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->''The door dilated.''
-->-- '''Literature/BeyondThisHorizon''' by Creator/RobertAHeinlein.

This trope refers to a particular sci-fi convention of connoting a "futuristic" setting with doors and hatches that open in unusual, hi-tech ways - doors that dilate like an iris, doors that slide up into the ceiling, doors that ''dissolve'' and rematerialise... Apparently, plain old hinges are extinct in the future.

Outside of this wiki, "Dilating door" is science fiction FanSpeak for the more general trope that we call "CoolButInefficient". This is a reference to Heinlein's advice that you could evoke a futuristic air by casually throwing out details like "the door dilated", as if such things were nothing to really notice.

Subtrope of OurDoorsAreDifferent.
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!!Examples
[[foldercontrol]]

[[folder:AnimeAndManga]]
* The doors on the industrial ship in ''GhostInTheShell: Innocence'' don't make any sense. They consists of four squared panels fixed to two hinges on each side of the doorframe at middle height which are tilted sideways and into the walls. However, it [[RuleOfCool looks quite cool]] when Batou charges through the coridors and every 15 meters one of these opens just a split second before he reaches it.
* Seriously, any SciFi anime (especially pre-2000) has these doors.
[[/folder]]

[[folder:{{Film}}]]
* ''Film/{{Alien}}'': The sections of the air duct system on the starship ''Nostromo'' are separated by dilating hatches.
* PlayedForLaughs in the film of ''Film/{{Barbarella}}'', when Barbarella is wearing (little more than) an animal-skin suit with a long tail and the tail gets trapped in the closing iris.
* The doors on the Death Star in ''Franchise/StarWars''. [[AttackAttackRetreatRetreat "Close the blast doors! Open the blast doors!!"]]
* A bizarre aversion in ''Film/TronLegacy''. The interior of [[spoiler:Flynn's]] house in the Grid has obviously visible hinges and door knobs on all of the doors, such that they wouldn't be out of place in a regular modern house. This, of course, is taking place in the entirely virtual world where CoolButInefficient is king. Even stranger when compared with the AsceticAesthetic design of the rest of the house. In particular, the windows stand out, as they are not made of a solid substance, but instead seem to be SomeKindOfForceField, marking a pretty stark contrast with the doors.
* ''Franchise/StarTrek'':
** In ''Film/StarTrekVITheUndiscoveredCountry'', the ''Enterprise'' halls were designed with various decorative pipes along the ceilings. Problem was they often led to walls with doors that opened upward...
** Amusingly averted in the 2009 reboot of ''Film/StarTrek''. Whereas the Star Trek universe does other things (see below), the Starfleet facility on Delta Vega has a normal exterior door with a panic bar.
* ''Film/DrWhoAndTheDaleks'' has doors that swing into the sides. However, for some reason, that's just not absurd ''enough'', and one of the doors has to open with a ''pressure sensor''. Said sensor is located ''three metres away'', and elevated by about a foot, meaning that it was ''utterly useless'' to the Dalek inhabitants.
[[/folder]]

[[folder:{{Literature}}]]
* Creator/RobertAHeinlein's ''Literature/BeyondThisHorizon'' had a dilating door. There was probably one in ''Literature/{{Friday}}'' as well (it said "the door contracted").
* James White was fond of this in his ''SectorGeneral'' books, even having a speech about what kind of doors there are in the universe. Essentially, doors can open through hinges, slide in or out, open up or down, dilate clockwise or counterclockwise, or create a quantum-physics manipulating field around themselves so that every atom of a person can pass through without hitting the atoms in the door. The person making the speech went on to say that no civilization in the universe was known to be advanced enough to use the last option, and if any were ever to be encountered, [[SufficientlyAdvancedAliens "we will be sure to be very polite."]]
* Ships in ''Literature/{{Animorphs}}'' are 'living metal'.
* Creator/SamuelRDelany's ''Stars in My Pocket Like Grains of Sand'' had "the door deliquesced".
** Parodied in Creator/DavidLangford's [[http://www.ansible.co.uk/writing/drabbles.html first drabble]].
* G. Martynov's ''Starfarers'', a fairly average late day InterplanetaryVoyage novel, features [[SufficientlyAdvancedAliens Sufficiently Advanced]] HumanoidAliens from the [[ScienceMarchesOn planet Phaeton]], who used the disintegrating-and-rematerializing doors in their spaceship.
* OlderThanRadio: In Creator/HGWells' ''Literature/TheSleeperAwakes'' "And then came a strange thing; a long strip of this apparently solid wall rolled up with a snap, hung over the two retreating men and fell again."
* A biotech version from ''Tk'tk'tk'' by David D. Levine. The protagonist is a human salesman on a planet of insectoid aliens, so the squicky reaction one has reading it matches his own.
-->''Walker pressed through the labia of the shop entrance into the heat and noise and stink of the street.''
* Flint of Outworld, a modern caveman in Piers Anthony's ''Tarot'' series, is unimpressed by the inner world's (that have modern tech) dilating door, comparing it to the anus of a defecating dinosaur.
[[/folder]]


[[folder:LiveActionTV]]
* The defensive iris used on the titular gate of ''Series/StargateSG1''. Arguably, this can be justified because the alien gate didn't come with a convenient slot to allow sliding a solid metal door over the event horizon. But then they completely forgot to explain where the iris disappears to when open and where the presumably complex mechanism for operating it is. By ''Series/StargateAtlantis'', they just had a more prop-friendly generally-invisible ForceField that prevented invasion via "Unscheduled Off-World Activation."
* On the original ''[[Series/StarTrekTheOriginalSeries Star Trek]]'' they did everything possible to make the doors interesting; except for having it descend into the floor. That was too expensive.
** The later series increased the budget. Of note are the [[http://memory-alpha.org/wiki/File:Deep_Space_9_airlock.jpg airlock]] [[http://memory-alpha.org/wiki/File:DS9_airlock_interior.jpg doors]] on ''[[Series/StarTrekDeepSpaceNine Deep Space Nine]]'', which look like gears with windows attached to mechanical arms and roll sideways.
*** This design was homaged/copied on ''Series/{{Torchwood}}''.
** On the ''Series/StarTrekTheNextGeneration'' episode "The First Duty", the Academy dorms have doorknobs and hinges.
*** Probably to give the cadets more things to polish.
* ''Series/DoctorWho'' has far, far too many "dilating doors" to list here, but special mention goes to a door in ''Day of the Daleks'' which curls up toward the ceiling in a slow, sinister fashion. ''The Ark in Space'' also features a sliding door that almost takes the Fourth Doctor's arm off. "I'm rather attached to it," he said.
** And, of course, out of universe the classic series TARDIS interior doors qualified--they were supposed to swing open or closed with the push of a button, but (like many of the show's mechanics) rarely functioned correctly. The new series solved this by doing away with the interior doors entirely.
* In ''Series/{{Firefly}}'', on ''Serenity'', the doors to the crew quarters were these elaborate swinging ladder/door combination things. Quite space-efficient, if a bit easy to lock from the wrong side. (And not wheelchair-accessible, although the guest quarters were.)
** Still quite modest for this trope, since all the doors on the ship are opened by hand. The guest quarters have perfectly ordinary, manual sliding doors, again a matter of saving space.
* In ''MysteryScienceTheater3000'', the main characters are compelled through an elaborate series of variously opening doors and into the screening room.
** Well, Cambot is. The audience never sees the other characters during the door sequence; they might be going into the theater through a side door.
** And this might just be a shout out to the opening and ending sequences of Get Smart!
* The doors to personal quarters on the eponymous ''Series/BabylonFive'' open by rotating clockwise. They have been known to fall on cast members. Others open like modern automatic doors, sliding to either side.
** Those doors are actually quite clever, as they're held up by electrical power when open and are closed by the ArtificialGravity produced when the station rotates, with no need for a motor to close them. In the event of a hull breach or life support failure the doors would slam shut on their own without any active safety system required.
[[/folder]]

[[folder:TabletopRPG]]
* In ''{{Traveller}}'', spaceships could have iris (dilating) doors.
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[[folder:WebComics]]
* Subverted in [[http://bobadventures.comicgenesis.com/d/20100116.html this strip]] from ''TheInexplicableAdventuresOfBob,'' when Bob is surprised that alien doors have doorknobs.
* In ''{{Drowtales}}'', the forest-dwelling light elves make use of a magical version of this trope, formed from living, moving wood that spirals open.
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[[folder:WesternAnimation]]
* In one episode of ''WesternAnimation/{{Cyberchase}}'', the kids go to Symmetria to find Ava. The building they encounter has a round door with four holes in it, mounted into a wall with four holes in it. By default, the holes don't align, but every once in a while, the door rotates so that they do align briefly. The trick to getting through is to jump through ''while it's moving''. Nobody gets stuck in it, but it's just asking to happen. Good thing those kids are fairly nimble...
* In ''WesternAnimation/TheLegendOfKorra'', the doors in the police station are a semi-complex pattern of sliding metal slats. Justified, because the main body of the police force are trained [[ExtraOreDinary Metal Benders]], and it's their powers - not mechanisms - that move the doors around. Most of the other doors in the series are traditionally hinged or manually slid doors.
[[/folder]]

[[folder:VideoGames]]
* The doors in {{Descent}} have a variety of opening animations, from just two panels sliding vertically apart, up to to six-part dilating doors, and several in between.
* The ''{{Metroid}}'' series is an excellent example given that pretty much every door needs to be shot to open. Sometimes they require multiple shots. Sometimes they [[LockedDoor need missiles]].
** This is explained in the ''MetroidPrime'' games as being a method of bypassing the door's normal opening mechanism; you're basically lowering a weak shield that's there to keep wildlife (or you in the case of stronger ones) out and the doors are opening automatically (presumably there's a more peaceful manner of opening the doors). The ones that need missiles explicitly have a blast shield (which disappears after being removed the first time) on them for extra security. Some areas of ''VideoGame/SuperMetroid'' have doors which lack the shields and just let your straight through when you approach.
* Although ''VideoGame/GoldenEye1997'' usually does fine with normal sliding doors, the Cavern level features iris doors. And yes, it ''is'' a pain in the ass when the door takes 5 seconds to open while you're fighting a horde of 20 enemies in your back...
* The Vaults from the ''VideoGame/{{Fallout}}'' series are sealed behind doors in the form of enormous steel cogwheels that are rolled along a track by a mechanical arm and then slid shut.
** Parodied in ''VideoGame/{{Fallout 3}}'' in the Mechanist's Lair where the main entrance is a ridiculously complex set of doors that take easily couple of minutes to open entirely. It's also a ShoutOut to ''Series/GetSmart'' and/or ''MysteryScienceTheater3000'', being exactly the same as one of the doors in both those series' famous door sequences.
* ''VideoGame/{{Half-Life|1}}'' - quite a lot of the doors in the Black Mesa Complex do this vertically and horizontally. VideoGame/{{Half-Life 2}} introduces Combine doors, which look like a ton of scrap metal held in place, and each piece individually slides out of the way when the door is opened.
* ''{{Halo}}''. Most Covenant and Forerunner doors are like this. Covenant doors beep before they open though. The Flood-overrun High Charity in the third game has sphincter doors similar to ''Prey''.
* [[{{Squick}} Sphincter]] and other doors from ''VideoGame/{{Prey}}''.
* In the future part of ''VideoGame/DayOfTheTentacle'', the doors open vertically with the original ''Series/{{Star Trek|The Original Series}}'' sound.
* ''VideoGame/KnightsOfTheOldRepublic'' features a variety of oddly opening doors, ranging from the relatively boring two part doors that slide sideways to ridiculously complex systems of interlocking bars that unlatch and slide apart.
* ''QuestForGloryIV'' has a cave with doors that look like [[{{Squick}} giant sphincters]]; however, this is Justified since [[spoiler:the "cave" is actually the fossilized corpse of an EldritchAbomination]].
* Spoofed, of course, in Season 3 of ''[[VideoGame/SamAndMaxFreelancePolice Sam and Max]]'', where the doors on Skun'kape's ship dilate, slide in, and even tilt in -- from opposite sides!
* The doors in ''Franchise/MassEffect'' are made of layers of interlocking parts.
* Doors in ''VideoGame/{{Doom}}'' open upwards, primarily due to limitations of the engine. "Polyobjects" from the version of the engine used in ''VideoGame/{{Hexen}}'' and later source ports can be used to make doors that actually imitate real-world door behavior.
* Despite the HighFantasy-esque setting, doors in ''VideoGame/TheLegendOfZeldaTwilightPrincess'' are surprisingly complicated, mechanically speaking. Many dungeon doors are round, and when pushed in, roll out of the way through some mystery of technology.
* ''StarshipTitanic'''s arboretum has a door that 'grows' open and closed and is made of metal plants.
* ''VideoGame/DeadSpace3'' has doors that fold up, rotate and vanish in the [[spoiler: alien city]].
* In ''PlanetSide 1'''s [[UndergroundLevel Core Combat caverns]], the [[AdvancedAncientAcropolis Ancient Vanu facilities]] all feature large round doors which vanish when approached, then re-materialize. The doors in human facilities such as the bases and towers feature sliding doors which split along the center. Vehicle bay doors in the Tech Plants slide into the ground when a vehicle leaves the vehicle pad.
* Some towns in the Franchise/{{Pokemon}} games, especially from Generation 3 and onwards, have either automatic doors for even civilian houses or, in cases like ''[[VideoGame/PokemonBlackAndWhite Pokémon Black Version's]]'' Opelucid City, thin blue film that fades away into the air (in other words, a ''diluting door'') upon entering, then rematerializes after passing completely through. However, if the setting is old-fashioned, even in more recent games, then the doors are built strictly as hinged boards the way most are in the real world, such as in Sootopolis City (themed on Mykonos, Greece) or White Forest.
* ''Videogame/{{Portal 2}}'':
** The hatch between the Central Control Chamber and the Main Breaker Room is composed of six triangular pieces that can either be inserted and removed straight-on, or rotated into position to provide the standard iris effect. Which method is used appears to be up to the {{AI}} or computer that happens to be in control at the time.
** The doors intended for human use slide into the walls or [=floor/ceiling=] just like modern automatic doors. However, the locking mechanisms consists of pieces of one side which will rotate into the other side in full view of everyone. For the test chamber doors, when they're fully locked, the mechanism completes the Portal 2 logo.
[[/folder]]

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