--- title: "FireSmoke Input" canonical: "https://documentation.chaos.com/space/PHX4MAX/124662003/FireSmoke%20Input" format: markdown --- ## **Overview** --- The Input rollout determines the path of the input cache files for rendering and previewing, as well as provides controls for playback effects. Note that some playback settings require a fractional input frame, in which case, the frame is blended between the previous and the next one. > Macro (ui-text-box) > > To set up rendering and simulation cache paths manually, see [Changing the Default Phoenix Paths](https://docs-chaos.atlassian.net/wiki/spaces/PHX4MAX/pages/125311346/Tips+and+Tricks#defaultPaths) in the Tips and Tricks page. > Macro (ui-text-box) > > UI Path: ||Select [Fire Smoke Simulator](https://docs-chaos.atlassian.net/wiki/spaces/PHX4MAX/pages/124760253) object|| **> Modify panel > Input rollout** ## **Parameters** --- **Expand** – Opens a floating dialog that contains the selected rollout and automatically folds the command panel rollout. **Re-Center** – Resets the position of the floating rollout. **?** – Opens up the help documents for the Fire/Smoke Input. > Macro (anchor) **Preview & Render Cache Path** |* rendinput* – This is the path to the cache sequence to shown in the preview and rendered. The default is **$(same_as_output)**, meaning the preview and render would show the caches created by the simulation, reading them from the path specified in the [Output rollout](https://docs-chaos.atlassian.net/wiki/spaces/PHX4MAX/pages/125279638). Use the "..." button to the right to select the path or type it manually. Phoenix has some keywords that can be used for more flexibility: > Macro (rw-ui-expands-macro) > > > Macro (rw-expand) > > **$(same_as_output) [nodeName]** – The same path that is set in the [Output rollout](https://docs-chaos.atlassian.net/wiki/spaces/PHX4MAX/pages/125279638) would be used for loading the preview and render caches. When a node name is specified, its output is passed to the current input. > **$(simoutput) **– A synonym for **$(same_as_output)**. > **$(same_as_resimoutput) [nodeName]** – The same path that is set as a [Resimulation Output](https://docs-chaos.atlassian.net/wiki/spaces/PHX4MAX/pages/125312243) would be used for loading the preview and render caches. When a node name is specified, its output is passed to the current input. > **$(resimoutput) **– A synonym for **$(same_as_resimoutput)**. > **$(dir) **– The scene directory. > **$(data_dir)** – The default directory where cache files are written. By default this is $(dir), meaning that the cache files are written next to the scene file, but it can be overridden with a custom directory from the [Phoenix Global Preferences](https://docs-chaos.atlassian.net/wiki/spaces/PHX4MAX/pages/125311186). > **$(scene)** – The scene file name. > **$(handle)** – A unique number of the node. > **$(nodename)** – The name of the node. > **$env(******)** – An environment variable. See [Using Environment Variables](https://docs-chaos.atlassian.net/wiki/spaces/PHX4MAX/pages/125279638/FireSmoke+Output#FireSmokeOutput). > > # signs can be used to specify the cache frame number with at least as many digits as the pound signs. If the number of frame digits is less than the number of pound signs, the number is padded with zeroes to the left. For example: > > > > Macro (iframe) > Macro (rw-ui-expands-macro) > > > Macro (rw-expand) > > > Macro (legacy-content) > Macro (rw-ui-expands-macro) > > > Macro (rw-expand) > > > Macro (legacy-content) ### > Macro (anchor) Grid Channel Smoothing --- > Macro (ui-text-box) > > Grid Smoothing is performed after the cache file is loaded for the current frame, so for large grids it could cause significant lag when changing frames. To prevent this from occurring, switch it off during the design process and re-enable it again before rendering. The controls in this section allow you to smooth the grid channels loaded from cache files for preview and rendering. You can use this to prevent grid artifacts on meshed grid channels such as the Temperature or Smoke, to remove unwanted noise in these channels or to get smooth motion blur by smoothing the Velocity grid channel. > Macro (anchor) ## **Channels Mapping** --- Different applications use different channels and might have different names for them. When loading f3d/vdb files, Phoenix tries to automatically make the conversion to the supported channels. If a channel is not mapped by default, a channel can be manually set from the dropdown menu. It can be accessed from the Cache Path menu when a 3rd party cache is loaded (e.g. *.f3d* or *.vdb* files). All mappings are kept in a single string parameter, accessible by the name *"usrchmap"*. An example mapping string is: *2,density;10,fuel;1,temperature;4,vel.x;5,vel.y;6 ,vel.z;* **The string is composed of pairs of a Phoenix channel index and a string channel name. Phoenix **supports the following channels with the respective indices: **Smoke** - 2 **Temperature** - 1 **Fuel** - 10 **Velocity.x** - 4 **Velocity.y** - 5 **Velocity.z** - 6 **Red** - 7 **Green** - 8 **Blue** - 9 **Viscosity** - 22 **Wavelet Energy** - 14 **Wavelet.u** - 19 **Wavelet.v** - 20 **Wavelet.w** - 21