Sealed arcologies

Sealed arcologies are always surrounded by a spherical or dome-shaped shield that creates and maintains an artificial atmosphere and environment. Arcologies are typically designed to be self-sufficient so as to minimise the amount of traffic coming in or out of the city. Of course, this is meant to be more of a design guideline than an actual principle that is actively enforced. Every city in the empire relies on trade in one form or another, but as long as the city is able to produce enough food, water and electricity to not have to rely on another city/planet to stay alive, then the goals of self-sufficiency has been adequately met as far as the arcology is concerned.

It is extremely difficult and expensive for an arcology to expand its borders. For this reason, city developers tend to prioritise miniaturization over all else. Rather than find new ways to stretch the city's shields, it is far more efficient to make everything smaller so as to be able to fit more things into the arcology. Humans are just about the only thing exempted from this rule: from growing miniature "desktop cows" for fresh milk to the widespread use of individual "sleep coffins", most sealed arcologies are all about making things better, faster and smaller.