I think that my real problem is that I do not know how to find out where the neighbors of a particular vertex are. I do not understand much about cloth simulation algorithms but I wanted to be able to apply a cloth effect onto a mesh. Many algorithms assumed the cloth to be shaped as a flat square, however, I would like the cloth to be anything, whether it is a sphere or some hat. In other words, I just realized that making a grid would probably not be a good idea. What do you think~?