Ultra Fractal

Ultra Fractal is a piece of fractal-generation software, Copyright of Frederik Slijkerman. It is probably the common of any fractal software today. It exists in both free and for-pay versions.

Free vs. For Pay
Ultra Fractal can be downloaded for free in a 30-day evaluation trial (which, strangely, never expires) or they can buy the full product for €49/$69/£44 for the standard edition, and €89/$129/£79 for the animation edition. The only difference between the free and for-pay versions is that all disk renders are stamped with the words Evaluation Copy. This can be avoided by using other completely free programs such as ChaosPro which can interpret Ultra Fractal formulas and parameter files to create the renders.

Standard vs. Animation
Ultra Fractal comes in two types; Standard, which only renders still frames, and Animation, which can render movies using keyframes. When downloading the free trial, Animation is undeniably the better choice. When buying the full version, you will have to weigh the two options, as Animation costs considerably more. Remember still that other software (like ChaosPro) can also render Animations from Ultra Fractal files, so this feature isn't really necessary.

The Compiler
Ultra Fractal's compiler uses a fairly powerful language. Although it only has direct support for 2D, Escape Time fractals, it's ability to do loops, multidimensional arrays, dynamic arrays, and class libraries all give it the ability to do manual raytracing. It also compiles transformations and coloring algorithims, which together give the user a lot of flexibility.

The Public Library
On the Ultra Fractal website, there is a public library where all formula authors can upload files with their code. Users can download this in Ultra Fractal by going to Options->Update Public Formulas. After a one-time update of the entire database, a weekly update should be sufficient. Anyone can register to be an author and can upload their own formulas.

Fractal Creation
Ultra Fractal has support for layers with transparency and arbitrary precision when zooming. Its gradient editor is bsed on bezier curves with a dynamic array of nodes through color space. Gradients can be saved in .ugr format, a format which is shared with several other programs such as Apophysis.