Every object in the game - planets, ships, minefields, etc. - has a number which is used by programs to identify the object. Numbers are allocated separately for each type of object. There are...
- ...up to 500 planets, numbered 1 to 500
- ...up to 999 ships, numbered 1 to 999 (most hosts have a ship limit of 500)
- ...up to 10000 minefields, numbered 1 to 10000 (most hosts have a minefield limit of 500)
- ...up to 1000 UFO objects, numbered 1 to 1000
- ...possibly other objects.
It is important to know about Id numbers of your objects because most actions are performed in Id order. For example, a low-Id ship will rob before a high-Id ship, so the lower one will get the goodies and the high-Id ship will get what's left.
See also: Per-Player Id order
