Abstract: A method has steps tracking states for objects in a virtual world by software (SW) executed by a processor from a non-transitory physical medium, noting that physics simulation is necessary to determine a change in display for a particular object, noting characteristics of the particular object, selecting from a plurality of modules, a specific physics simulation module optimized for objects having the characteristics of the particular object, and applying the physics simulation module selected to determine display change for the particular object.

Abstract: A method includes steps of opening a link between a player's appliance and a network-connected server providing games, selecting a game to play by the player through an interface provided to the player's appliance by the server, transmitting virtual world data by the server to the player's appliance, along with a version identification, storing the virtual world data and associated version identification in a cache at the player's appliance, playing the game by the player using the player's appliance, and suspending play of the game by the player.

Abstract: A method has steps tracking states for objects in a virtual world by software (SW) executed by a processor from a non-transitory physical medium, noting that physics simulation is necessary to determine a change in display for a particular object, noting characteristics of the particular object, selecting from a plurality of modules, a specific physics simulation module optimized for objects having the characteristics of the particular object, and applying the physics simulation module selected to determine display change for the particular object.

Abstract: A method includes steps of opening a link between a player's appliance and a network-connected server providing games, selecting a game to play by the player through an interface provided to the player's appliance by the server, transmitting virtual world data by the server to the player's appliance, along with a version identification, storing the virtual world data and associated version identification in a cache at the player's appliance, playing the game by the player using the player's appliance, and suspending play of the game by the player.

Abstract: A method for determining forces on a rigid body at least partially immersed in a fluid medium includes steps for (a) dividing the rigid body into a number of cells; (b) calculating buoyancy force on each rigid body cell separately, taking into account properties of the fluid medium, situation as to submersion of each cell, and position of each cell in the rigid body; and (c) integrating the separate buoyancy forces to determine the net force vector and any torque on the rigid body.