An Examination of Physics in Video Games | Hacker News Reader

An Examination of Physics in Video Games

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>If the physical forces are too lifelike, it can ruin the fun factor. For example, imagine what it would be like to play Grand Theft Auto V with unforgiving physics — there's a mod for that by the way.

There’s an entire game for that, GTA IV. Not sure if “fun” is a right term for its plot, but that ruined nothing imo.

Apart from gta, I think physics and realism advancements look funny before the fact that in most 3d games you still get stuck in floor irregularities while running and die trying to get around that invisible wall. Or that you can wipe an armored squad with a plasma weapon, but has to find a key to a wooden door. Or that your superexoskeleton cannot do pull ups. Or that you shoot one of guards and after a couple of minutes their buddies calm down and lose their interest in the event. Like, you know, our guards die twice a day, not a big deal.

I wish realism fixed that instead of waving tents and accurate explosions.

> There’s an entire game for that, GTA IV. Not sure if “fun” is a right term for its plot, but that ruined nothing imo.

At least to me, it was more fun. To me the whole fun of GTA games was driving around while in between missions, GTA V completely ruined that part of the game for me.

Needing to find the key to a flimsy office door while equipped with grenades and a rocket launcher was always a pet peeve of mine when gaming :P

Fallouts 1 and 2 let you force some doors open if you had high enough STR and/or a crowbar. You could also blow them up with explosives.

In Wasteland 2, there's a specific Brute Force skill and you can attack pretty my any object that you can interact with. If you have high strength and/or big enough melee weapon (or dynamite), you can bypass most Brute Force checks (but also make a lot more noise in the process), and break down a lot of doors.

I agree that far too few games let you take a genuinely destructive approach, except for specific scripted instances.

In many driving games, the vehicle center of gravity is so low it's well underground. Which is why they don't roll easily.

This also compensates for video game cars having crappy suspensions.

I found the driving in GTA IV to be very enjoyable, it felt a bit like driving in an American 1970s action movie, powerslides and bouncy suspension everywhere. In that regard, the driving was very similar to that in GTA III, Vice City and San Andreas.

In comparison, the driving in GTA V is much more arcade-like, like a racing game. That obviously made the racing segments more controllable, but I think it lost some of the charm.

I'm pretty sure I dropped GTA IV mostly because of how awful driving felt. And it's a game with a lot of driving around. Interestingly enough, I didn't had the same issue with riding in Red Dead Redemption, which felt very good.

Successful implementations of game physics often has far less to do with realistic simulation and far more to do with sensation. For anybody interested in diving deep, pick up Game Feel by Steve Swink[0]

[0] https://www.amazon.com/Game-Feel-Designers-Sensation-Kaufman...

With platformers, if you want satisfying physics, you have to turn up the gravitational constant way up, increase the force of everything even more, then add artificial hangtime to jumps. Which is nothing to say of being able to change direction in midair with no external force acting on it.

Yup, platforming physics with a 5'10" character and accurate to real life gravity feels awful.

Although perhaps that's because platformer characters behave more like small jumping insects a few millimeters tall, and that's where we should go for "realism" that still feels good.

Being able to adjust momentum midair compensates for the relative lack of control over launch velocity in most control schemes. In real life, you've got a lot of control over where you land, but you don't need midair momentum control for it.

Yes, games with momentum based jumps that can't be corrected like La Mulana and Unepic feel really weird at first.

Making video games with physical elements is about clever approximations and gimmicks to make things seem physical, rather than simulating the physics outright.

Video games are basically all clever approximations and gimmicks. Once in a while, the realism wave sweeps through, and people start touting realiatic physics, or physically-based rendering, or advanced AI systems. But it's generally not all that fun, doesn't feel right, and doesn't give designers the knobs and levers they need to fine tune things and dial them in without chaotic effects.

Exactly. It's a lesson that developers of Breath of the Wild taught us: physics don't have to be realistic, they have to be a believable approximation. Same idea really as in most platformer games: you don't want an accurate reproduction of a human jumper, you want a a believable approximation such that it is joyful to just jump around.

I was originally only thinking about realism and believability on a computational budget, but you're right, the aesthetic qualities of the physics in a video game can be the difference between fun and soul-crushing.

Even ridiculously bad physics can be a goal in itself. Games like that are very much Twitch/YT bait these days.

A pretty good example of where physics have gone in video games is in pinball, pool and golf sims. The earliest of these generally had very simple ball movement behaviors and the constraint solving, to the extent that it existed as a concept, was designed to execute fast and model physics sometimes. And this remained basically true through the 16-bit generations.

But by the mid-90's it was just starting to be possible to do it somewhat right. There were a lot of pinball, pool, and golf games released in this time frame, as well as some of the early physics puzzle games(namely The Incredible Machine).

So by now you'd imagine it's close to perfect, right? Well, not really. Most video pinball games still emphasize the "video" part of it. Bounces are muted, the ball rolls a bit too smoothly, and the flipper angle dictates the shot trajectory more than in reality. And the same is true with other genres: there are plenty of things not modelled.

The best sim games are much better, but they still have their lingering issues.

I'm surprised the article didn't mention bunnyhopping or other kinds of physics exploitation-based gameplay. It could also have talked about games like Rocket League which rely on completely impossible physics to make a fun game.

Bhopping in most cases is about carrying built up momentum by jumping again before the movement system returned your speed back to normal.

Movement systems were programmed independently to collision. Physics is mostly used for collision in a standard first person shooter. You can use it for 6dof space or underwater vehicles.

why did bunny hopping exist?

as far as I remember, it was to do with jumping sideways being a lot faster than other movement, but I can't imagine why you'd program that in?

The player can jump both forward and sideways with a maximum speed. If you do that both at once the end result is you exceed to maximum speed diagonally. Now if the player is on the ground he brakes to the maximum speed. So by keeping contact with the ground as brief as possible you maintain more speed.

The classic way to get this accidentally:

- if "forward" key held down, add unit motion vector to position

- if "left" key held down, rotate motion vector to left and add it to the position

In that case, you've added two copies of the vector at 90 degrees to each other, and the player moves by sqrt(2) times the normal speed.

I think it was more about making it difficult to be hit. Both because of the irregular movement, but also because rockets exploding on the ground causes damage, and being off the ground saves you (hence good players always aiming the RPG at the ground under the opponent).

>For example, imagine what it would be like to play Grand Theft Auto V with unforgiving physics — there's a mod for that by the way.

A mod? GTA IV! The article should of showed a gameplay clip of gta 4's racing and especially the car damage physics. It's far more complex than what gta 5 offered. I was hoping to see a gta 4 mention lol

The tyre model in Rfactor 2 is something to behold, relatively cutting edge let alone for a video game.

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