Shell

A shell building is a buydebug object, that serves as a large fixed-exterior that acts as shelter. In practice, they're used to give a complex yet aesthetical architecture look, that would otherwise be impossible to create. Because of their varying size, some come with a fixed height and are useful for alluding persistent size that is the interior.

Anything that's within a shell (an object, wall segment and flooring) can only be modified with RestrictBuildBuyInBuildings cheat enabled. However, creating a smaller interior and utilizing hidden room markers for outer halls is completely optional. All shell buildings are fixed with their own entrance doors.

Examples of these buildings include the pyramids and the dragon cave exterior in The Sims 3: World Adventures, penthouses and apartments in The Sims 3: Late Night and The Sims 4: City Living respectively, private and big show venues in The Sims 3: Showtime, and futuristic shells in The Sims 3: Into the Future. The Sims Mobile introduces various shell buildings for careers.

The Sims 3: Late Night
Skyscrapers are shell buildings that were shipped with The Sims 3: Late Night. They are "Shell buildings" and only offer one or two floors (such as the basement; some nicer penthouses have a second floor bedroom.) as a playable area for either residential penthouses or community lots, such as bars. More than one rabbit hole can be inside a skyscraper. This is the first time in the series that a skyscraper can be made without the use of cheats, though they were available as neighborhood decorations in The Sims 2: Nightlife and The Sims 2: Apartment Life. Skyscrapers can be placed in build mode, though, as with any rabbit hole, it has to be placed before a family moves in. Although many shells can be obtained from the buydebug catalog, some of them are unroutable due to broken door entrances.

The Sims 4: City Living
Skyscraper shell buildings return in The Sims 4: City Living. They are more often seen as high story apartment buildings and usually have one to four apartments in them, though some of the skyscrapers also have a penthouse on top. Some of the buildings are mostly one-story, but there couple that have two stories. These skyscrapers can not be moved, edited or placed into another world by the player and are only found in San Myshuno.

The Sims Mobile
The Sims Mobile introduces various shell buildings for careers.