OpenSayal

Table of Contents

• About
• Gallery
• How to Build
• Configuration

About

OpenSayal is a lightweight fluid simulator that is accelerated using CUDA-enabled Nvidia GPUs. It can simulate incompressible fluids and supports gravity, drag, viscosity, and solids.

Gallery

How to Build

Clone the repository.

git clone https://github.com/gopmur/OpenSayal.git

Download dependencies.

git submodule update --init --recursive

Linux

Build dependencies

• cmake >= 4.0
• ninja or make
• gcc
• cuda

cmake -S . -B build -G Ninja -DCMAKE_CXX_COMPILER=g++ -DCMAKE_C_COMPILER=gcc -DCMAKE_BUILD_TYPE=Release

Run the program.

cmake --build build --config Release

you can change build system by specifying your generator after -G.

./build/OpenSayal

Windows

Build dependencies

• cmake >= 4.0
• Visual Studio
• cuda

Enter Visual Studio Developer PowerShell and run these commands in the root directory of the project.

cmake -S . -B build -DCMAKE_BUILD_TYPE=Release -DCMAKE_CXX_COMPILER=cl -DCMAKE_C_COMPILER=cl -DCMAKE_CUDA_COMPILER=nvcc -DCMAKE_CUDA_HOST_COMPILER=cl -DCMAKE_CUDA_ARCHITECTURES="75;86;90"

cmake --build build --config Release

To run the program, navigate to build/Release, copy OpenSayal.exe to build/lib/sdl/Release, and run OpenSayal.exe there.

Configuration

Put a configuration file named OpenSayal.conf.json in the directory in which you wish to launch you program from. You can either copy the configuration provided below or configure from scratch.

{
 "thread": {
  "cuda": {
   "block_size_x": 64,
   "block_size_y": 1
  }
 },
 "sim": {
  "height": 1080,
  "width": 1920,
  "cell_pixel_size": 1,
  "cell_size": 1,
  "enable_drain": false,
  "enable_pressure": true,
  "enable_smoke": true,
  "projection": {
   "n": 50,
   "o": 1.9
  },
  "enable_interactive": true,
  "wind_tunnel": {
   "pipe_height": 270,
   "smoke_length": 0,
   "speed": 0,
   "smoke": 1
  },
  "physics": {
   "g": -5
  },
  "time": {
   "d_t": 0.05,
   "enable_real_time": false,
   "real_time_multiplier": 1
  },
  "smoke": {
   "enable_decay": false,
   "decay_rate": 0
  },
  "obstacle": {
   "enable": false,
   "center_x": 960,
   "center_y": 540,
   "radius": 36
  }
 },
 "fluid": {
  "density": 1
 },
 "visual": {
  "arrows": {
   "color": {
    "r": 0,
    "g": 0,
    "b": 0,
    "a": 255
   },
   "enable": false,
   "distance": 20,
   "length_multiplier": 0.1,
   "disable_threshold": 0,
   "head_length": 5
  },
  "path_line": {
   "enable": false,
   "length": 20,
   "color": {
    "r": 255,
    "g": 255,
    "b": 255,
    "a": 255
   },
   "distance": 20
  }
 }
}

Every configuration key can be defined in a single line or can be defined in multiple levels. for example the following will do the same thing.

{
  "sim": {
    "time": {
      "d_t": 0.05
    }
  }
}

{
  "sim.time.d_t": 0.05
}

{
  "sim": {
    "time.d_t": 0.05
  }
}

For more information on each setting read here