> For the complete documentation index, see [llms.txt](https://docs.world-creator.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.world-creator.com/reference/terrain/effects/fast-flow.md).

# Fast Flow

## Overview

The Fast Flow effect runs a hydraulic particle simulation and creates a mask from it.

## Parameters

<table><thead><tr><th width="199.7999267578125">Properties</th><th>Description</th></tr></thead><tbody><tr><td><strong>Iterations</strong></td><td>The number of iterations the simulation will run for.</td></tr><tr><td><strong>Velocity Threshold</strong></td><td>Particles with a velocity below this value will be eliminated.</td></tr><tr><td><strong>Rain Strength</strong></td><td>The number of rain particles dropped at the beginning of the simulation.</td></tr><tr><td><strong>Smoothness</strong></td><td>Smoothes the resulting mask.</td></tr><tr><td><strong>Flow Cutoff</strong></td><td>Eliminates all particles that fall under a certain amount of water.</td></tr><tr><td><strong>Flow Smoothness</strong></td><td>Blends in softer regions between individual streams.</td></tr></tbody></table>

## Results

<div><figure><img src="/files/VALaber9o9kHoCVZxmRc" alt=""><figcaption></figcaption></figure> <figure><img src="/files/kZfZ2dIbXTdgq9YbUhrG" alt=""><figcaption></figcaption></figure></div>


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