--- title: "Liquid Input" canonical: "https://documentation.chaos.com/space/PHX4MAX/125085168/Liquid%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 [Liquid Simulator](https://docs-chaos.atlassian.net/wiki/spaces/PHX4MAX/pages/125052235) object|| **> Modify panel > Input rollout** ## **Parameters** --- > 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 **$(same_as_output)**. > **$(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/124763480/Liquid+Output#environmentVariables). > > # 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 (legacy-content) > Macro (ui-text-box) > > The default rendering settings are tuned to Phoenix simulations, and they might not work well for imported 3rd party cache files. > This is why when loading **OpenVDB or Field3D files** generated by other software packages, you are given the option to choose a preset. The presets will change the render settings to reasonable default values. The presets will also modify the orientation of the cache files depending on the coordinate system of the source application (Y-up versus Z-up) by Enabling / Disabling the **Flip Up Axis** option. > You can further edit the parameters in the [Rendering rollout](https://docs-chaos.atlassian.net/wiki/spaces/PHX4MAX/pages/124662515) to achieve the desired appearance of your simulation. > > > > Macro (legacy-content) > Macro (ui-text-box) > > You can suppress showing of the dialogues offering presets using the inDontOfferPresets attribute of the Simulator. Setting inDontOfferPresets to 1, as shown in the image below, will disable the presets pop-up window displayed when a VDB or Field3D cache files are loaded. > > ![image](media://c0354988-62cb-4740-a489-056a1e49e782) > Macro (ui-text-box) > > Clicking the "**...**"** **button will open a menu with the following options: > > > > Macro (legacy-content) > > **Browse** – Opens a dialog for choosing one of several cache file types. Phoenix can import **.f3d* and* *.vdb* files from other fluid simulator software products. See [How to import and render simulations from FumeFX, Houdini and Maya](https://docs-chaos.atlassian.net/wiki/spaces/PHX4MAX/pages/125311346/Tips+and+Tricks#TipsImportCaches). > > - **Phoenix** ****.aur*** > - **Field3D ******.f3d*** > - **OpenVDB ******.vdb*** > - **Krakatoa ******.prt*** > > **Reset to Default** – Resets the cache path to the default value of *$(same_as_output)*. > > **Show File Name...** – Evaluates the full disk path provided to the **Simulation Cache Save Path** parameter. > > **3rd Party Channel Mappings...** – This option is available when a *.f3d* or *.vdb* cache is loaded. It launches the Channel Mappings dialog for mapping 3rd party cache channels. See the [Channel Mappings](https://docs-chaos.atlassian.net/wiki/spaces/PHX3MAX4EDIT/pages/115050295) section below for more information. > > **Help** - Opens this Help page. ### > Macro (anchor) Time Bend Controls --- This section contains playback options you can use for retiming a simulation after it has already finished. Using these, you can speed up, slow down or animate the motion of the simulated sequence. When retiming an existing simulation from this section without re-simulating, additional RAM might be used, and loading a new timeline frame may take longer when the frame must be obtained by creating a new one between two adjacent cache files. We will refer to the process of creating an intermediate frame from two caches as **Blending**. Some of the settings in this section might require specific grid or particle channels to be saved to the cache files during simulation from the [Output ](https://docs-chaos.atlassian.net/wiki/spaces/PHX4MAX/pages/124763480)rollout. > Macro (ui-text-box) > > In order to blend particles, you must enable the export of the Particle ID channel from the [Output](https://docs-chaos.atlassian.net/wiki/spaces/PHX4MAX/pages/124763480) rollout of the simulator. ### > 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 after 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 Liquid surface, or to get smooth motion blur by smoothing the Velocity grid channel. ## **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