The Subdivides Menu provides commands for selecting the subdivision algorithm to be used as well as the number of subdivisions for the next render operation.
There are two subdivision algorithms available. Each of these is described in greater detail in the section of Theory of Operation in the manual. Basically, Carpenter Subdivides yields very dramatic terrains which are subject to “creasing” artifacts. Miller Subdivides yields more realistic terrains, which have no such “creasing” artifacts, and are therefore the default choice.
Remember that although higher numbers will yield much nicer looking results, they require more RAM and more compute time. It is very expedient to choose a course level of subdivision (4-6 depending upon the speed of your particular Macintosh) in order to “look for” a nice fractal or try a different set of color parameters. Once you’ve found something that looks promising, you can then up the number of subdivisions and kick off a new fractal before you go to bed!
Fractal! runs fine under VM, and in fact, it is reasonably efficient with it. Because of the method used for rendering, there is minimal disk thrashing once the subdivision phase is complete (the subdivision phase typically takes less than 1/2 percent of the entire rendering time when rendering polygons). Expect the subdivision phase to thrash a lot!
