Generating Virtual Worlds

When a user reaches a “VR-world interconnection” point (gate, teleport, etc.), a request is issued to the VR-world generator, which will create the next “portion” of the VRmall to be sent to the user. This request contains the user identity and—possibly—expressly stated user preferences (e.g., “I want a high-quality environment” or “I am interested in velvet textiles”). The VR-world generator additionally retrieves from the user profile database the preferences and information for the specific user (either statically stated or deduced by the VR-mall personalization engine). Afterwards, the VR-world generator accesses the content database to extract the items that will be placed in the new VR-world. The initial list of the items to be placed in the new VR-world is formulated in either of the following two ways: (a) the user selects to visit an “emall department” (e.g., furniture, clothing etc.), in which case the items belonging to the selected department are chosen; or (b) the user requests to see “matching items” to some designated merchandise (items within the shopping cart or some explicitly specified), in which case the items having common properties with the designated merchandise are chosen. The initial item list is sorted in descending order of the sum of scores corresponding to the property-value pairs within each item. The VR-world generator has also an upper limit regarding the number of items that will be placed in a VR-world, and another upper limit pertaining to the download size; if either limit is exceeded, items are removed from the list until the restrictions are met. When the item list has been determined, a proper space element is selected from the content database (one with enough placeholders for the selected items and matching the user preferences), and the items are positioned at the placeholder locations, arranging for “similar” items to be placed in clusters (Lepouras, 2004).
At this point, the VR-world has been fully created and can be sent to the user. Figure 2 presents two screenshots from the VR-mall. The first one illustrates movement along an isle, while in the second screenshot an object has been “grabbed” and is examined.