I love a good rendering challenge actually. XD I take my time taking away the **** thats around the thing I want. <.>
Oh... They didn't look like fractals on Sworns banners... I just feel like those where really clean brushes being used without any modifications to it. Because the fractals I usually see are full of background swirls and the banners I saw with C4Ds had a really clear background and neat/organized brushes.
I like my kitty puns D: Have you tried making some new type of banner or naw or what? wazzup >_>
There is no app for it yet. Its google. Everything is google chrome. The only gimp app it has looks like gimp, but its weird looking that it throws me off. Pixiv is mostly for pictures I guess, but it has basics for art. I made this one in it long ago: