How should I replicate incise flow from Wilbur in World Machine?

[Delta_Research]

Hi World Machine community!

First, some background/context for this:
Wilbur is another terraforming program that seems to have started development sometime late 90s/early 2000’s, and is still being updated. (latest Feb. 2019)
It works using filters and is a non-node based program, but it’s strong point is incise flow, which can create realistic fractal mountain chains via flowing and subtracting from the terrain, which creates realistic mountain branches.
(Example from a Discord server, someone imported the heightmap from Wilbur.)

I was wondering how I could replicate this only in World Machine, and have any kind of heightmap as a base.

[WFab]

@Delta_Research You can try using “flow restructure” filter in “synthesize” mode. The structure generated is well suited for a drainage basin, when combined with water based erosion etc. It’s all about the right balance.

[Delta_Research]

Incise flow works in a completely different way than flow restructure. I’ve tried using flow restructure but it doesn’t give the results I want and it is very difficult to control.

Incise flow takes in any heightfield, whether it be noise or any other kind of heightmap, and it subtracts from the base heightmap. Flow restrucutre doesn’t do either of these so I’m looking to try and recreate this in WM. I’ve tried expanding flow from an erosion node but it takes way too long to build and the results aren’t always 100% fractal. Expanding and subtracting the tributary mask from a create water device seems to be better but instead of mountains it seems to be better suited for canyons.

I’ll try asking someone who uses Wilbur a lot and try to get some more technical details about how incise flow works in Wilbur.

[Delta_Research]

Update:
The person who uses Wilbur tried fractal mountains in World Machine, they used flow restructure on an extremely noisy terrain to get the fractal, river-like lines for subtracting from the terrain.

Might be able to post TMD file later.

[Stephen]

I’m only passingly familiar with Wilbur, but from a quick read through, Incise Flow does exactly what it says - calculates the flow over the terrain and then uses that as the basis for subtracting from the landscape.

This is actually a pretty simple operation. I suspect that like many things, getting a good result out of it involves a lot of careful artistry. Incidentally, WM’s “Channeled Erosion” option in the erosion device does the same thing and may get you similar looking results. “Fill Basins” in wilbur is roughly analagous to Flow Restructure with the Ridge Carving parameter set to zero.

[Delta_Research]

Update: Here is the TMD file from the person who made fractal mountains in WM.
MountainFractallingWM(1).tmd (266.9 KB)