Ask GR Anything: What’s a game engine?

Ask GR Anything is a weekly Q&A column that answers questions submitted by readers (as well as questions we're particularly curious about ourselves). Got a burning question about games or the industry? Ask us in the comments below and you may just get it answered!

When we started this column a few months ago, we did so with the intention of focusing on educating readers about many of the gaming industry’s nagging questions. But last week, user Dmancapri asked a very interesting question. The gist of it was: what exactly does it mean when we hear game companies talk about “game engines?”

While this is sort-of “no-duh” territory for a lot of seasoned gamers, we realized that there are probably a ton of younger and more casual gamers out there who see this term all the time, and aren’t really sure what it means. In fact, quite a few of the hardcore probably have only the most basic understanding: engines help devs make games.

Above: The idea is to pay a bit of cash so your coders can do as little of this as possible

So we contacted an indie programmer friend-of-a-friend to help us distill this topic down to its most basic level. "A game engine is not unlike a car engine: it drives the game on the lowest level,” said indie game designer and programmer Dan Cox. “When you turn the steering wheel or press down on the gas pedal in a car, you are providing input to some software that is telling the car how and when to move. Programmers and designers, in the case of games, can work on this software knowing that the engine will do the moving. They just need to tell the engine what to do when the player (or driver) takes certain actions."

Cue the angry tech folks to rage in the comments about how wrong we are. Take a deep breath, tech folks. We’re trying to make a very not-simple subject simple. There’s bound to be some dissonance between the reality and the simple explanation.

"Game engines take care of most of the hard work for the programmer,” said Cox. “Instead of having to worry about writing all the code to draw certain things or play sounds at different times, the programmer can tell the game engine to do that for her. Instead of spending time on writing all the necessary code to get common activities done, she can spend more time on the game itself."

In other words, the engine takes care of the gruntwork, the enormous mess of coding that comprises a major game production. This way, rather than spending all of their time wrestling with code, artists can focus on artist things, and designers can focus on new ideas and honing the game’s overall design.

Above: Unreal Technology has been the most popular recently, but many others exist as well, including Crytek's CryENGINE and Rockstar's RAGE

“Videogames are very complex,” Cox elaborated. “Each main area - graphics, audio and handling input - requires its own special code to do common things. When working on a game, the programmer wants to spend time on the game itself and not writing their own code to draw things on the screen, for instance. Game engines help them with that. They provide a standard way of doing things, a way that everyone on the team can use without worrying about it changing. A game engine can often decrease the complexity of making a game and allow the programmer or designer to create a game in less time and with less effort.” 

In addition, sometimes specialty engines are created to handle complex tasks like physics. The Havoc Physics Engine was extremely popular for several years because it allowed developers a simple method (pay money, get physics) of implementing a complex physics system that would ordinarily take many man-hours to code.

So why are some engines so much more popular than others? It seemed like not a week went by in 2010 without some publisher bragging that their next game will be done using the Unreal Engine 3. Who cares? Well, a lot of people care, and that’s one of the big reasons why so many companies used UE3.

Above: Gears of War 3 was made using Unreal Engine 3

At one point, using UE3 was an automatic boost in attention for your game. It signaled to gamers (incorrectly) that a game deserved to be taken seriously. Recently, that has fallen out of practice, thanks to horrible crap-piles like Hour of Victory and Leisure Suit Larry: Box Office Bust infecting the engine’s reputation.

However, there’s another method that companies like Epic use when promoting their engines. Cox said they make their software available for free to students and other projects. The objective is to create a new generation of coders who are most comfortable using their company’s software. It’s the same reason companies like Adobe make Photoshop and InDesign much cheaper for schools than for-profit corporations.

Above: Unfortunately, Box Office Bust was also made using Unreal Engine 3

Once the engine gets sufficiently outdated, companies will usually release it to the modding community. Epic and Valve have both done this with Unreal Engine 2 and the Source Engine. This provides extra content for their games, but it also educates modders in their software. And when those modders eventually create something impressive and get hired, they’ll bring that preference to the companies they work for. 

Submit your own questions in the comments (or Tweet them to @sciencegroen) and we may tackle them for a future Ask GR Anything.

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  • bensmiley45 - May 6, 2012 10:33 a.m.

    I wrote a detailed article about what a game engine is from the perspective of a developer. Specificially for the context of iPhone and Android games. Here:
  • bensmiley45 - May 6, 2012 10:30 a.m.

    I wrote a detailed explanation of what a game engine is from a developers perspective - specifically in the context of iPhone and Android. It can be found here:
  • TehWise - January 21, 2012 9:22 p.m.

    A related question. What is really the "pause" in a game?
  • Andrew Groen - January 23, 2012 9:18 a.m.

    OooO. I like that. I'd like to know that as well. I may have to look into this.
  • Andrew Groen - January 19, 2012 10:09 p.m.

    But the people call for it, Sinosaur! One of these days I'll have to contact a theoretical physicist and make them watch Pokemon cartoons to try to come up with theories for how they could work.
  • Ravenbom - January 19, 2012 1:01 p.m.

    I know what screen tearing is but it's one of those terms videogame reviewers use that most people don't understand. Perhaps a small lexicon of these terms, like screen tearing, volumetric lighting/smoke, upscaling, etc... I understand these terms but only because I looked them up after reading them in reviews. There's a couple other terms that get thrown around that I can't remember right now, like dynamic shadows or lighting or something like that. I think there's also deferred shading I read in some pompous Gamespot review one time. There's so many terms that they become hypocognized; you don't even think of them anymore.
  • BladedFalcon - January 19, 2012 11:14 a.m.

    Pretty good article! ^^ To be honest, I'm one of those people that has heard about engines and such for years and years, but never really understood what they did. This was a really good, well written explanation that has given me a clearer, simpler idea of how they work ^^ I'm still curious about that question I had made weeks back about why companies were hellbent on releasing their more obscure games in dates that apparently everyone but THEM were aware that it was a terrible date to release such game. (Ubisoft seems to be the biggest offender regarding this.) Then again, I suppose taht it might not be as easy to answer this one without cooperation of the companies that do exactly that...
  • Dadyo238 - January 19, 2012 8:17 a.m.

    Was the Splinter Cell movie cancellled?
  • ray_gillespie - January 19, 2012 5:57 a.m.

    This question has been bugging me for years and I can't find an answer anywhere! How did Quake 3 use perfectly round polygons, and why the hell doesn't any use this technology anymore?!?
  • ray_gillespie - January 19, 2012 5:58 a.m.

  • Triscuitable - January 18, 2012 8:49 p.m.

    What is the first instance of profanity in a videogame?
  • EwoksTasteLikeChicken - January 18, 2012 6:08 p.m.

    How do soldiers in modern fps games re-generate health? Or, how do health packs work?
  • Sinosaur - January 19, 2012 12:35 p.m.

    They have been issued healing factors similar to Wolverine's, only not nearly as powerful and health packs work via nano-machines rebuilding the body.
  • Supermanoh - January 18, 2012 5:48 p.m.

    Why do shadows in every game ever look like absolute bollocks no matter how gorgeous the rest of the game is?
  • Ravenbom - January 19, 2012 12:37 p.m.

    That's mostly a console issue because their guts are now 7-8 years out of date. A good PC rig can handle complex shadows and anti-aliasing but to keep the textures and framerate solid consoles sacrifice shadows and AA. Lowering AA and shadow complexity is also the best way to get a PC with a budget graphics card to handle high graphics settings.
  • Jrm21 - January 18, 2012 5:30 p.m.

    Pretty good article, answered some questions I had about engines, especially my burning desire to know what Engine powered Leisure Suit Larry
  • taokaka - January 18, 2012 5:03 p.m.

    my question is where do a lot of game characters work out? I want biceps as big as my head.
  • BladedFalcon - January 18, 2012 6:27 p.m.

    ...Oi, you weren't joking about changing your avatar ._. Relax, SOPA hasn't been passed yet :P (Also, I don't feel like taking down my awesome Sol badguy avatar D:)
  • taokaka - January 18, 2012 8:55 p.m.

    I was joking but then thought I would joke around by anti-joking and changing my avatar but now I'm back to normal.
  • Cyberninja - January 18, 2012 4:12 p.m.

    nice answer, and like some other comments have been asking i would also like to learn how a pokeball works