Hobby Sculpting Molding

i saw this one time on tv, japanese, most of them, make their own action figures of their favorite animation characters. especially those people called "otakus", i think it's the right term. anyway, they used this kind of clay, I'm not sure if it's called the clay of paris,then they mold the clay, arms , legs, head, after then the whole body of their desired character now comes to form. they would sculpt,carve down to its tiniest details, then paint it with detiled color, and done! they have now thier own action figure.