreadsheet, plot it on a chart, print it out.

y=h*sine(x)

y: output value h: height of the spline (above and below zero) x: input in degrees

Chris

[Morris Dovey]

| However, the question remains--what if I wanted a curve with a | different amplitude or wavelength? This template idea crossed my | mind, but how to generate such a curve? Can Autocad do it?

This is the easiest part of all. Draw a sinusoid (a sine or cosine curve) with any amplitude or wavelength, then stretch (or squash) to the amplitude and wavelength you want. Copy and paste as many cycles as you want.

-- Morris Dovey DeSoto Solar DeSoto, Iowa USA

[Bugs]

Sine curves don't faintly resemble the conic projections, ellipse and parabola except that they are all curves, which includes an infinite family of exponentials, logarithmic, etc. etc. Since wine bottles are basically cylinders, the family of conic projections will fit them precisely. If you want some air space between the bottle and rack, then almost anything should do. Those interested should open a book on analytical geometry. Bugs

[Leon]

Except that ellipses have curves with more than 1 radius similar to sections of a sine wave.

Which is why I indicated an arc will fit more closely fit or follow the shape of a bottle than an ellipse. An arc is a section of a circle. An ellipse is a circle illustrated in isometric or 3d format.

[Oleg Lego]

The Guess who entity posted thusly:

That was my plan... I only need a few templates to form a framework to be filled. I was going to use the "hanging chain catenary" for it, but this will be easier.

[Guess who]

They are different. You can still as easily plot the catenary though if that's what you want. Nobody will notice the difference [or be too interested.] You'll need the parabola if you need a focal point.

[Oleg Lego]

The Guess who entity posted thusly:

Interesting. I was told that a catenary was a parabola. Of course it was a web page somewhere that told me this, and we all know how absolutely accurate web pages are. I will need a focal point, so thanks for the info.

[Guess who]

The parabola is a conic section. The catenary's a different ball of wax involving exponentials. Have fun looking into it. I'll end it here.

[Morris Dovey]

| The Guess who entity posted thusly: | || On Mon, 20 Feb 2006 12:50:59 -0600, Oleg Lego || wrote: || ||| That was my plan... I only need a few templates to form a ||| framework to be filled. I was going to use the "hanging chain ||| catenary" for it, but this will be easier. || || They are different. You can still as easily plot the catenary || though if that's what you want. Nobody will notice the difference || [or be too interested.] You'll need the parabola if you need a || focal point. | | Interesting. I was told that a catenary was a parabola. Of course it | was a web page somewhere that told me this, and we all know how | absolutely accurate web pages are. I will need a focal point, so | thanks for the info.

They're actually very different critters, as you can see from the "shape" of their defining equations (source: Burington's "Handbook of Mathematical Tables and Formulas") -

Catenary: y = a * (exp(x / a) + exp(-x / a)) / 2

Parabola: 4 * a * (y - k) = (x - h) * (x - h)

For a wine rack, I think I'd want concave circular arcs to support the bottles - with either a horizontal flat or an ornamental convex curve connecting those arcs. A repeating ogee might give an interesting appearance...

-- Morris Dovey DeSoto Solar DeSoto, Iowa USA

[Guess who]

That was my own thought. I was just having a bit of fun. One of the best and most practical approaches is to look at where you "think" you'd like the curve to go, and make a few marks. Then join the dots with the French Curve. If anyone does get carried away with the esoteric, and I've seen some fine woodworking that really was a work of art, they might look here for further inspirationin their "famous curves index":

works just fine.

[Morris Dovey]

| Graphmatica is shareware, but free for those who can't afford it [so | just use it if you can't.] PhotoFiltre , or "The Gimp" are freeware | image editors. OpenOffice is a great free office suite with a | wordprocessor and spreadsheet and much more.

Wow! I downloaded Graphmatica and _really_ like it. Wish I'd had something like this when I was in school...

-- Morris Dovey DeSoto Solar DeSoto, Iowa USA

[Guess who]

Perhaps your kids can use it ..or theirs?

It's mostly math, but anyone doing wood modelling can find a use. A parabolic arch is the best support [to do with the focus], so would make a good support for benches, tables, and so on. CAD will draw the circle and ellipse, but I don't know of one that will draw a parabolic curve. There are always layout methods, which were likely used in the past [e.g. by the Romans] since the computer wasn't available way back then. Layout is still generally the best if not too tedious, and I'm not sure yet on the best way to get a printout to scale for a large project. I'll work on that, or offer something about the layout procedure. ...in time; too busy right now.