LSL Wiki : Coordinate

Coordinate

An SL coordinate is represented by a vector in the form <x,y,z> that indicates a position in a three-dimensional (3D) space defined by 3 linear axes at right (90-degree) angles to each other. Each axis has an associated unit length (meters in SL) and the combination forms a cubic grid.

The origin of a coordinate system is the point where the axes meet, represented by the vector <0,0,0>. In SL the position of any given object or effect can be simultaneously represented by 3 distinct coordinate system types:

Global coordinates represent the component distances in meters from a single point on the grid.
Region coordinates are meters relative to the southwest corner of a given simulator.
Local coordinates give the position of one object or effect with respect to another.

Note: coordinates also apply to textures via UV.

Axis | Vector | UV

Global Coordinates are not relative to the "center" of the grid - if they were, llGetRegionCorner would return <-4, 0, 0> * 256 in Gibson, as that'd be 4 sims left from Da Boom. It's relative to <0, 0, 0>, which is far out in empty space. Da Boom at <1000, 1000, 0> * 256 is simply an arbitrary starting point to allow adding sims in all directions. Huns Valen explained this using the proper terminology on the SL forum somewhere. Huns?

-- EzharFairlight (2004-05-05 12:20:33)