This program can generate real worlds using nothing but a pseudorandom number generator (commonly known nowadays as an ‘RNG’). The RNG is seeded based on location, and procedural algorithms. The world is almost infinitely big, but uses no actual storage space, and is always the same no matter where you go. A selection of strategically placed internal models and textures gives an appearance of variation between each one.

Rooms are generated, and routes are planned internally using an algorithm I created to ensure you (or bots) can always navigate through the buildings:

It then decides where the ‘best’ place is to put certain objects based on a priority system. In this case, it is considering where to place an object that is best suited for room corners:

You can then explore the building:

Note that this software was written for a previous employer, which means I do not hold the licence, and cannot sell it myself.