Domain Object Settings
This page documents settings for the FLIP Fluid Domain object. The simulation domain is the volume where the fluid will be simulated. Fluid cannot exist outside of the domain object. The domain object contains a large number of settings to control the fluid simulation.
Need help with how to create a FLIP Fluid Domain? Take a look at our getting started guide: Creating Your First FLIP Fluids Simulation.
- The domain object should be created from a cuboid shaped object.
- The domain object must be aligned to the Blender X/Y/Z axis' and cannot be rotated.
- The location and scale of the domain object cannot be keyframed or animated.
- The domain object should not contain any modifiers.
- There can only be one domain object in a single Blend file.
The many domain settings are split into collapsible panels, each with their own documentation page. The domain settings can be also viewed in a Tabbed View Mode by enabling the FLIP Fluids Preferences > Tabbed Domain Settings option.
| Simulation Settings | Adjust the domain grid resolution, physical size, frame rate, begin running a fluid simulation, and control other important aspects of baking. |
| Cache Settings | Simulation results are stored in an external location called the "Cache". Set and manage the simulation cache directory in this panel. |
| Display Settings | Adjust how the simulation will be displayed in the viewport and during a render. |
| Surface Settings | Configure mesh generation and data settings for the fluid surface. |
| Particle Settings | Enable and configure fluid particle export and data settings for fluid particles. |
| Whitewater Settings | Enable and configure the whitewater simulation to generate foam, bubbles, spray, and dust particles. |
| Attributes | Generate simulation attributes for the fluid surface and whitewater particles for use in rendering and in Geometry Nodes. The attribute options are not contained in their own panel and are instead located across multiple panels: Surface Settings, Whitewater Settings, and World (Viscosity) Settings. |
| World Settings | Adjust settings related to the world that the fluid lives in as well as properties of the liquid will affect how the fluid behaves within the simulation. |
| Material Settings | Apply Blender materials to the fluid surface and whitewater particles. |
| Advanced Settings | Configure frame substeps, stability, multithreading, performance, optimization settings, and more. |
| Debug Settings | Tools for debugging the domain grid, fluid particles, force fields, and solid obstacles. |
| Stats Settings | View simulation, solving status, timing, and mesh statistics. |
The fluid surface and whitewater meshes are loaded into Blender from the simulation cache and are stored in the FLIPMeshes collection.
| fluid_surface | Triangle meshes representing the fluid surface will be stored in this object. |
| whitewater_foam | Vertex only meshes representing the whitewater foam particles will be stored in this object. |
| whitewater_bubble | Vertex only meshes representing the whitewater bubble particles will be stored in this object. |
| whitewater_spray | Vertex only meshes representing the whitewater spray particles will be stored in this object. |
| whitewater_dust | Vertex only meshes representing the whitewater dust particles will be stored in this object. |
Simulation Mesh Notes
- The whitewater_foam, whitewater_bubble, whitewater_spray, and whitewater_dust objects will only be present if the whitewater simulation feature is enabled. See Domain Whitewater Settings.
- To keep a persistent copy of a loaded frame mesh in your .blend file, you may simply duplicate the loaded mesh (SHIFT+D) to create a separate Blender object. This can be useful for still rendering and for editing a single mesh that won't be reloaded from the simulation cache. Alternatively, you may also export the frame mesh to one of Blender's supported export formats and import back into a Blend file.
- To export an animated simulation for archiving simulations, for exporting to other software, or for sending to a render farm, use Blender's Alembic exporter. See Alembic Export Support.
I am new to the FLIP Fluids addon or fluid simulation, how do I start learning what all of these settings do?
We suggest starting with small simple experiments and not to get too ambitious with your first project. You might have the urge to jump right in and create a huge complex simulation scene, but we suggest scaling back and learning the basics first. Learning a new tool can take a bit of time and jumping into a large project right away can lead to frustration.
We suggest beginning with our getting started guide: Creating Your First FLIP Fluids Simulation.
To learn what a setting does, start by creating a basic scene. Maybe just a ball of fluid dropping, or an inflow pouring into a cube. Read along with the documentation to get an idea of what the parameter does and try only adjusting a single parameter at a time to test how it works. Lowering the resolution to speed up simulation will help you test and compare different parameter values quickly.
In addition to learning through experimentation and documentation, you can check out our Video Tutorial Series and Learning Resources page.
The FLIP Fluids addon contains a lot of different settings to customize how the fluid looks and behaves. Many of the settings are for specific use cases and do not need to be changed for most scenarios and effects. The default values are set up so that they work well with a domain that is roughly the width of four Blender units or more. For many simulation setups, you'll not need to change very many settings outside the default values.
With all of these settings, the UI can be intimidating to a new user of the addon. For beginners, you may enable the Beginner Friendly Mode in the addon preferences. This option will hide all but the most basic and commonly used settings.
In general, all panels except the Display Panel and Material Panel need to be set before baking. The display and material panel all contain settings for viewport display and render setup which can be changed after baking a simulation. The exception is the Debug Panel which contains a mixture of simulation and display settings.
If you are unclear whether a setting must be set before baking, the top of the documentation for each panel will state which parameters must be set before baking.
Ideally, the domain should fit as tightly as possible around the fluid effect that you are trying to achieve. A tight fitting domain maximizes performance.
Why should I make my domain fit more tightly around the effect? The simulator makes calculations over the entire domain/grid volume. If there is a lot of empty space in the domain, this can lead to more calculations and longer simulation times.
A tighter fitting domain can also concentrate the grid resolution. A tighter fitting domain at the same resolution may have smaller voxels. This can help obstacles and other simulation objects show up better on the grid. This will also increase voxel coverage for fluid generating objects, leading to larger amounts of fluid particles and more fluid particles can help produce high quality motion and detail.
Related Topics:
- See the Simulation: Grid Info topic which explains the simulation grid in detail.
- See the first topic in our '10 Tips' article/video to learn more about the simulation grid and how to visualize and debug the grid.
- For more tips on improving simulation performance, see this topic: Scene Troubleshooting: Simulation baking is taking too long to compute!
- Is your fluid never going to reach the top of your domain? Reduce empty space by lowering the domain ceiling.
- Will splashes not reach the sides of your domain? Consider closing in the sides of your domain to reduce the empty space.
- Are you beginning your simulation by dropping fluid from a large height? If the motion of the fall is predictable, consider animating the fall instead and beginning the simulation right before the fluid hits the ground. You may be able to lower the ceiling if you take this route, and you will avoid having to calculate the simulation frames during the fall. Make sure to emit the fluid at a speed downwards as if it were falling.
- Are you simulating a deep ocean or pool of liquid? Think about whether you can get away with simulating a more shallow body of water. Will there be motion deep under the water that will affect the surface? Will you be able to see the bottom of the liquid in the render? If not, consider raising the domain floor and simulating a thinner layer of water. This will also reduce the amount of fluid that needs to be simulated which will speed up baking times.
- Do you need to resize your domain, but don't want to change the voxel size so that the simulation maintains a constant level of detail? Enable the Lock Voxel Size before resizing your domain. When enabled, this option will automatically update the simulation resolution setting so that the voxel size is the same before and after resizing.