Ridiculously-Fast Construction

A necessity of any Real Time Strategy game in which units or buildings are built on the playing field.

All buildings can be produced and military units trained in a ridiculously short amount of time. Full-fledged headquarters can be built in just minutes, and even elite military units can be trained in under 30 seconds.

Note that this is not explainable simply by claiming that one second of "real time" equals a much longer time in "game time", because other aspects of the game, such as combat, are not sped up by as much. For example, a single construction worker can often build or repair a building faster than a tank can knock it down (very often instantly repairing it at the first moment of contact, at that).

Recent RTS games have danced around this issue by explaining new units as off-map reinforcements, or airborne troops, and/or new structures as "dropped in from orbit". Company of Heroes is somewhat idiosyncratic in this regard, since many of the units in the game, despite being described as "reinforcements" that the player has to "requisition", magically appear next to the barracks where they were requisitioned, in a manner similar to units in traditional RTS games. However, the player is occasionally able to spend resources to call in off-map reinforcements which roll onto the battlefield from off the edge of the map in a more realistic fashion.

For games set in The Future, it's sometimes explained that some kind of new high technology, like Nanomachines or Unobtainium-powered factories, does allow you to churn out a division of tanks or put up base defenses in mere seconds.

Often a prerequisite for Command and Conquer Economy and Construct Additional Pylons. One of the Acceptable Breaks From Reality. Subtrope of Video Game Time.

= Video Game Examples=

Action Adventure

 * Final Fantasy Crystal Chronicles: My Life as a King has Architek, a special kind of magic that not only builds buildings in a few seconds, but also summons residents to them, who will be in the house as soon as it is complete. Handy!

First Person Shooter

 * Partially Justified in Team Fortress 2, as the Engineer's complicated structures are pre-built, and just need to be unpacked. Why they can be unpacked faster by hitting them with a wrench is not explained. A huge Lampshade is (repeatedly) hung on this in the sentry's operating manual with the Uhlman Build-Matic Wrench and lines like "Adjust top bolt located at rear of sentry (swing wrench downwards in a hammering motion)..."
 * Red Faction Armageddon gives you an arm-based nanomachine repair device that can rebuild anything surrounding you in seconds; since odds are good you'll blow up a bridge or staircase you may need later, this is vital.

Four X

 * The Civilization games, while not Real Time Strategy games, still include a form of this trope in that there is a severe mismatch between construction speeds and unit movement speeds. While rates of civilization advance and technology acquisition are relatively close to reality (or at least would be if the Aztecs were launching spaceships in 500BC in real life), it can take several dozen years for a military unit to move from one city to the next one over.
 * In Galactic Civilizations, you can construct almost anything in a week provided you have enough money. Ships large enough to need a Reinforce Field to hold them together. Major monuments. Heavy-duty factories. Usually with options of three different hire purchase plans. You just email them the schematics and they slap it together in a few days.

MMORPGs

 * Lampshaded in World of Warcraft by the ingenious goblin invention "Town-in-a-Box" used in the goblin starting area, which houses several buildings as well as living goblins, who afterwards complain of it being dark and uncomfortable to be stuffed into a hundreth of your size.
 * The MMO Planet Side also uses the Nanoconstruction explanation. Additionally, vehicles that you aren't using any more can be set to disassemble themselves and disappear, and characters with Engineering certifications can carry Nanorepair devices to "heal" machines, and multipurpose "mines" which can be transformed into turrets, mines and others things as needed. Refuelling the main nanotank at each base is part of the game, so that you don't run out of juice in the middle of a battle.
 * The online browser game Ikariam, while construction is much faster than is realistically possible, even the lower level buildings take at least six minutes and the higher level upgrades take hours or even days in some cases. Fortunately all units involved in an attack have double their normal upkeep and it takes a minimum of 20 minutes to transport units to another island, or players wouldn't be able to get any building done.
 * All houses in Kingdom of Loathing get instant erection; no one pitches a tent like an adventurer. A cottage is made simply by slapping anti-cheese into a bowl of cottage cheese (where does the bowl go?). Just add water to the Instant House. Even pyramids, castles and fortresses can be built without spending a turn, not to mention the other, obviously absurd abodes.
 * Dynasty Warriors Online. If you break every single tower in a base, and them capture it, it will have fully built towers full of your troops. They work fast. Also, anything added to your house is instantly there when you get back.

Real Time Strategy

 * In the Cossacks and successor American Conquest series of games, buildings can be constructed (the traditional way of workers hammering at the ground) and units trained extremely rapidly - in some cases literally in a matter of seconds. This is particularly evident in the late game as there are various upgrades in all of the games that greatly reduce build and training times. The effect is also especially pronounced on higher end computers.
 * In Total Annihilation, buildings are built using nanobots. Oddly enough, the game's opening cinematic seems to suggest that the build time in the game is actually slowed down. Justified, in that the whole game offers a logical reason why construction is so fast--namely, the whole concept of war is centered around the capacity of a single unit to make up an army from nothing in a matter of minutes. And they can do it because they have at their disposal the nanotechnological advancements of, approximately, a very very long time.
 * Similarly, in the fantasy-themed Sacrifice, buildings and units are not constructed at all, but summoned/created out of thin air by magic -- literally, A Wizard Did It.
 * The Command and Conquer series made its overcoming of this trope an integral part of the story. Tiberium is the element that allows for 'micro-manufacturing' of all those buildings within about 5 seconds or so, which is why GDI and NOD fight over it so much. The official strategy guide for the original Command and Conquer not only explains how Tiberium enables quick, automatic building construction, but even goes into how your troops and tanks never run out of ordnance, due to a Tiberium reinforced supply of micro-manufactured warheads. They even go into a long spiel on how Engineers can capture enemy buildings so fast -- they're trained so well in the use of shaped charges that they could walk straight through a bank vault without changing pace. Further, much of their training is conducted completely blind, and off-color jokes abound about how quickly they can accomplish certain operations in the dark. In the case of NOD, the majority of all vehicles are also bought and flown in via airstrip, eliminating the construction aspect of the necessity to explain why they materialize so quickly, but not how deliveries are so rapid and constantly successful.
 * Partially explained in Starcraft and, to a lesser extent, Warcraft III:
 * In Starcraft, the Protoss teleport buildings and units to the base instead of actually constructing and training them, and the Zerg, whose technology is all organic, simply have their drones and larvae mutate into buildings and units, respectively. In addition, it is plausible that Terran SCVs, possessing future technology, can construct buildings in no time, and humans are taken out of cryogenic storage. Terran buildings also seems to contain only the bare minimum of everything. Thus, they do not take long to create.
 * In the Starcraft II Terran Campaign, you can obtain an upgrade that allows you to drop pre-built Supply Depots directly from the Hyperion in orbit onto the battlefield, which can save you a lot of time.
 * In Warcraft III, only the orcs and humans use workers to build structures in the traditional sense. The undead instead summon them, and the night elves grow them like plants, even though only some of the buildings are sentient trees, and others are obviously artificial in nature. The game makes no effort to explain the ridiculously fast training for any of the four races, but in the single-player campaign, it is implied that all the units already exist and are fully trained, and the buildings only serve to bring them into action. In some cutscenes, as examples of Gameplay and Story Segregation, we see units training outdoors "for real".
 * Battlezone 1998 has "bio-metal", an insanely useful and multipurpose recyclable living metal that can be reformed and shaped innumerable times with the application of energy. It's Lost Technology, left behind by Ancient Astronauts -- who seem to have inspired the Greek gods -- that were subsequently slain when some of their creations Turned Against Their Masters. Chasing after bio-metal, as with the Tiberium in Command and Conquer, is the central plot driver of the game.
 * Warhammer 40k: Dawn of War justifies this nicely, at least with Imperial forces. Prefabricated buildings are dropped from orbit and then assembled by servitors. Units are requisitioned, and are shuttled in from orbit via pods or dropships. Eldar grow an Unobtainium material using "psychic singing" for their buildings and use teleportation for their transport. Orks construct their buildings from a pile of materials dropped by a flyer, the results being rather slapdash. Chaos summons in its buildings and units via the Warp. Necron buildings are assumed to have been constructed long ago and stored in underground tombs, and then teleported onto the battlefield as needed. The fact that many of the soldiers are veterans with a history of combat stretching back years, decades, or in some cases even centuries or millennia, rather than new recruits (with those units supposed to be being among the game's weakest), also helps suspend disbelief in so far as the setting's premises are accepted.
 * Supreme Commander gets around this by making nano-assembler technology be an integral part of the game setting, to the point that the only resources the player needs to worry about are raw Mass and Energy. Units being constructed are even showed being molecularly assembled as they are built. All units, except for the Commander himself, are unmanned robots, which gets around the problem of having to staff and crew all those combat units.
 * Homeworld and its sequels get around this by also having molecular assembly technology incorporated into the setting. In addition, the crews of the combat vessels are assumed to be colonists from the Mothership that are awakened from cryo-sleep. As there are 600,000 of them, it is unlikely that the player will ever build so many units as to begin stretching disbelief in this regard. In Homeworld 2, the largest production-capable ship, the Shipyard, even explicitly described to be "so massive it needs to be hyperspaced into combat". This also necessitates said hyperspace technology module to be built first (and, in the Vaygr's part, manually researched first). Here, however, even the largest of units show up from somewhere as opposed to magically appear beside the ship, as every production capable unit has an "entry" and "exit" point for ships that can be produced to be deployed. This adds a very breathtaking moments (and also annoying to some extent) when a battlecruiser is finished and is clearing the production bay before it is sent on its order.
 * World in Conflict explains this by having all of the available units as off-map reinforcements. Whenever the commander needs more units, they are simply airdropped directly into the combat zone. Where exactly all these reinforcements (and the planes that are dropping them) are coming from isn't quite explained, but there are some points during missions where you're allowed to deploy a certain number of special units, with the reasoning that they're extra equipment being flown in from nearby depots and bases. This trope is also Lampshaded during one of the missions, where the Americans must take back Ellis Island from Russian Spetsnaz commandos. The Americans are at first confused as to how the hell the Spetsnaz have so many vehicles and equipment, and then quickly deduce that the American garrison on Ellis Island was horribly oversupplied.
 * Played hilariously straight in Netstorm, where much of the game depends on your ability to lay down bridges faster than your opponent in a manner similar to Pipe Dream. Of course, it only gets better when you realise that the entirety of your army consists of static buildings that take the form of cannons. The entire game is based on building your cannons in more advantageous locations than your opponent, and more quickly.
 * Act of War: Direct Action does not have you build tanks and other machinery at your base; rather, you build a landing pad, and your bought tanks are brought in as helicopter baggage. Of course, no explanation is given as to why your tank arrives within seconds of you ordering it. This makes one wonder if it wouldn't be simpler to find a flat piece of land near the enemy base and just fly ten or so of your tanks there.
 * Star Wars: Empire at War has a slightly different, but still pretty absurd, take on this one. Units can be produced only in the strategic galactic map, and take much longer periods of time to produce. And can be dropped into the battle in limited numbers. This would be a justifiable subversion if it weren't for the fact that you can build the Death Star from scratch in less then a month, (game time), and most units in less then a day.
 * Hostile Waters: Antaeus Rising explains this with nanotechnology. The 'base' in the game, the adaptive cruiser Antaeus, is equipped with "Creation Engines" which contain trillions of nano scale assembler robots capable of creating new vehicles from blueprints stored in the carrier in just seconds. The only resource required is 'metal' obtained by scavenger units using disassembler beams to reclaim various wreckage from the battlefield. The disassembling process does take time, presumably due to the lesser numbers of nanobots involved.
 * In LEGO Rock Raiders, once the Raiders have paid the necessary price of energy crystals and ore, already-completed buildings are teleported down from the orbiting LMS Explorer rather than being constructed on-site. Other construction efforts such as assembling Power Paths or repairing erosion still take two seconds at most, though. Additionally, training is still incredibly quick, for instance taking just three seconds to be trained as an explosives expert!
 * Averted, along with many other RTS tropes, in the many historical RTS games by Paradox, such as the Europa Universalis and Hearts of Iron series. These actually feature realistic building and training times, so even though a game takes place over many years, you still really have to plan ahead to make good use of them. Hearts of Iron is an especially interesting example, as construction times vary wildly depending on what you're building. Replacing a militia unit takes about a month. What's that? The USS Enterprise was sunk? You're gonna have to make do without for a while, it takes almost two years to build a new aircraft carrier. It also varies depending on what else you've been building - order a run of multiple destroyers or divisions and each unit past the first will be produced slightly faster than the previous one as the factories already have the necessary tooling set up and experience in place.
 * End War justifies this by having reinforcements come in from off-map as well, flown in via transport chopper.
 * In the game Utopia (an old Amiga game, basically Sim City In Space!), buildings first appear as scaffoldings before they're completed. Curiously, this happens for landing pads too, even though they're just paved squares...
 * Justified in Halo Wars as similarly to Dawn of War buildings, units, and almost all of your resources are brought down from your ship in orbit, UNSC supply pads periodically show ships landing and off-loading supplies and the construction cinematic for a new base depicts two drop ships dropping the two halves of the base which are then welded together.
 * In Majesty, it's a good idea to recruit gnomes. They can build things freakishly faster than the peasants and dwarves. Get a group of 9 gnomes, all your buildings will be complete before you can type the "restoration" cheat.
 * Universe At War: Earth Assault: the Hierarchy actually has construction that seems to take longer then it should. Their buildings are constructed by their orbiting ships, all their builder units do is create unnecessarily elaborate circles to be scanned and read like bar codes. As for units, most of them units are teleported by their Humongous Mecha.
 * Rise of Legends plays it straight, but it might be explainable for the Cuotl (who look like they're just teleporting their units and buildings onto the map) and the Alin (who are masters of magic, and this is clearly shown.) No explanation for the Vinci, however.
 * Played straight in Age of Mythology, but can be taken Up to Eleven with a certain Cheat Code. This cheat code will allow you to train units as fast as you can mash the mouse button or shortcut key. A Wonder, the biggest building in the game, with 9999 "health", can be built in about 8 seconds. It usually takes 8 minutes... with 12 or 13 villagers working on it non-stop.
 * Played straight in the Achron alpha. Buildings are constructed ridiculously fast, even for an RTS. However, this could be explained by the game being in its alpha stage: there's a good chance that it'll slow down to standard RTS speeds by the time the finished product rolls out.
 * Earth 2150:
 * The first game plays this straight with the ED (builds a scaffold then the building's pieces emerge from it) and the UCS (a metallic shell covers the site and recedes when the building is complete). The LC averts this with buildings being lowered from an orbital assembly.
 * The sequel mixes it up a bit: the ED main building is lowered from orbit then it builds the rest around itself; the UCS still plays it straight. The protagonists even use UCS forces in the third campaign especially because they can drop a few construction units disguised as asteroids onto the planet then build their forces on-site and take their objective without getting blown out of the sky by orbital defenses. And since the UCS forces are purely robotic... Supreme Commander comes to mind.
 * The Warlords Battlecry series plays this straight. A eagle/pegasus/dragon nest (mostly made out of solid rock) can be built in less than 30 seconds, and takes about as much time as the construction of a first-level base (which often comprises multiple towers and structures housed around a single building). Building upgrades take roughly the same amount of time, and can comprise multiple building and/or feature additions.
 * SPAZ has no explained excuse for how INCREDIBLY fast ships are deconstructed, constructed, and teleported in. Huge repair projects are completed in a span of seconds.

Simulation Game

 * Animal Crossing mostly runs in real time based on the system's clock. But when another villager wants to move in, her house just appears overnight.
 * In the Sim City games, most buildings like power plants appear instantly. Zoning works differently; you simply designate an area and someone else builds there. Also, time rolls by faster, so...
 * Averted in some of the Harvest Moon games, where construction of new facilties on your farm take at least two days to complete, given the right amount of materials and gold. Played straight, however, in Island of Happiness, where the island's lone carpenter, Gannon, can put together anything overnight once you give him enough money to work with. This seems to suggest that he's really good at his job, or that he Must Have Lots of Free Time.
 * Rune Factory 3, in which all objects that you order to be built are in your house instantly, even the forge and the monster barn.
 * Pre-saved Rollercoaster Tycoon rides can appear in an instant in the player's park. In real-life roller coasters are designed on computers and pre-fabricated off-site so it's not too far from the truth as far as construction goes. Perhaps the biggest difference is the amount of testing and quality assurance needed before the public can have a ride. The game simply requires a single test run.
 * Present in every game of the City Building Series.

Tower Defense

 * Towers in Defense Grid the Awakening come pre-built, as they rise out of preplaced hatches then unpack their weapons. Upgrading towers takes a little longer, since the weapon usually needs to be repacked to fit back through the hatch, but the new tower pops up as soon as the old one is through. Hell, the hatch doesn't even close for this.
 * Plants in Plants vs. Zombies tend to grow ridiculously fast from what is implied to be a packet of seeds.
 * In Orcs Must Die, the Apprentice can instantly summon traps, and guardians only need the time is takes to stand up to be ready for battle.
 * Construction in Gemcraft is instantaneous (it is, after all, magic). Moving gems into them, however, takes time. This evokes imagery of your wizard running up tower staircases carrying huge gems.

Turn Based Strategy

 * Every building in the Heroes of Might and Magic is built instantly, ready for use from the moment it pops into existence. Whether you build a marketplace or an entire mountainside to put those dragon caves in, the only limitation is that you can only build in each city once every day (turn).
 * Game Boy Wars 3 has an Engineer unit with this trait.
 * Justified in Sid Meiers Alpha Centauri;a cutscene shows the wreckage of a battlefield being transformed into a brand-new hovertank in seconds by industrial nanopaste.
 * In Makai Kingdom, you deploy buildings by, apparently, dropping them from high above, with no ill effects other than comically flattening out before resuming normal shape. (The exact same thing happens when you drop in soldiers.) Buildings are actually prepared beforehand in Lord Zetta's home area, and wished into existence, so no actual manufacturing takes place.

Wide Open Sandbox

 * Averted in X3 Reunion and the sequels. If you decide to build a capital ship instead of just buying it from a shipyard, you need to first reverse engineer the ship to learn the blueprints or buy blueprints (lots of money), build absurd amounts of resources, and then you need wait twenty hours in real time as your Player Headquarters builds the ship. Fighter ships take anywhere from 3 minutes to 3 hours to build depending on what class it is (i.e. a scout is quick to build while a heavy fighter takes over an hour); the reverse engineering and build time takes longer the larger and more advanced the ship is. The game thankfully has a device that speeds up time 10x. However, buying capital ships (or anything, for that matter) results in the ship spontaneously being generated from nowhere with no build time - the only limit is how many credits you have.

= Non-video game examples: =

Web Comics

 * In Erfworld, as part of the general "the world's reality works according to turn-based strategy game rules" premise, units (including people) pop into existence as adults with basic skills and knowledge already in place. Not to speak of the cities, which build their own facilities, libraries included, the same "day" you pay their cost.