A multi-user virtual environment system with extensible animations

多人虛擬環境系統結合了虛擬實境與分散式系統，讓網路上的使用者利用各自的虛擬人物(avatar)，在一個擬真的虛擬環境中進行互動。目前此類系統，大多因為受限於其訊息傳輸協定中的格式過於固定，使得虛擬人物動畫播放的設計，皆只能應要求以循序的方式播放，進行一來一往式的互動。為了讓虛擬人物的肢體語言動畫播放更有彈性，本論文以XML標準設計傳輸協定中的訊息結構，包裝動晝的相關資訊，以傳送至使用者端播放。為了說明此包裝方式上的延展性，我設計了三個使虛擬人物動畫播放更有彈性的功能：「虛擬人物動作的同步化」、「彈性的動畫劇本」、「不同動畫型態的整合播放方式」。我選擇以一個開放原始碼的多人虛擬環境系統VNet做為實驗平台，改寫其傳輸協定及動畫模擬等模組，並實作上述延展功能。另外，為了讓我的實驗平台提供更多加值應用的可能，我也設計了一套虛擬使用者的軟體發展介面，及訊息監控介面。最後，透過數個場景與動畫範例，我以實證方式說明此一虛擬環境系統在動畫展示上的延展性。A multi-user virtual environment (MUVE) system integrates the technologies of virtual reality and distributed system to allow Internet users to interact with each other in a realistic virtual environment. Due to the inflexibility of message formats, most existing MUVE systems can only allow their users to display canned avatar animations in a play-on-demand fashion. In this thesis, the XML standard is used to design animation data and message transmission format. In order to illustrate the flexibility of this new protocol, I have designed three extensible functions for avatar animations. These functions include "synchronizing avatars' animations", "flexible animation scripting", and "integrating different animation data formats." An open source MUVE system, called VNet, is used as the basis of my experimental platform, on which I have redesigned its protocol and animation modules. In addition to the three extensions, I have also implemented a software development kit (SDK) for incorporating virtual users and message filtering. Finally, the extensibility of avatar animation is demonstrated in the proposed system through several realistic scenarios