Recent comments in /f/explainlikeimfive

gordonjames62 t1_je2yrer wrote

Reply to eli5: How did people build bridges over deep and/or dangerous water if they didn't have the equipment to go under water? by Internetscraperds9

There is some really cool engineering tricks involving a thing called a caisson.

https://en.wikipedia.org/wiki/Caisson_(engineering)

Basically it is a box to keep water out while they build the footings.

Build the box, pump water out, work in the relative dry while hoping pumps keep working and the box doesn't leak.

Another tool they used was driving pylons or piles deep into the ground. These could be put in place from barges or other floating platforms.

Another kind of bridge is like a rope bridge.

Send a small rope across with a projectile (or a person travelling the distance by boat and/or on foot) Use this rope to pull a larger rope across. Keep on bringing rope/cable across the gap until you have enough strength / support to build a bridge.

There are different types of bridges for different kinds of challenges.

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OneNoteToRead t1_je2w7pd wrote

Reply to Eli5: What is a game engine and how does it work? by Griffinkeeler

A game engine contains all the common tools used to make video games. Among the bigger components are - graphics/rendering engine, which draws the game world onto the screen in real time; a physics engine, which simulates real world physics for objects in the game, including detecting collisions; and other software-related modules that are commonly needed by games, like a domain specific scripting, asset (textures, levels, etc) management, networking, etc.

These are typically things needed by most games. If a developer didn’t use a game engine they’d have to code it specifically for the game. For example if you wanted to write a game without using a pre-canned rendering engine you’d have to figure out the graphics math, communicate with GPU, and optimize for running in real-time.

If the innovative feature of a game is unrelated to any of the standard components, it usually is beneficial to just pick an engine off the shelf (and pay licensing fees). This is why a lot of modern games look and feel the same these days; they get to reuse the basics and really invest into the idea that makes that game unique. It’s only rarely that a game requires a totally different renderer or totally different physics engine.

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le_sac t1_je2uy7j wrote

Reply to ELI5: How is a high level of precision maintained during the construction of a building to make sure its built square, level all around? by phenols

Not to be contradictory here but there are building systems that need precision.

I'm currently managing a site with a complex structural steel frame and the anchor bolts/ embed plates have to he bang on as cast into concrete. Tolerances within our spec are 1/8" in any direction.

This is generally accomplished through professional surveying. In theory, competent execution will give good results. I am frustrated to report that surveyor on this job made a mess out their work, it is demonstrably incorrect, and as a result expensive change orders have had to go to our steel fabricator to adjust connections at base.

TLDR, accuracy is possible; but it my opinion that when all is said and done, construction boils down to cavemen banging sticks and rocks together and you get what you pay for.

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XsNR t1_je2uouo wrote

Reply to Eli5: What is a game engine and how does it work? by Griffinkeeler

Imagine you're making furniture, you can build it entirely yourself from scratch, or you can buy something from IKEA and modify it how you want, paint it, add draws, do what ever you want, but you bought the base pre-made which saved you time, and tools required to make the IKEA part.

A game engine is similar, its the base of a game which you could create yourself manually, or you could use something else and modify it. With a lot of engines it can be as simple as "painting" it, or as complicated as using it for an entirely different genre of game.

Examples, are things like

  • Source engine, which is primarily an FPS engine used for mostly FPS games
  • Unity engine, used for all kinds of things, primarily made for cross-platform compatability
  • Unreal engine, originally made for Unreal Tournament as an FPS engine, now expanded to be mostly a 3D environment engine, so can be used for all things from FPS/RPG games, to strategy games, and even Film creation
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TheJeeronian t1_je2u1zk wrote

Reply to comment by remarkablemayonaise in ELI5 How do scientists know probes (Like Voyager I) aren't going to get swept up in the orbit of another celestial body? by remorsefulDownfall

Conic sections are just an approximation. The fairly minimal tidal gradient makes stitched together conical sections a decent approximation - when you're near Earth you follow a conic around Earth and your path around the sun otherwise mimics that of Earth.

The Earth orbits the solar system's barycenter, which approximates fairly nicely to the sun but if we ignore the sun and patch our conics around the barycenter it works even better.

The method is aptly named "patched conics".

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Throwaway08080909070 t1_je2tfuy wrote

Reply to comment by [deleted] in ELI5: How come the Earth's oxygen content isnt decreasing when everyday we have millions of engines consuming tons of ? by abrandis

You're incorrect, and should take a moment to learn about this subject, it's a fascinating one.

https://www.scirp.org/journal/paperinformation.aspx?paperid=108262

https://astronomy.com/magazine/ask-astro/2012/01/collisions-happen

https://en.wikipedia.org/wiki/Annihilation

https://en.wikipedia.org/wiki/Matter_creation

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imagicnation-station t1_je2sltj wrote

Reply to comment by jamesgelliott in ELI5: What does it mean to identify as a man/woman ? by Fakeid7

I think the reason you don't want to engage is because you know he has a point and you don't have a response to his statement.

Your argument is based on a fallacy. Trans people ONLY want to identify with a gender they feel best fits them. Then people like yourself come along and create strawmans by equating "identifying with a specific gender" to "identifying as a helicopter" and other wild comparisons.

Also, science in genetics refutes your way of thinking.

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