Note: This option can only be used with 256 color modes.
Fractint's images are usually calculated by the "level set" method, producing bands of color corresponding to regions where the calculation gives the same value. When "3D" transformed (see "3D" Images ), most images other than plasma clouds are like terraced landscapes: most of the surface is either horizontal or vertical.
To get the best results with the "illuminated" 3D fill options 5 and 6, there is an alternative approach that yields continuous changes in colors.
Continuous potential is approximated by calculating
potential = log(modulus)/2^iterations
where "modulus" is the orbit value (magnitude of the complex number) when the modulus bailout was exceeded, at the "iterations" iteration. Clear as mud, right?
Fortunately, you don't have to understand all the details. However, there ARE a few points to understand. First, Fractint's criterion for halting a fractal calculation, the "modulus bailout value", is generally set to 4. Continuous potential is inaccurate at such a low value.
The bad news is that the integer math which makes the "mandel" and "julia" types so fast imposes a hard-wired maximum value of 127. You can still make interesting images from those types, though, so don't avoid them. You will see "ridges" in the "hillsides." Some folks like the effect.
The good news is that the other fractal types, particularly the (generally slower) floating point algorithms, have no such limitation. The even better news is that there is a floating-point algorithm for the "mandel" and "julia" types. To force the use of a floating-point algorithm, use Fractint with the "FLOAT=YES" command-line toggle. Only a few fractal types like plasma clouds, the Barnsley IFS type, and "test" are unaffected by this toggle.
The parameters for continuous potential are:
potential=maxcolor[/slope[/modulus[/16bit]]]These parameters are present on the [Y] options screen.
Fractint's visible behavior is unchanged when 16bit is enabled, except that solid guessing and boundary tracing are not used. But when you save an image generated with 16bit continuous potential:
A 16bit (.POT) file can be converted to an ordinary 8 bit GIF by [R]estoring it, changing "16bit" to "no" on the [Y] options screen, and [S]aving.
You might find with 16bit continuous potential that there's a long delay at the start of an image, and disk activity during calculation. Fractint uses its disk-video cache area to store the extra 8 bits per pixel - if there isn't sufficient memory available, the cache will page to disk.
The following commands can be used to recreate the image that Mark Peterson first prototyped for us, and named "MtMand":
TYPE=mandel CORNERS=-0.19920/-0.11/1.0/1.06707 INSIDE=255 MAXITER=255 POTENTIAL=255/2000/1000/16bit PASSES=1 FLOAT=yes
Note that prior to version 15.0, Fractint: