On Fri, 02 Jun 2000 18:26:56 +0200, Tor Olav Kristensen
<tor### [at] hotmailcom> wrote:

>
>Peter Popov wrote:
>> 
>> Cool! Some time age (13 years? Man, does time fly by!) I made a BASIC
>> program for my Apple IIe which produced Moire patterns. Back then I
>> would have never thought of them as of something other than beautiful.
>
>But are there any useful applications for them ?

I have heard of moire pattern analysis being used in vibrational
dynamics but can't say anything for sure.

>> This image reminds me of the good ole days (though yours probably
>> didn't take as long to render, an hour and a half at 280*192 :) ).
>> Very, very soothing.
>
>17 years ago I ordered a Sinclair ZX Spectrum from England.

17 years ago I was probably spending most of my days sitting on my
bottom, building castles from wooden blocks.

>Back then I did some experimenting with Lissajous 
>curves in 2D, and sometimes when plotting those, 
>nice Moire patterns appeared.

Yes, Lissajous... these were the other major fun factor back then. Of
course I did not know what sine and cosine meant but at least I could
tweak and tweak and tweak :)

>> BTW I've found a great way of making tileable moire patterns in
>> PhotoShop so the good ole days are back <g>
>
>How do you do this ?

What is a moire pattern? The overlapping of two similar grids. Make a
grid (for example, create a pattern and fill the canvas with it),
distort it a little bit and mix it with the original. In order to make
the pattern cyclic, the distortion should be cyclic as well. The wave
distortion works well, just make sure that the wavelenghts are
divisible of the image dimensions and the edge pixels wrap around. The
mixing can be done as 'multiply', 'hard light' or virtually any other
mixing type. It gets even better if this is done for the r, g and b
channels separately.


Peter Popov ICQ : 15002700
Personal e-mail : pet### [at] usanet
TAG      e-mail : pet### [at] tagpovrayorg

Post a reply to this message