Although most curreutresearchworkon gesture interfaces deals with a one-handed gesture, a two-ha&d dyuamic gesture may have the potemial to provide the more stable audefticieut gesture interface over the one-handed. It uot only increases the amouut of iuformatiou valuable for uiiderstdudiuS complex gestures. but also euhauces expressive powers siguiticantly. We are developing an interactive twohanded Sesture iuterfdce, called TGSH (Tn*o-lzwlded Gesrm tm~irum/re~~~ SHell). enabling the users to manipulate a system by iutuitive dyuamic gestures in a 3D virtual euviromneut. Some prelimiuary experimeuts conducted by using eighteen differeutdyuamic gestures show the advautages of using two hands. TGSH is incorporated iuto a 3D geometric modeler. a VR tool developed in our laboratory. to test aud evaluate how the gesture iuterface cau improve the commuuicatiou performance between the users aud the VR applicatiou in a 3D virtual euviroumeut.