# Cache¶

Reference

Panel

Physics ‣ Fluid ‣ Cache

Type

Domain

The Cache panel is used to Bake the fluid simulation and stores the outcome of a simulation so it does not need to be recalculated.

Baking takes a lot of compute power (hence time). Depending on the scene, it is recommended to allocate enough time for the baking process.

If the mesh has modifiers, the rendering settings are used for exporting the mesh to the fluid solver. Depending on the setting, calculation times and memory use might exponentially increase. For example, when using a moving mesh with Subdivision Surface as an obstacle, it might help to decrease simulation time by switching it off, or to a low subdivision level. When the setup/rig is correct, you can always increase settings to yield a more realistic result.

Note

Fluid simulations use their own cache. All other physics simulations make use of the General Baking operators.

Cache Directory

Directory to store baked simulation files in. Inside this directory each simulation type (i.e. mesh, particles, noise) will have its own directory containing the simulation data.

Type

The type of the cache determines how the cache can be baked.

Modular

In this mode the cache is baked step by step. The bake operators for this type can be found in the other panels within the domain settings. It is possible to cancel and resume a bake process when using this type.

Final

This mode bakes the cache considering all selected settings at once. The bake operator for this type can be found in the cache panel. It is not possible to resume a bake process as only the most important data is being written to drive. Caches will generally be smaller in size though.

Replay

The cache is baked as the simulation is being played in the viewport. It is possible to resume baking when using this type.

Start

Frame on which to start the simulation.

End

Frame on which to stop the simulation.

Note

The simulation is only calculated for positive frames between the Start and End frames of the Cache panel. So if you want a simulation that is longer than the default frame range you have to change the End frame.

Data File Format

File format for the data simulation files. Data simulation files store the information of the most basic grids that are needed for a fluid simulation (e.g. velocity, density).

Uni Cache

Blender’s own caching format with some compression.

Raw Cache

Blender’s own caching format without any compression.

OpenVDB

Advanced and efficient storage method developed by DreamWorks Animation.

All grids are stored in separate .vdb files. Thus every file contains just one simulation field or grid.

Particle File Format Liquids Only

File format for the particle cache files.

Uni Cache

Blender’s own caching format with some compression.

Mesh File Format Liquids Only

File format for the mesh cache files.

Binary Object

Mesh data files with some compression.

Object

Simple, standard data format for mesh data.

Bake All, Free All

This option is only available when using the Final cache type. Bake All will run the simulation considering all parameters from the settings (i.e. it will bake all steps that can be baked individually with the Modular cache type at once).

The progress will be displayed in the status bar. Pressing Esc will abort the simulation.

Once the simulation has been baked, the cache can be deleted by pressing Free All. It is not possible to pause or resume a Bake All process as only the most essential cache files are stored on drive.

Export the simulation as a standalone Mantaflow script when baking the scene (exported on “Bake Data”). Usually, only developers and advanced users who know how to use the Mantaflow GUI will make use of this functionality. Use a Debug Value of 3001 to enable.