The Design And Realization Of Virtual Avatar In Virtual Environment

Virtual Reality is a new technology, also a developing technology, a new high technology with good potential. With the development and popularity of VRML, this technology will be further developed. We will see more kinds of imploder tools of VR, these tools will provide more comprehensive support in VR. With the development of computer technology and other subjects, actualize the technology of VR on personal computer become possible.Virtual humans constitute an important part of VR. Virtual humans are being increasingly used in different domains, for example, military affairs, biology engineering, simulating emergency and virtual guide. Virtual human modeling requires to consider aspects belonging to different levels of abstractions. From the point of human-computer intercommunion, the voice and expression are very important, a virtual avatar with voice and expression can carry out clear responses face to users'control orders. In order to increase the help of navigation and the sense of immersion in virtual environment, provide a virtual guide is a good choice. With the guide, it is convenient for users to travel in virtual environment, virtual guide will introduce every sight detailedly with voice and gesture, users can understand their around environment easily, at the same time, virtual guide will make the virtual environment more liveliness and more magnetic. This paper mainly analyse and summarize methods of design a virtual human, and provide a thought of designing an animated virtual guide.Importing virtual guide can take many advantages: find out places where visitors can't arrive; provide additional information about places; avoid other problems, for example, visitors can't feel lonely, virtual environment looks more liveliness; make more like real world. There are more problems need to advert: guaranteeing that the animation will be collision-free with respect to other objects in the world; guaranteeing a smooth animation, with no unnatural character movements; guaranteeing that the animation will be compenetration-free.Making a animated virtual human is a complicated course. First, requires knowledge of different disciplines, such as computational geometry, kinematics, artificial intelligence, computer graphics, and bio-mechanics. Secondly, the complexity of building virtual humans encourages to divide the problem in several sub-problems; this can be done with the five-levels hierarchy. Geometric layer, concerns the definition of the virtual human model and its appearance. Kinematic layer, the virtual human is represented as a set of rigid bodies, called segments, hierarchically organized and connected by joints. Physical layer, the animation is obtained by applying physical laws to different parts of the virtual human body to compute complex animations. Behavioral layer, represents the instinctive behavior of the virtual human. Cognitive layer, binds various stimuli with reasoning processes that allow the virtual human to search for the most suitable action. These five-levels hierarchy are gradually realize human in real word, the realize methods are more and more complicated. At present, most research about virtual human subject are focus on former three layers. H-Anim, the standard for representing humanoids in X3D/VRML worlds, deals only with lower layers of the modeling hierarchy. It does not specify neither how to define the virtual human behavior nor how the different layers can be integrated, it brings developer many difficulty and challenge. Now, it's not easy to create a virtual human with intelligence on cognitive layer.Our work in this paper still belong to original phase in the research of virtual human. Because of the need of the subject, with the completion of fore environment modeling, we start the research of virtual human. About modeling technology. Real-time modeling and dynamic display of complex 3D model are base of VR. Now, this part can be disparted two parts. One is real-time modeling and dynamic display based on geometry model; another is based on picture. Real-time modeling and dynamic display based on geometry model, set up 3D geometry model in computer, generally use polygon to express. Modeling technology based on picture, after take picture use vidicon, obtain planar surface or 3D model of scenery or object automatically, this is VR modeling based on local picture. 3D scanning modeling technology, obtain 3D information of object use huge 3D scanner, its advantage is veracity, but dearly, this is far away from common users. In virtual human modeling, we used the software of 3D MAX. Model virtual human framework with the software, build really virtual human body through process epidermis, and further set up a base of human body modeling accord the H-Anim.In order to carry out human's action based on fore human body modeling, now main methods being used are: key-frame, dynamics, course method and movement capture. Consider the existing experiment devices and the needing of subject, we use the method of key-frame. Before using this method, must describe the connection between bone and joint in human body. We regard joint as point, regard bone as chain, and linking all bones with joint. We use a hiberarchy of human body in abstraction, looks like a tree. Predigesting key nodes in H-Anim about human body, rectifying the key-frames of human's action by hands. In VRML, we actualize virtual human's simple gesture by using JavaScript, also can manage and control these action.Virtual navigation have been aroused more and more attention in academe, become foreland and hotspot in virtual visiting. Presently, there are large number of paper doing research and discuss around this problem, provide some methods. We introduced a new navigation algorithm that avoid some shortages, this algorithm improved Hill Climbing algorithm based on elicitation searching, realize Back_Trace in Hill Climbing, and improve efficiency and reliability in searching optimal path. We can gained high-quality real-time virtual navigation services in virtual world with the algorithm. Virtual human can tread according to the path that produced from the algorithm, thereby, carry out the basic function of virtual guide. We put avatar with animated surface, action and can move automatically into virtual environment, receive a scheming virtual guide or virtual avatar. Finally, we apply the virtual human into virtual campus and virtual showing hall, greatly increasing the intercommunion in virtual environment.In the end, we do a compare in effect between our work and HCI lab's result. From the aspect of human's surface and action, communication of information, virtual navigation, we achieved original aim, implement that use virtual guide leading visitors travel. But there are more work to do, needed to improve, especially on human's face action, we did less work, in the next phase of our work we will do our endeavor on it.