Springs and Spring-Like Things

One of the most useful forces we can create for our engine is a spring force. Although springs have an obvious use in driving games (for simulating the suspension of a car), they come into their own in representing soft, deformable, or non-solid objects of many kinds. Springs and particles alone can produce a whole range of impressive effects, such as ropes, flags, cloth garments, and water ripples. Along with the hard constraints we'll cover in the next chapter, they can represent almost any kind of object.