Hidden Interiors Universe

The Hidden Interiors Universe is the unofficial name of a technical area in Grand Theft Auto: Vice City, Grand Theft Auto: San Andreas, Grand Theft Auto: Liberty City Stories and Grand Theft Auto: Vice City Stories where all the interiors of the game are stored. The function of the Hidden Interiors Universe is to teleport the players from the entrance of the building to the corresponding interior of the building. It is popular with explorers for also housing normally inaccessible interiors, such as interiors only entered during missions, cutscene scenery and cut content.

Mechanics
In Grand Theft Auto: San Andreas, by design, buildings' interiors are not physically placed inside the buildings themselves, but placed somewhere else, high in the sky above the normal game world (around 1000 metres, compared to the 850-metre height limit for aircraft). Whenever a player walks through a door with a yellow ENEX marker, they are teleported to the corresponding interior in the sky, whose coordinates are actually different from the outside world's, although the map is programmed to falsely display the player's location using the outside coordinates, instead of their current ones.

The interiors are grouped into so-called heavens, which is the new map the game loads when an interior is entered. The heaven of the normal world (outside) is referred to as heaven K. Most heavens have multiple interiors stored inside them, allowing the player to explore these if they exit the interior without using the door by using glitches or modifications. Since the game only loads the interiors of the heaven the player entered, the normal world will not be rendered and will be shown mostly empty when the player manages to get out of the interior.

The Hidden Interiors Universe of Grand Theft Auto: Liberty City Stories and Grand Theft Auto: Vice City Stories are not explorable without modifications. The interiors are only loaded by the game when required, such as during cutscenes.

Grand Theft Auto III does not utilize a 'universe system' and has all interiors, such as the Tw@ internet café, stored and loaded inside the normal world (all located in heaven K). There are also some places commonly referred as 'hidden interiors', mainly those used as cutscene scenery. Examples are Joey's Garage, Ghost Town and the rooftop garden on Kenji's Casino. Note that not all of these are factually interiors, but are de facto called hidden interiors by fans due to their inaccessibility and secrecy.

Hidden Interiors Universe in GTA Vice City
Exploration of the universe is much more limited than its Grand Theft Auto: San Andreas counterpart, especially if the game is unmodified. There are far fewer interiors in general and only two heavens with cutscene interiors are accessible without modifying the game, the Apartment 3c heaven and the VCPD HQ heaven, which respectively house The Greasy Chopper and Auntie Poulet's house. The Greasy Chopper is the easiest to view since not the entire building around it is rendered, although both interiors can only be entered by using glitches.

There are also some (mostly unused) interiors to be found hidden in Heaven K, the normal world. The heavens listed under 'Other heavens' only house a single interior, of which the cutscene interior heavens cannot be entered during normal gameplay.

Notable is that, unlike in Grand Theft Auto: San Andreas, most interiors are located on ground level inside the building.

Apartment 3c heaven

 * Apartment 3c
 * The Greasy Chopper

VCPD HQ heaven

 * VCPD HQ
 * Auntie Poulet's house

Heaven K

 * Normal world
 * Cherry Popper Ice Cream Factory office (unused)
 * Howlin' Petes Biker Emporium (unused)
 * Joe's Beds
 * Print Works external building (accessible during Hit the Courier)
 * Vice Point Lockup (used during Cop Land)
 * Viceport Military Warehouse (used if the player fails to steal the tank in Sir, Yes Sir!)

Other heavens
Interiors with an asterisk "*" are inaccessible without modifying the game.
 * Bloodring & Hotring
 * Dirtring
 * El Banco Corrupto Grande and Flange 9000
 * Malibu Club
 * North Point Mall
 * Ocean View Hotel
 * Pole Position Club
 * Vercetti Estate
 * Hotel Harrison*
 * Marco's Bistro*
 * Print Works*
 * V-Rock Recording Studio*
 * Vice City Arena*

Hidden Interiors Universe in GTA San Andreas
Even though the interiors universe is a place itself, it contains many markers that allow the player to enter another place or hidden interior in the state of San Andreas.

In San Andreas, there are 152 hidden interiors located in 19 different heavens.

Heaven A

 * Ganton Gym (start point of all interiors)
 * A diner
 * Well Stacked Pizza
 * Victim
 * El Quebrados Sheriff's Station
 * Madd Dogg's Mansion
 * Crack Den
 * Vank Hoff Hotel
 * Burning Desire House
 * Several Burglary houses

Heaven B

 * Two Brothels
 * Blastin' Fools Records
 * Las Venturas Police Department HQ
 * Las Venturas Planning Department
 * Johnson House
 * B Dup's Apartment
 * Helena Wankstein's Farm
 * Jizzy's Pleasure Domes
 * Tattoo Parlor (Las Venturas)
 * Barbers
 * ProLaps
 * Sex Shop XXX
 * Inside Track
 * The Big Spread Ranch
 * Wheel Arch Angels
 * Several Burglary houses

Heaven C

 * Loco Low Co.
 * Reece's Hair & Facial Studio
 * Caligula's office
 * Katie Zhan's House
 * Ryder's House
 * B Dup's Crack Palace
 * Big Smoke's Crack Palace
 * Safehouse
 * The Pig Pen
 * Several Burglary houses

Heaven D

 * Los Santos Forum
 * Below the Belt Gym
 * Ammu-Nation
 * Burglary house

Heaven E

 * Liberty City
 * Sub Urban
 * An unused warehouse (empty)
 * Ammunation
 * Ten Green Bottles
 * Doherty Garage
 * Caligula's Palace
 * Burglary house
 * Denise Robinson's House
 * Shamal
 * Sweet Johnson's House
 * Sindacco Abattoir
 * Safe House
 * Wu Zi Mu's Apartment
 * The Welcome Pump

Heaven F

 * Burger Shot
 * San Fierro Police Headquarters
 * The Four Dragons Casino
 * The Four Dragons Casino janitor room
 * RC Battle Ground
 * 24-7
 * Motel room

Heaven G

 * ZIP
 * Atrium
 * Lil' Probe'Inn
 * 24-7
 * An unused warehouse (detailed)

Heaven H

 * Alhambra
 * Hemlock Tattoo
 * Jim's Sticky Ring
 * Sherman Dam

Heaven I

 * 24-7
 * Los Santos tattoo parlor

Heaven J

 * Binco
 * Jefferson Motel
 * Corvin Stadium
 * Several Burglary houses

Heaven K

 * Normal world
 * Gasso Gas Station

Heaven L

 * 24-7
 * Palomino Creek Ammunation
 * Several Burglary houses
 * Michelle Cannes' house
 * Dirt Track arena

Heaven M

 * Barber
 * U Get Inn Motel
 * Casino Floor
 * Safe House

Heaven N

 * Zero's RC Shop
 * Los Santos Police Department
 * Cobra Marital Arts
 * Millie Perkins' Home
 * Brothel
 * Secret Valley
 * Ammunation
 * 24-7

Heaven O

 * Safe House
 * Colonel Fuhrberger's house
 * Burglary house

Heaven P

 * Cluckin' Bell
 * Andromada
 * Prickle Pine Safehouse
 * Unused Safehouse
 * Several Burglary houses

Heaven Q

 * Misty's
 * The Four Dragons Casino management room
 * Safe House

Heaven R

 * Wardrobe
 * Los Santos International Airport
 * Francis International Airport
 * Kickstart arena
 * Didier Sachs

Vehicles
Vehicles are only visible if they are specifically made to exist in that universe. Cars are normally invisible in the interior world, however there are a few certain times they are visible. These include:
 * Sentinel - Saint Mark's Bistro
 * Forklift - Breaking the Bank at Caligula's
 * PCJ-600 - during the mission Stowaway
 * Vehicles in a modification garage
 * Vehicles in the stadium events
 * S.W.A.T. in End of The Line

Also note that in the interior world the player cannot spawn a car using cheats. A cheat activated message will appear, but no car will be spawned. It is possible to spawn cars in the interior world using trainers.

Entrances
There are various methods for exiting an interior and being able to explore the interiors universe freely. However, some of these methods require the use of a Jetpack, and this ability may not be available in some interiors, since they may be higher than the height limit for Jetpacks. Therefore, a trainer or mod for an infinite height limit may be required.
 * The easiest method for entering the interiors universe is by going to the Ganton Gym in Los Santos. A small section of the interior's ceiling right above the front door is not solid. The player can stand under this section, equip himself with a Jetpack, and then fly upwards, and he will go through the ceiling and enter the interiors universe. Note that it is essential to kill the four people inside the interior, otherwise the jetpack will not work properly.
 * In the Prickle Pine safehouse in Las Venturas, the ceiling area above the front door and in the main hallway is unsolid. The player must enter the "Jump Higher" cheat, since this particular interior is higher than the game's height limit, rendering the Jetpack useless. The player must jump towards the door, and he will go through the ceiling.
 * Inside one of the maintenance rooms in Caligula's Palace, there is a small open air vent which is used in the mission Breaking The Bank At Caligula's, in which CJ drops grenades through the vent to knock out the security guards in the room below. This vent remains open after this mission. With some difficulty, the player can jump through this vent and appear inside the interiors universe, although this may take many attempts.
 * Inside the Jefferson Motel, there is a skylight inside one of the lobbies that gets shattered by the SWAT team in the mission Reuniting the Families. After this mission, the skylight remains open. The player can jump through the skylight and entering the interiors universe by entering the "Jump Higher" cheat, and then jumping from a potted plant or couch on the other side of the room. If done correctly, CJ will jump through the skylight and land on some solid area on top of the interior.
 * Similarly, if the player looks straight upwards through the same skylight, he may see a save icon floating in mid-air. This save icon actually belongs to the Hashbury Safehouse.
 * Inside the Atrium in Downtown Los Santos, if the player enters it, equips a pistol, and then walks backwards through the door whilst aiming the pistol forwards, he will walk right through the front door and back outside. Although, technically, he will still be in the interiors universe.

General

 * Some interiors have part of the real world rendered outside to simulate a view through the windows. Most interiors in Grand Theft Auto: Vice City utilize this and a famous example in Grand Theft Auto: San Andreas is the Atrium.

GTA Vice City

 * During cutscenes inside Ken's office in Hotel Harrison, the scenery outside does not match with the scenery around the hotel. The cutscenes actually take place south of the underground mall near Collar &amp; Cuffs, possibly meaning that the office was originally supposed to be located there.

GTA San Andreas

 * The interior universe contains many places and interiors, some are used, others are not. One such example is a warehouse, which was never seen in GTA San Andreas. The unused places could have been made for the Beta but ended up unfinished, though.
 * The color of the sky will often change when the player enters yellow markers, for example, entering the large warehouse interior will make the sky appear blue.
 * Many unused, deleted versions of common interiors are found in the interior world, such as a few unused 24/7's, an Ammunation with two floors and a safehouse.
 * Most interiors are in this sky, but some are located inside their actual buildings or under the ground, some of these include The Welcome Pump, Abandoned AC Tower, Sherman Dam Generator Hall, Lil' Probe Inn, Atrium, CJ's garage in Doherty, the Area 69 interior and both cutscene rooms from the Four Dragons Casino.
 * A small section of snowy Liberty City appears in the Saint Mark's Bistro mission in GTA San Andreas. Outside of this mission, the location can be accessed via a non-solid section of the Ganton gym.
 * Dropping down from any interior in the sky will cause the player to fall for about one minute and will eventually hit San Andreas and be wasted if they do not open their parachute (if they had one prior to this) or on the jetpack (if they had one and didn't dismount it). Alternatively, the player may also fall into water.
 * A handful of interiors, such as the Atrium, are special because their respective buildings have windows on them which can be seen through. However, to achieve this, game designers had to place the interior of the building inside the actual building and render the immediate area surrounding the building to a certain radius away from it. For example, in the Atrium, if the player is in the interior and he looks through one of the large windows, he may see the street in front of the interior, along with a few buildings, trees and objects in their respective places. However, the player may notice that he cannot see beyond a certain point. This is because a small section of Los Santos surrounding the Atrium is still rendered around the Atrium, so it can be visible if the player looks outside, for a touch of realism. However, this method was not used for designing all interiors in San Andreas, because they are located in the sky, and as a result, most of the interiors (such as The Johnson House, Burger Shot, etc.) have windows that cannot be seen through.
 * It is currently impossible to reach these interiors in the Mobile version of the game, because cheats cannot be used.
 * After getting Wasted after accessing an interior via abnormal means (i.e. glitches and cheats), the player will respawn at a seemingly random hospital. This is because the interiors are not necessarily located near where their entrances are on the normal map. For example, getting Wasted while inside the Las Venturas City Planning Department will respawn CJ at County General Hospital in Jefferson, since the interior for the planning department is located above the middle of Los Santos.
 * If Carl is not dating Michelle Cannes, she will appear in the Driving School with a random pedestrian. If the player then exits the driving school and waits long enough, the pedestrian will plummet to the ground after around half a minute. This is because interiors lose their collision upon exiting to the normal world, allowing for the pedestrian to fall down to the ground. This normally does not occur with other interiors because they are not located directly above their respective exteriors.
 * Many of the mission-specific interiors (e.g. Big Smoke's Crack Den, The Pleasure Domes, Sindacco Abattoir) can be accessed early in the game without entering the Hidden Interiors Universe via a glitch. However, this glitch is patched in the PC version of the game.
 * The fact that the interiors in the game are located in the sky can easily be confirmed by walking into an interior wearing a parachute. The height bar will go completely full inside an interior.
 * Hemlock Tattoo is inaccessible in the PS2 version of the game since the building shares the same interior as the tattoo shop in Los Santos, making the Hidden Interiors Universe the only way of obtaining those tattoos.