2009 is really shaping up to be our year: GAMBIT alum Skeel Lee Keng Siang just won first place in the Ziggyware Fall 2008 XNA Article Contest! Skeel came to us from the National University of Singapore and was the programmer for Tenxion in our 2007 summer program.
His article, "Introduction to Soft Body Physics," begins as follows:
In recent years, there has been a high proliferation in the usage of physics simulations in games. This might be due to the increasing need for realistic movements of the objects to match their realistic renderings. Some of these physics simulations include rigid body simulations where the objects move and rotate but do not change their shapes, and ragdoll physics where the motion of a character can be simulated under force perturbations. There has however not been a lot of soft body physics in games yet, thus it might be worthwhile to start diving into this type of simulation so that you can start implementing some soft bodies for your game.
A soft body is basically an object which changes its overall shape due to external forces acting on it. Some examples that we commonly see include cloth, balloons and jelly. A cloth drapes downwards due to gravitational forces and flutters due to wind forces. Similarly, a balloon enlarges when the internal pressure forces increase, and produces indentations when a child exerts forces on it by squeezing. These kind of natural behaviors are interesting to observe, especially in a game environment where the entertainment value is of high importance.
This tutorial has been written to help you get a quick understanding of some basic theories and implementations behind simulating soft bodies in real time. It is meant for beginners as we will start from the very basics. In an effort to show the usefulness of soft body physics, some of the examples given in this tutorial also illustrate how it can be used as a quick substitution for cases where using rigid body simulation will prove to be much more expensive.
Way to go, Skeel! Congratulations!
(For more of Skeel's work, check out his website at http://www.skeelogy.com.)