Real-time fluid physics library

The goal is to create a physics library that is specialized on water fluid

dynamics, for real-time simulations.

Why?

Water motion is graphically appealing and it should be possible to use it more in games to enhance the experience.

A physics-based system is needed to enable interaction between fluid and solid meshes.

Milestone 1

Project plan, time planChoose subjects to studyBrief studies of:

Fluid dynamics Fluid buoyancy Smoothed particle hydrodynamics Collision response

Test of a free collision detection library

Fluid dynamics

A mass of fluid can’t resist a shearing force and must deform. Velocity depends on local density in incompressible

fluid.

Motion is described by parcels small enough to neglect rotation. Velocity field representation. Linearization is used to interpolate attributes between

parcels. Bernoulli’s equation, the Navier-Stokes equations.

Fluid buoyancy

Suitable to implement as interaction between fluid and solid meshes.

Archimedes’s principle: F = -p * V * g F must be integrated over the immersed

surface. Problematic for arbitrary surfaces.

Smoothed particle hydrodynamics

Introduced to simulate astrophysics.A kernel function computes interaction

values from particles within a radius.Problems:

Can only solve compressible flow. A surface has to be reconstructed. Not fast enough for real-time in large scale.

Alternative is Eulerian grid.

Collision detection libraries

Avoid developing detection algorithms by using a library.

FreeSOLID OpenGL-like API. Detects overlapping shapes. Approximates collision plane, useful for collision

response. LGPL license.

Collision response

Can be done by applying forces. The objects will interpenetrate.

Compute impulse. Immediately changes velocity and angular velocity. Combine angular velocities using matrices or

quaternions.

Time of collision: Binary search for static collision detection. Time expensive.

Plans

Prototypes for: Collision response Liquid dynamics (using Eulerian grid) Liquid buoyancy

Technical specificationDesign of:

Physics libary Mesh loading and graphics rendering modules.