Artistic License Engineering

In Real Life, an engineer's job is to design machines or structures that perform a certain task, and perform it efficiently, reliably and safely. It's a challenging job, involving analytical thinking and mathemathics as well as creativity – and last but not least, common sense.

Not so in fiction. When you let a writer of fiction dream up a machine, odds are good that you'll end up with something that is horribly inefficient, unsafe, or just plain impossible.

The reasons for this vary:
 * Many writers will not even think about functionality when designing a machine; they're more concerned with the "look" and "feel" their machines convey rather than whether they actually make sense given the function they're supposed to perform. This is often the case with spaceships in softer Science Fiction.
 * Even those writers that pay some attention to functionality often can't be bothered to think things through. Fuel consumption? Maintenance needs? Heat dissipation? They're the last things most writers worry about.
 * And then there's failure to think outside the box – that is, failure to consider that there might be other, perhaps less spectacular ways to get the job done. Even machines that have been properly "designed" and thought through will make no sense whatsoever if there is clearly another, much more efficient way to do what they do.

If the work is set in modern times, you're supposed to ignore it, but if it is in a sci-fi or fantasy setting, it's a toss-up whether it will be ignored completely, explained as being made of Unobtainium or Applied Phlebotinum of some nature, or only working because A Wizard Did It or a Higher-Tech Species show us how.

A very frequent cause of Awesome but Impractical. Cool but Inefficient is a subtrope. Related to No OSHA Compliance, as process safety is a pretty big issue for most engineers in Real Life.

See also: Artists Are Not Architects, Sci-Fi Writers Have No Sense of Scale, Square-Cube Law.

Anime & Manga

 * Is there anything with Humongous Mecha that doesn't fit into this?
 * Shirow Masamune, is in fact, an engineer. (Even he applies Artistic Licence though.)
 * Twentieth Century Boys features an engineer who gets kidnapped to build one and rants at his kidnappers about just how undoable it really is. Eventually, it does get built,
 * Full Metal Panic! actually used this in an interesting way: One Humongous Mecha fell apart once the Applied Phlebotinum allowing it to ignore its own weight failed.
 * Mecha in general often touch this trope. A bipedal machine is, with anything resembling modern technology (or in the near-future sans Handwavium), a horribly complex, inefficient, and dangerous way to design a war machine. Just the stabilizing and moving systems alone would be a nightmare.

Film

 * There is a lot of debate of how possible/impossible the city-planet of Coruscant is, and not least the concept of miles-high buildings and the infrastructure required to maintain them and the population they contain.
 * One notable offender is the Senate Building. Its central chamber is so large that unless the air inside was kept extremely dry, clouds would condense in the upper tiers.
 * There's also the issue of how a city-spanning planet could possibly void all the heat that it generates, not to mention the gaseous exhaust of trillions of vehicles, building systems, and industrial facilities. It's even mentioned in one novel that Coruscant somehow still has ice caps, and the characters go skiing.
 * Another: The Square-Cube Law notwithstanding, the buildings are so slender in comparison to height, that the slightest breeze would probably cause them to buckle.
 * On the subject of Darths and Droids and this trope, the players decry Naboo as being unrealistic for structural reasons...except for Jim, who it turns out is a postgraduate student getting his Phd in geophysics, and actually goes to the trouble to work out how such a planet would be feasible.
 * To be fair, considering the space ships they can build I don't think they would have an issue engineering buildings to withstand the stresses of intense wind pressure with the materials available to them.
 * Correct. The Star Wars setting has access to fantastical materials of truly ridiculous structural strength - as one example, the cockpit glass in the Millenium Falcon is tougher than contemporary tank armor. (There is a scene in Legends material where Han accidentally fires his blaster into the inside of the cockpit window while wrestling with a bad guy, and it only makes a very small hole. That same blaster has ripped man-sized chunks out of concrete walls.)
 * The chicken walkers (AT-ST's) are just walking targets. The Hoth walkers (AT-AT's) make a bit more sense, if we take into account that repulsor coils big enough to make something as big as an AT-AT float would be such an energy drain that the power plant wouldn't be feasible for mass production. The only reason two AT-AT's got taken out at all was more Luke's Rule of Cool then anything else.
 * Wookiepedia suggests that the reason for the legs was two-fold. First, a giant walking death machine is really scary, and second, Repulsor-lift vehicles are vulnerable to mines, while the extremely long legs of the AT-AT means the blast never reaches the vital components.
 * Given how the rebels destroy the walkers in the Hoth battle, though, the legs themselves appear pretty vital...
 * Various books have suggested that walkers were designed for regions where ground-level repulsorcraft were unsuited such as very uneven ground or unstable gravity. Interesting, but Tanks seem more effective.
 * They did in fact have those, but like most Imperial weapons systems, they were Awesome but Impractical, having huge wheels and being very unmaneuverable.
 * The prequels and Clone Wars series make this worse, since the earlier designs were much more effective. The Clone equivalent to an AT-AT could walk straight up cliffs, had a lower center of gravity distributed further apart on more limbs, and had weapons that didn't all face forward just for one example.

Literature
"Foaly: Everything is molecular, and if you pack gigabytes of data into a little cable, some of that cable is going to wear off. I put the MPEG through my filters. Uranium residue points to northern Russia."
 * Architecture and machinery that fits, or appears to fit, this trope is common in Dr. Seuss books, which are nonsensical anyways.
 * Electronics, in Artemis Fowl: The Arctic Incident. Apparently, data sent through irradiated cables becomes radioactive itself:


 * Trantor, the capitol of the Galactic Empire in Isaac Asimov's Foundation series, is a planet-spanning city like Coruscant in the example below (in fact, it's been suggested that Trantor was the inspiration for Coruscant). The engineering problems might be somewhat averted by the fact that unlike Coruscant, most of Trantor is underground. However, in later books in the series, people seem to have no trouble at all stripping away entire sections of the city, with apparently no concern for what it might do to the structural stability of surrounding parts of the city. Well, they do call that period "The sacking of Trantor"...
 * Thoroughly averted in the Vorkosigan Saga; all the engineering is realistic, and even the 5-space theory expounded in Komarr sounds plausible.
 * Averted in Honor Harrington, where the characters are fully aware that their architecture of multi-hundred-story skyscrapers is only possible because of countergrav. Grayson, which didn't have it, has low buildings (Also, high is bad on a Death World).

Live Action TV

 * Star Trek routinely violates sound engineering principles. If you took a drink for every time the TNG Enterprise was nearly destroyed because something like the reactor failsafes failing, you'd be comatose within a few episodes. Limited (or lack of) systems redundancy, no compartmentalization of critical systems, using active measures like force fields for biohazard containment (instead of, say, a freaking box marked "biohazard") ... the list is endless.

Video Games

 * This trope came back to bite the creators of the latest Red Faction game. Apparently the combination of their famed Geomod engine with a realistic physics engine caused the outrageous "futuristic" buildings they planned on using in the game to collapse under their own weight, forcing them to go back to the drawing board with more sensible architecture. Explained by Volition themselves here.
 * The Sims, falling under acceptable breaks of reality, since house building can take a long time without you thinking how many pillars to put to support the entire structure. Of course, there is also the bugs that allow things like a floating house.
 * Minecraft is even worse in this regard. But again, acceptable breaks.
 * Dwarf Fortress. Fortresses built entirely on one brick of soap? They've been done, and that's considered relatively insignificant. Then again, without Dwarfy physics, we wouldn't get the mind-bendingly complex Death Traps and megaprojects that Dorfs have been known to build. Case in point, DOMAIN, a suborbital Kill Sat defense network that works by pumping magma up to dozens of Z-levels above ground level and dropping it on opponents, is still making the rounds on the Bay 12 forums.
 * In the City of Heroes MMORPG, there are solar panels on the rooftops of all the university buildings... facing *north*.