An Introduction to Physics Engines Michael Sundqivst TV10S1M3

 Overview – what is a physics engine?  Collision types  Rigid body dynamics  Soft body dynamics  Fluid dynamics  Views for the future  Summary

What is a physics engine?  Simulates real-world physics  Knows generally about physics but isn’t pre-programmed for any game  Advantages: Saves time Quality of animation  Weaknesses: Processor usage Too big for certain projects Scope

Collision types  Two methods of detecting collisions:  Bounding-box: Two meshes, one for viewing and one for calculating physics (collision geometry) Broad phase collision detection  Finite-element: 3-dimensional volumetric tesselation Used by a solver to model stress

Rigid Body Dynamics  Solid, non-deformable object  Enables rolling physics  Forces that affect movement: Gravity – falling speed Mass – force required to move the object  Examples: rolling balls, solid items  hDCk2rD0Y hDCk2rD0Y

Soft Body Dynamics  Physical simulation of deformable objects  Tries to contain original shape (unlike fluids)  Generally only visually plausible emulations  Uses: destructible materials, plasticity and melting, hair, fur, simulated organs  sMZlBbQ4 sMZlBbQ4

Fluid Dynamics  Interaction of liquids and gases with surfaces defined by boundary conditions  Made of numerous particles, usually acting within a grid  Common uses: liquids, smoke, fire, explosions, gases  wYVLNiOs wYVLNiOs

Views for the future  More processing power = better quality  Even more realistic engines  Growing usage on mobile devices  Visually stunning games