It took me a while to understand projective dynamics, so here’s my own definition: It’s a graphics technique used to emulate the behavior of deformable objects (hair, clothes, flesh). This object is represented as a mesh of vertices and edges, where every vertex is assigned a position and weight that influences neighboring vertices. The weights are usually determined by the properties of the object being simulated. The main process is using a projection matrix to enforce a series of constraints to the vertices’ motion and helps preserve relative distances (and prevents it from exploding, etc.)