Modeling Of Virtual Apparatus And Special Effect Processing Of Virtual Scene Based On VRML

With the development of computer and network technology, modern distance education on Internet has become the focus and trend of education technology. At Present,experiment teaching,as an important part in teaching,still can't be carried out well in distance education. Therefore, how to build up a three-dimension virtual laboratory on the network and help students to do experiments on it conveniently is becoming an important subject of research.The paper discusses the modeling of virtual apparatus and special effect processing of virtual scene based on VRML, which include the shape modeling of virtual apparatus, the shadow generating of virtual scene and the dynamic simulation of experimental processes. Firstly, the paper states the characteristics and functions of virtual laboratory, the structural model of virtual laboratory based on WWW and the common methods of building up virtual laboratory. Secondly, the paper discusses the modeling of complex bodies created by using VRML,and proposes the virtual vessel body have preferable facticity by two extrusion shaped which use two Extrusion nodes of VRML to shape inside and outside of vessel respectively. Thirdly, the paper states how to generate the shadows of simple bodies, and how to generate the shadows of complex bodies with the technique, projected geometry onto a flat ground [Blinn88] and generating dynamic shadows [Sandra Sudarsky 2001]. The methods offer a new opinion for the research of realistic display in virtual laboratory. Finally, the paper shows how to realize interaction and animation in remote virtual experiments by VRML, JAVA and EAI, and presents the simulating of sound with the nodes of sound effect in virtual experiments. In addition, the paper, with the technique of generating dynamic objects and particle system, presents the simulating of dynamic phenomena such as precipitate , fog and so on . Thereby, the virtual experimental scene which has the characteristics of interaction , real time, lifelikeness and verisimilitude is created well.