Position relative to what?

[jorgeas80]

If an object is at 0 0 0 it is at the center of the world, which has its own cordinate system, commonly refererred to as either world or global cordinates.
At the very least this is how I have understood.

Thanks for your response. Yes, that was what I thought. In my mind, a "world" is basically the map you're playing on. The coordinate system of that world (map) starts at (0, 0, 0). But is it an arbitrary point? Is the centroid of the polygon defining the XZ plane of the map?

I need to know how this coordinate system is created, because I'm going to transform the coordinates of some elements put in the world (the lights) to another coordinate system, defined in the real world (my room).