Most models of cloth are based on "particles" of mass connected in some manner of mesh.
Because of this, it is not suitable for dynamic models but works very well for stationary or single-frame renders.
The second technique treats cloth like a grid work of particles connected to each other by springs.
Whereas the geometric approach accounted for none of the inherent stretch of a woven material, this physical model accounts for stretch (tension), stiffness, and weight: Now we apply the basic principle of mechanical equilibrium in which all bodies seek lowest energy by differentiating this equation to find the minimum energy.
Rather than springs, the energy interactions of the particles are used to determine the cloth's shape.