Fractal Terrains painting

[feanaaro]

I don't know what the OP was referring to specifically, but the rivers in FT have some problems (at least they had in FT2, I haven't tried FT3) in that they don't precisely follow the terrain configuration, but only roughly so. Sometimes they appear to flow upward (going over small hills etc), and often they end a few pixels before meeting the sea. Sometimes they go in circle, especially when two or more meet.
Moreover, even when they don't have glaring errors, at close zoom levels they are always too straight ant not enough "serpentine".
Overall, the rivers produced by FT may be used as a guide, but you would be better off painting over them and correct any error that there may be. They may work well on their own only in the very lowest levels of zoom (like, worldwide map).

[waldronate]

I don't know what the OP was referring to specifically, but the rivers in FT have some problems (at least they had in FT2, I haven't tried FT3) in that they don't precisely follow the terrain configuration, but only roughly so. Sometimes they appear to flow upward (going over small hills etc), and often they end a few pixels before meeting the sea. Sometimes they go in circle, especially when two or more meet.
Moreover, even when they don't have glaring errors, at close zoom levels they are always too straight ant not enough "serpentine".
Overall, the rivers produced by FT may be used as a guide, but you would be better off painting over them and correct any error that there may be. They may work well on their own only in the very lowest levels of zoom (like, worldwide map).

The rivers in FT3 are a bit better behaved than those in FT2, but they are still computed on a basin-filled version of the terrain computed at a specific resolution (that pause where it's computing a terrain at your requested resolution is where it's taking the abstract FT terrain and making it into something that can be basin-filled and have the raw flow computation done before converting into a vector representation). Because the rivers are computed at a specific resolution, they will be represented as short segments of lines, which may sometimes touch each other on the computation grid during vectorization (these collisions will appear as loops). Because the segments are lines, zooming in far enough will reveal that they are indeed lines. Pointing out that the rivers in FT eventually degenerate into line segments when zoomed in far enough is an awful lot like observing that pixels in a digital image turn into blocks of color when you zoom in on them. The simplest solution for FT's rivers and an image is to generate the original content at a higher resolution. In both cases, there are practical upper limits.

FT was designed for producing whole-world and continental-scale maps to be annotated in CC2 and CC3. Pushing it outside of its intended uses can generate good results, but it can generate awful results as well. Due to the nature of its river generation, it will keep a novice cartographer from committing many of the river placement sins so common around here, at least for the world map.