Fluid Simulation: Smoke and Collision

This is a smoke simulation project. We used libigl to render the simulation, and libigl and Eigen to implement the smoke simulation behavior.

This project was built from scratch, forked from the libigl example project.

Demo

Smoke simulation colliding with a ball:

Smoke simulation colliding with a bunny:

Video demonstration and methodology: here

Methodology

Please refer to paper.pdf in this repository for details.

Code Navigation

main.cpp

Runs the smoke simulation
Connects smoke simulation and renderer

visualization.h, visualization.cpp

Wrapper around libigl's simulation viewer

simulation.h

Initializes simulation objects
Manages simulation state variables
Simulates smoke

staggered_grid.h, staggered_grid.cpp

Staggered grid, also known as Marker-and-Cell (MAC) grid.
Discretization of the smoke box space is managed by this data structure
Contains smoke simulation logic; e.g. external forces, pressure projection, advection, etc.

grid.h, grid.cpp

Data structure to hold grids of the staggered grid

Utilities

grid_util.h, grid_util.cpp: helper functions related to grid management
util.h, util.c: other helper functions

Other

constants.h: simulation options and tuning parameters for smoke simulation
point.h, point.cpp: Point object used for Grid objects
list3d.h: 3D list object

Simulation Options

Simulation options can be set in constants.h. After making an edit, make sure to rebuild the project before running it again.

Scenarios

You can customize different scenarios to simulate. Simply set the constants to match the appropriate scenario.

To simulate smoke only:

// external objects
const bool ball = false;
...
const bool bunny = false;

To simulate smoke and ball collision:

// external objects
const bool ball = true;
...
const bool bunny = false;

To simulate smoke and bunny collision:

const bool ball = false;
...
const bool bunny = true;

Performance

If the simulation is too slow, you can reduce the number of particles with the following constant:

// smoke particle count and initial location
const int PARTICLE_COUNT = 10000;

If the simulation is still slow, consider simulating without a bunny object. Also consider using the following setting to display simplified smoke particles.

const bool useParticles = false;

Setup

To clone the repository and its submodules: git clone --recursive https://github.com/MultiW/smoke-simulation.git

The project can be found in: https://github.com/MultiW/smoke-simulation

Dependencies

The only dependencies are stl, eigen, libigl and the dependencies of the igl::opengl::glfw::Viewer.

The cmake build system will attempt to find libigl according to environment variables (e.g., LIBIGL) and searching in common desitinations (e.g., /usr/local/libigl/). If you haven't installed libigl before, we recommend you to clone a copy of libigl right here:

cd libigl-example-project/
git clone https://github.com/libigl/libigl.git

C++11 or higher should be used.

Compile

Note: this project was only tested on Windows 10

Compile this project using the standard cmake routine:

mkdir build
cd build
cmake ..
make

This should find and build the dependencies and create a smoke-simulation.exe binary.

More help with compilation can be found here.

Run

From within the build directory just issue:

./smoke-simulation.exe

A glfw app should launch displaying the simulation.

Collaboration

James Bao and Xin Wang