Abstract: A process for optimally rendering 3D worlds so that a sufficiently detailed representation of the 3D world is displayed at a frame rate that provides fluidity of motion while maintaining enough context of the world to enable user interaction. A data structure is computed that contains information about how the world is spatially organized. The 3D world is divided into a non-uniform subdivision grid in each of the three dimensions. Each element in the data structure represents one 3D rectangular cell within the spacial subdivision. Each element stores a list of all the objects in the world which occupy any portion of the 3D cell represented by the data element. The subdivision grid and the array are used to determine which portions of the scene are most visually important to the user. An imaginary ray is cast into the subdivision grid from the viewer's perspective along the viewer's line of sight. The first objects rendered are those within the first cell the ray intersects.

Abstract: A system and method for increasing the performance associated with creating simulated 3D worlds from a network. The system and method provides a means for increasing the performance by fetching objects in the order of their importance. A priority scheme is used to determine the fetching, pre-fetching, and caching of URLs. The operations of assigning priorities, making prefetch requests and cache management is driven by data in an asset database table. The database contains information pertaining to each asset within the current scene such as the priority, status, region, type bounds, and retrieval time. The asset database table is updated based on fetching activities, camera position, and the positions of moving assets. A world scene is subdivided into appropriately sized regions when a scene is first downloaded. Asset type origins are defined and moved, based on the position, orientation, and velocity of the camera. Regions are assigned priorities based on their distance from the asset origin.

Abstract: A system, method and computer program product for optimizing a scene graph for optimizing rendering performance. The nodes of an original scene graph are rearranged to minimize a number of state changes while rendering the scene graph. The shapes of the original scene graph are further broken into a plurality of triangular strip sets, which lend to a better rendering performance. The system, method and computer program product also performs transformations on an object in the scene graph and sends the transformed object to a rendering library, which minimizes an amount of data transferred to the rendering library.

Abstract: An apparatus and related method permit viewer navigation and object manipulation within a three-dimensional graphical experience or "virtual world" displayed by a programmable digital computer. The apparatus and method include the display of a series of six buttons. Twenty-four operations are divided among the six buttons, with each button having two pairs of cooperating or complementary operations. Three of the buttons are used to accomplish movement of the viewer in relation to the three-dimensional virtual world, and the other three buttons are used to manipulate selected objects within the virtual world. A mouse cursor is used to select one of the buttons and to activate one of four quadrants associated with the selected button to accomplish the operation associated with the activated quadrant. When a button is selected, it expands from its inactivated or "at rest" state to a larger, activated state. Two adjacent quadrants may be activated to perform two operations concurrently.

Abstract: Conversion of Gregorian calendar dates to dates of a 360-day-year calendar (i.e., a calendar having twelve months of 30 days each), and 360-day-year calendar dates to Gregorian calendar dates, are performed using a single three-column 367-entry conversion table. A search table unit searches the conversion table from the bottom upwards, i.e., a table search index is initialized to a value of 367, and decremented by unity each time a comparison is made and a match is not found. A first field in each row of the conversion table contains Gregorian leap year calendar days-of-the-year, a second field in each row contains Gregorian non-leap year calendar days-of-the-year, and a third field in each row contains 360-day-year calendar days-of-the-year. A graph of Gregorian days-of-the-year versus 360-day-year days-of-the-year has both vertical and horizontal sections.

Abstract: A calendaring system which provides accurate calendaring of all dates between Jan. 01, 0001 and Dec. 31, 9999 by implementation of an extended set of leap-year rules. The system includes a variety of additional useful features including: multiple holiday tables; flexible date formats; free form definition of processing days; full support for fiscal calendaring units; changeable endpoint counting modes; and integrated support for the current date in date calendaring calculations.