3D Real-Time Fluid Simulation

This project contains a 3D grid-based real-time fluid simulation with marker particles in a hybrid pic-flip blend with a particle and a marching cubes fluid visualization.

For more detail take a look at my paper.

Install

The following include and library dependencies need to be included in the project:

• glew - OpenGL Extension Wrangler Library
• glm - OpenGL Mathematics
• SDL - Simple DirectMedia Layer

Usage

In the live-demo you're able to use the following input commands:

Hotkey	Action
e	Zoom In
q	Zoom Out
w	Move Screen Up
s	Move Screen Down
a	Move Screen Left
d	Move Screen Right
space	Pause/Resume Simulation
n	Jump to Next Sim Step
m	De-/Active Gravity Orientation Update
o	+ Rotation Z-Axis
l	- Rotation Z-Axis
right	+ Rotation Y-Axis
left	- Rotation Y-Axis
up	+ Rotation X-Axis
down	- Rotation X-Axis

Furthermore you're able to do an arcball rotation with mouse dragging.

Configurations

You're able to change the following parameters to tweak the simulation behavior in code:

Inside FluidSim3dMain.cpp

Size of the grid-cells in meters

const float GRID_CELL_WIDTH = ...

Simulation time step, which is also the duration each frame is displayed

const float TIME_STEP = ...

Initial geometry file, explaination about the file-format later

const std::string INITIAL_GEOMETRY_FILE_IN = ...

Inside FluidSolver3d.h

Number of particles that will initially spawn in each fluid cell

const int PARTICLES_PER_CELL = ...

Acceleration due to gravitation in m/s^2

const float GRAVITY = ...

Density of the fluid in kg/m^3

const float FLUID_DENSITY = ...

A surface-threshold constant in Pa (N*m) used for interpolation in marching cubes

const float SURFACE_THRESHOLD = ...

Initial Geometry File Format

As mentioned above you're able to use own geometries containing solid-, fluid- or empty grid points. The file has to formated in a special way explained in the following example:

3  //number of solid grid points around the scene as a border
3  //number of empty z-layers (just containing air) in the front of the scene
3  //number of empty z-layers in the back of the scene
16 //number of scene repetitions in z-layers
//next line two dimensional scene that gets repeated f=fluid, a=empty(air), s=solid
aaaaaaaaaaaaaaaaaaa
//... as many lines as you want your grid to be high
fffffffffaaaaaaaaaa 

This example generates a 25x25x25 grid. Please leave out all the comments in your file.

Authors

• Alex Sommer - Initial work

License

This project is licensed under the MIT License.

Acknowledgments

• Using methods found in Robert Bridson's "Fluid Simulation for Computer Graphics"