Related to agency is the size of the virtual world we can explore. Immersive environments for thousands of years were very small, typically restricted to a single room, building or an open space where a live action role playing game is situated. The reality we live in is a wide open space that covers entire cities, countries, continents, the planet and space above us. The world size has a direct correlation to agency: The larger the world size, the more freedom we have to move and make choices. Anybody who frequently travels alone or with friends or family will recognize the feeling of being in control and part of the world when you visited other countries or cultures.

Since the start of the 21st century truly remarkable progress has been made in virtual world size. Grand Theft Auto III, released in 2001 was one the first truly 3D open world games that enabled players to freely move by foot, car, boat or metro in Libery City which covered 9 square kilometers.

Only ten years later, Minecraft created an open 3D world that is 4,096,000,000 km2 in size, roughly 500 million times as large as the world of Grand Theft Auto.

But the record for the largest virtual world size was set in 2016 by the space exploration game No Man’s Sky created by Hello Games. No Man’s Sky offers a galatic sandbox of 256 huge galaxies and in total 18 Quintillion planets tallying up to 317,000,000,000,000,000,000,000 km2.

The observable universe so far estimated, has 100,000,000,000 galaxies, each with an average of 100,000,000,000 stars in them. So 10,000,000,000,000,000,000,000 stars and as far as we can tell, more than half have planets around them. The diameter of the observable universe is about 46.5 billion light years or 4,40 x 10²³ km and is only a fraction larger than the 3,17 x 10²³ km of No Man’s Sky.

The driving force behind the spectacular exponential growth in world size is a technique called procedural generation. Procedural generation is a method of creating data algorithmically instead of manual. In the early days of computing, procedural generation was used to deal with limited memory and storage space. Elite (1984) was the game that started open worlds using procedural generation. Thanks to Moore’s Law computer processing and memory storage has doubled every two years and procedural generation in No Man’s Sky is used to generate nearly all elements of the game, including solar systems, planets, their ecosystems, flora, fauna and their behavioral patterns, artificial structures, alien factions and their spacecraft.

Rather than procedural generation, some researchers have also used generative adversarial networks (GANs) to generate content. In 2018 researchers at Cornwall University trained a GAN on a thousand human-created levels for DOOM (1993); following training, the neural net prototype was able to design new playable levels on its own.

Many challenges still remain regarding generating interesting, surprising content, triggers and game logic as we saw in the previous section, but if we focus exclusively on world size, we have reached the point in 2016 where virtual worlds are as large as the observable universe today. In the next few years we can expect to see virtual world sizes to be much larger than our observable universe.