---
title: "FireSmoke Fuel"
canonical: "https://documentation.chaos.com/space/PHX4MAX/125312149/FireSmoke%20Fuel"
format: markdown
---
This page provides information on the Fuel rollout for a FireSmokeSim object.

## **Overview**

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> Macro (ui-text-box)
> 
> There is no need to use fuel for simple fire, which can be produced with hot air using the default settings of the [Fire Source](https://docs-chaos.atlassian.net/wiki/spaces/PHX4MAX/pages/124528247).
> 
> In case you want to use the Fuel Channel in the Volumetric Settings or the Phoenix Grid Texture, be sure to enable the export of the Fuel Grid Channel from the [Output ](https://docs-chaos.atlassian.net/wiki/spaces/PHX4MAX/pages/125279638)rollout of the Simulator.

> Macro (div)
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> The Fuel rollout controls the simulation of burning. It can be useful for gasoline explosions, or propagating fire, or other special effects that require more control over burning.
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> The process of burning depends on two 'regular' voxel channels (**Fuel**, **Smoke**) and a third, imaginary channel (**Oxygen**).
> 
> - **Oxygen** is calculated as the remaining volume which is not occupied by Fuel and Smoke for a given cell / voxel. For example, if in a certain voxel you have 0.4 Fuel and 0.4 Smoke, the Oxygen would be 0.2 (for a total volume of 1 for the voxel). Burning occurs only in voxels which have **both** Fuel and Oxygen. If a voxel has no Fuel, or is already full of Smoke and Fuel, it won't burn at all.
> - **Fuel** is ignited if the **Temperature** in a given voxel is above the **Ignition Temp**. parameter.
> - When the **Fuel** burns, it releases more **Temperature** based on the **Energy** parameter.
> - When the **Fuel** burns, it releases **Smoke** based on the **Smoke Amount** parameter.
> - When the **Fuel** burns, it adds expanding pressure to the simulation based on the **Propagation** parameter. It can be animated to create explosive effects.
> 
> The burning strength is determined by the smaller of the values of the Fuel and Oxygen channels:
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> - If there is 0.1 Fuel, 0.1 Smoke and 0.8 Oxygen in a voxel, the strength would be 0.1 -  the burning will be weak as there is not enough Fuel to ignite strongly.
> - If there is 0.8 Fuel, 0.1 Smoke and 0.1 Oxygen in a voxel, burning will be weak again because the voxel is overflown with Fuel - there is not enough Oxygen to help the burning.

> Macro (ui-text-box)
> 
> UI Path: ||Select [Fire Smoke Simulator](https://docs-chaos.atlassian.net/wiki/spaces/PHX4MAX/pages/124760253)|| **> Modify panel > Fuel rollout**


## **Parameters**

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