TDH is a props community/forum. It's not a costuming group.
People get this confused so much and it leads to misunderstandings. People post about all sorts of costumes and props in the "Pit". We've had Batman, Predator, Iron Man, 300...all kinds of costumes posted here. Although TDH is primarily for Boba/Jango/Zam/Variant costumes, lets not forget that everyone has always been welcome to post their work here.
501st, RL, JA, and Mercs are costume "groups" who focus on genre specific costumes and trooping in'em. RPF, TDH, CE, and HL are forums that deal with the props that go in to making these costumes.