The virtual world itself needs to be defined in a 'world space'. By its nature as a computer simulation, this world is necessarily limited. The computer must put a numeric value on the locations of each point of each object within the world. It is possible to use alternative coordinate systems such as spherical but Cartesian coordinates are the norm for almost all applications. A major limitation on the world space is the type of numbers used for the coordinates.
Some worlds use floating point coordinates.
This allows a very large range of numbers to be specified, with some precision lost on large numbers. Other systems used fixed point coordinates, which provides uniform precision on a more limited range of values. The choice of fixed versus floating point is often based on speed as well as the desire for a uniform coordinate field. One method of dealing with the limitations on the world coordinate space is to divide a virtual world up into multiple worlds and provide a means of transiting between the worlds. This allows fewer objects to be computed both for scripts and for rendering.