Originally Posted by Kordanor
@JuliusMagnus (and Myrkrel)
I am pretty sure that it's neither of the three options.
First thing to understand is, that there is no random for PCs. Everytime you need a random number you use a function which is generating a number for you with a formular.
Simple example: If I ask my computer for a random number at 12:00 the number would be 100*2=200. If I ask my computer at 12:01 for another random mumber it would be 101*2=202. Of course, the functions are much more complex.
However if you ask your pc for the random number at the exact same time, you get the exact random number in the case I showed. The "Time" would be the "seed" here.
And thats a very simplified version of how a procedural generated world works as far as I know.
So what you have are tons of mudules. And tons of numbers which tell your PC which modules to use. Example:
You are at the starting area. And look south. The first 50 "tiles" (it's a tile based movement system) are "generated". The generation uses a static formular. E.g. Every second tile is grass, every 10th tile is a bush. At tile 40 the program reaches a formular to generate a small town, which will take a hole block of 10x10 squares.
So what you see is "within" a static formular. The formular is pure math. The "seed" for variations is the same on every version of the game. And therefore the "random numbers" aren't really random but the same on every Game.
Meaning the modules you see are handcrafted, their placement in the world is determined by formulars. Everyone will have the same formulars and the same world. These formulars have the capacity of an infinite world. But this infinite world will be generated on your PC. Only the formular was set in development.