-----Original Message----- From: fractint-admin@mailman.xmission.com [mailto:fractint-admin@mailman.xmission.com]On Behalf Of Jim Muth Sent: 04 November 2002 14:40 To: fractint@mailman.xmission.com Cc: philofractal@lists.fractalus.com Subject: [Fractint] FOTD 04-11-02 (FMOD Fantasy [8])
FOTD -- November 04, 2002 (Rating 8)
Fractal visionaries and enthusiasts:
I named today's highly-rated image "FMOD Fantasy". I gave it the name because the scene is an evaporated all-inside one that consists entirely of < fmod > inside fill. Without the fill, the scene would be a total blank.
I do not know exactly how the < fmod > fill works. I assume it measures some distance, but however it works, it works quite well with today's screen-full of trapped points.
<SNIP> "fmod" tests the value of the iterate Z at each iteration. If the magnitude of the Z is less than 'proximity', the point is (provisionally) coloured using colour [0...255] according to the position of |Z| in the line segment [0...proximity] i.e |Z|=0.5*proximity will be coloured 128 (or thereabouts). On each iteration, if |Z|<proximity then the point is recoloured even if |Z| is now bigger than it was on a previous iteration. This goes on until 'maxiter' is reached and the last provisional point colour is then commited to the image. The resulting pattern is typically overlapping (and squashed) circles. The overlap is due to allowing subsequent iterations to set the colour even if they have a bigger |Z| than previous iterations. The general 'contour' pattern occurs as the contours are centered on values of 'c' that cause |Z| to tend towards the origin (0+0i) as they are iterated. values of 'c' that lead |Z| inexorably to the origin (lets denote one 'X') will be at the centre of fmod patterns, and values of 'c' nearby 'X' will cause |Z| to whirl around the origin in orbits of increasing radius as point 'c' moves away from 'X'. This is a bit tricky to explain, but Fractint's "orbit" feature will show it very nicely! Of course, these values of 'c' are bound to be "inside" points as they are being drawn towards the origin - they are never going to escape and fulfil the bailout condition, becoming "outside" points. Hope this makes sense! Jim, lovely image today - a perfect example of 'fmod' in action! Iain Stirling. --- Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.410 / Virus Database: 231 - Release Date: 31/10/2002