# Filter Change

## Overview

The Filter Change distribution makes a selection based on the effect a specified filter has on the terrain. This can be used to for example mask out the area affected by an erosion filter.

## Parameters

<table><thead><tr><th width="199.7999267578125">Properties</th><th>Description</th></tr></thead><tbody><tr><td><strong>Filter</strong></td><td>References a filter to capture. You can simply drag a filter from your biomes filter list into this slot.</td></tr><tr><td><strong>Level Step Strengths</strong></td><td>Allows you to select at which level steps you want to capture the changes made by the filter.</td></tr><tr><td><strong>Normalize Levels</strong></td><td>Normalizes the strengths of all levels to the 0 to 1 range.</td></tr><tr><td><strong>Combine Operation</strong></td><td><p>Applies different operations when capturing the mask. Max results in all points added to the terrain being filtered, while min only takes the lower points.</p><p><br><em>This is not a correct representation for measuring sediment added in erosion, since each step of an erosion simulation erodes and adds sediment to the calculation, which can lead to a heavily eroded piece of terrain with some light sedimentation on top, which would lead to only the large erosion being visible (while there's also sedimentation present).</em></p></td></tr><tr><td><strong>Level Power</strong></td><td>Applies scaling to the different levels to scale their effect on the overall result.</td></tr><tr><td><strong>Scaling</strong></td><td>Increases/Decreases the strength of the effect.</td></tr></tbody></table>

## Results

<div><figure><img src="https://2837684122-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FM6zsxw2jbMYEZbKqEwpa%2Fuploads%2F4L0YDjKbdFaQQe5LQYVT%2Freference_distributions_filterchange_01.webp?alt=media&#x26;token=776a62d6-45d0-4295-9577-a0711c232535" alt=""><figcaption></figcaption></figure> <figure><img src="https://2837684122-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FM6zsxw2jbMYEZbKqEwpa%2Fuploads%2FWFZQgiDuvh4RiRKZyweA%2Freference_distributions_filterchange_02.webp?alt=media&#x26;token=76a2ae65-a088-4239-987e-86f72763ae02" alt=""><figcaption></figcaption></figure></div>


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