a promblem of dragon wings with MAYA ncloth


Hi guys I have been working on a personnal project recently,and really get confused about dragon wings when I try to simulate it using ncloth, because when I do the modeling I make the dragon wings a whole mesh with the body ,so it has tow side ,not a flat plane, and then when it come to simulation, the whole wing become fat like someone pumped some air into it (like the image below), i looked into maya help and get nothing ,any one can help me with that?