This will lead to the water stabilizing quickly to a fixed state, and from there a lower viscosity can be set. It is hard to initiate a body of water in a steady state using particles, so a 'trick' which I used in the simulation was to initiate the particles in a regular pattern, and run the simulation but with the viscosity of the water set really high, causing very high damping. This has to do with the initial conditions set in the simulation. Something that can be observed in particle based water simulation movies is that they often start with a splash.I made this optional since of the flexibility to be able to run on simulation on the Amazon EC2 cloud computing service, that has more power than my macbook laptop.

For flexibility, and debugging help, I added the possibility to visualize the simulation as it was running using OpenGL.The reason for not using any already available commercial or open source software was purely educational so that I could learn more about particle simulations.Īll code for the simulation is available here: Water_Simulation.zip, which includes both a makefile and an xcode-projectĪ c++ program was written to simulate a number of particles using the SPH-method, that is described in Water. My goal was to create a water simulation of a fountain, and to be able to use that data in the ray-tracer PBRT. This is the main idea behind the Level set method. One way of doing it is do describe the surface through an implicit function, which is evolved through time.

When rendering the water, the particle or grid densities has to somehow be converted into a water volume. One well-known water simulation technique is called ' Smooth particle hydrodynamics', or SPH.

The equations can be discretised and evaluated using a number of methods: those who are gridbased, particled based, or a combintation.

The Navier-Stokes equations are used to describe incompressible flow of a fluid. The problem is that when simulating water for rendering, it is not only the movement of the water in a closed container that is interesting, but rather the interface (water surface) between the water and air, that is important to render realistically. Traditionally water has been simulated in the field of computational physics but but in recent years a number of techniques has been proposed to simulate water for special effects. Water simulation has been used in a lot of films over the years, where it has been practically impossible or to expensive to film using real water. Simulating and rendering water Background Project: Rendering a fountain - Vilhelm Hedberg

Flowing fountain program opengl