---
title: "Advanced Surface Scattering"
canonical: "https://documentation.chaos.com/space/VMAYA/111739280/Advanced%20Surface%20Scattering"
format: markdown
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This page provides information on the advanced options of the Surface Scattering in Maya. 


## **Edge Trimming**

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### Edge Trimming V-Ray Proxy Files

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V-Ray Proxy files are often created in other software, not Maya. This may result in their axes having a different orientation than the native Maya one. Having axes with a different orientation obstructs Chaos Scatter from trimming the instances properly. This is the case for all Chaos Cosmos assets and proxies created in V-Ray for 3ds Max. You need to adjust their axes if you want to scatter such proxy files and use Edge Trimming. To do so:

- Go to the proxy object's attributes, and in the **Basic Parameters** rollout, enable the** Flip Axis** option.
- In the Scatter Object's attributes, go to the **Transformations** rollout > **Rotation **and disable the **Preserve Model Rotation** option.



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### Example: Enable Edge Trimming


Turning on the Edge Trimming function deletes all grass strands that are outside of the Target Object, creating a clean line, imitating that the grass has been professionally cut.



## **Slope Limitation**

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### Example: Slope Limitation Up Axis


The **Local **and **World** Slope Limitations determine the up-vector. The Local option uses the normals of the **Target **object; the World option uses the Y-axis of the scene. In this example, the **Min/Max Angle **is set to 0.0°-45.0°.


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### Example: Min/Max Angle


The Min/Max Angles remove instances based on the angle of the underlying geometry. These options can be used to remove geometry from steep areas as well as shallow areas.



## **Altitude Limitations**

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### Example: Altitude Limitation


Setting the **Max Altitude** to 5000.000 cm (500m) limits the scattered trees to that height.


## Falloff Curve

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