Interesting thoughts about spirals.

[simone-cervellati]

I found this article online and I had a blast:

http://www.shallowsky.com/blog/science/fibonautilus.html

I was well aware that the fibonacci spiral (or golden spiral) doesn't fit scrolls very well, and guess what: nautilus shells don't like it either. and they do have a spiral that is more similar to the ones we use in the engraving world.

anyway food for thoughts!

Simone

 

[Hora]

Simone,

Thank you for this nice topic and link.

The article is very funny and accurate. The power point is also very nice. Just be careful with what you read! Even if it is copied a million times by vary famous and intelligent people (who didn’t read and check it as well).

For what I have seen so far in the engraving world there are a lot of spirals used to compile the famous scrolls. One of the problems that I have encountered with it is that a "perfect" scroll is very difficult to draw/engrave. If a scroll is pleasing to the eye I am easily tempted to say: It’s perfect, I like it, whatever ratio the scroll is applying to.

Probably the pursuit of the perfect scroll an old mathematical rule to decide if it is perfect would be nice and justifies the effort.

When I searched the web I found all kinds of Golden Ratio’s that where applied to scrolls. Even there is a discussion apparently what a golden ratio is. Or is it just to fit the non-applying nautilus because the shell must be right?

I like the shell. It’s perfect.

 

[DakotaDocMartin]

If a scroll is pleasing to the eye I am easily tempted to say: It’s perfect, I like it, whatever ratio the scroll is applying to.

I agree.

 

[Sam]

I noticed this difference a few years ago, and I'm sure plenty of others have as well. The bottom line is that the Fibonacci spiral is no more or less "correct" than the nautilus spiral, and vice versa. While I love the fascinating discussion of the golden ratio and its many examples in nature, THE most important part of the scroll spiral for designers is a perfect (or as close to perfect as we can make) logarithmic spiral. Whether it's consistent with the golden ratio is not important.

 

[rod]

Putting the posted photo into Adobe Illustrator, and tracing the two scroll discrepancies, shows the shell scroll to have a 75 % decay and the "golden" to be 60% decay, to a pretty close tolerance.

Rod

 

[BES]

http://sphotos-b.ak.fbcdn.net/hphotos-ak-ash4/463983_157489981049539_458619082_o.jpg

 

[monk]

i'm buying a digital pencil that will allow nothing less than a log spiral. if you deviate off course, the pen shocks you !

 

[Hora]

Monk,

I hope you have your webcam on at that moment . . .:biggrin: