Bubbles

This is my personal fluid solver, it is heavily based on the fluid-engine-development book by Doyub Kim, but with GPU support using CUDA - I don't however make any claims of it's performance or quality.

Currently it contain particle-based solvers for the following methods:

• SPH - Smoothed Particle Hydrodynamics
• PCI-SPH - Predict-Corrective SPH

This code was also used for my master's thesis and the code used for boundary routines is located under src/boundaries, and currently supports:

• Color Field [MCG03]
• Asymmetry [HLW+12]
• Sandim's Method [SCN+16, SPd20]
• Dilts [Dill00, HD07]
• Randles-Doring/Marrone - partially [MCLTG10]
• LNM - [OP22]

Building this code is straightforward, simply use the given CMakeLists and make the project. You will need a CUDA capable device (and nvcc installed) and Qhull (for Samdim's Method). If you don't want to build with Qhull, you can set CONVEXHULL_QHULL to OFF when building, it will force Sandim's method to use an internal implementation of the Quick Hull algorithm, however the quality of boundary output will struggle.

mkdir build
cd build
cmake -DCONVEXHULL_QHULL=OFF ..
make -j4

Building Bubbles also builds the binary bbtool that provides utilities for manipulating the output simulation, export/import meshes and SDFs, visualizing simulations, creating rendering files and computing boundaries with different methods. Boundary computation can be performed with the boundary command. Suppose we wish to compute the boundary of a simulation using Sandim's method, simply type:

./bbtool boundary -in <bubbles_output> -method sandim

The following is execution of these boundaries routines (Color Field, Asymmetry and Sandim). Several other helper routines for narrow-band extraction and different methods are also available under src/boundaries. Surface reconstruction can be performed with the surface command, for example: generating a mesh using Zhu-Bridson sdf computation can be done with:

./bbtool surface -in <bubbles_output> -out mesh.ply -outform ply -method zhu

The following image shows the three supported methods sampled at 256³: SPH-based, Zhu-Bridson and the Counting Particles method [QP22].

Bbtool can also be used for generating files that can be used with PBRT-v4 for rendering the particle systems that are exported, and also my own renderer Lit with:

./bbtool pbr -layered -in <bubbles_output> -out geometry.pbrt -renderer pbrt

There are several options in each tool in bbtool so I invite you to type the name of the command and inspect the brief description and flags available.

Images used on the thesis and on this git were rendered with Lit, the file fluid.lit contains the scenes used in the thesis Chapter 3 and images on this git page. Note however that this file uses directives such as:

...
import [ geometry.lit ]
...
geometry[ fluid.obj ]
...

These files must be generated from bubbles output, all simulations can be simply uncommented/commented in the main routine located in bubbles.cpp.