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Damage Systems

PostPosted: 25 Jun 2013, 12:21
by Duion
How would you design a damage system for a game, or what kind of damage system you like most and why?

1.There is the classic damage system: A fixed amount of HP and if they are drained, you are dead, this is the most simple one and not very realistic, since you are the same with 1 HP as you are with 100 HP, but if you have only 1 HP left every little thing will kill you. Picking up health packs will instantly heal you. All in all not very realistic.

2.The more arcade like one: In some modern shooters you have regeneration and hidden HP, so if you get hit the screen becomes red, but if you wait a little time you will recover and so only die, if you receive serious damage in a short time, but in the long run you can eat as many bullets as you want also not realistic.

3. Realistic damage system: Direct hits mostly cause instant death and grazing shots will seriously injure you making you lose health over time or render you immobile. Very realistic but also not fun in many cases.

4. Other one?!

Re: Damage Systems

PostPosted: 25 Jun 2013, 12:27
by charlie
All of the systems you described are linear damage models.

Of course, it depends on the style of game you are going for first and foremost. A rapid deathmatch would not lend well to something more complicated than 1-3.

I would however like to see some experimentation with a damage model that takes into account location. If you get shot in the leg, it should slow you down / affect movement. If you get shot in the arm, you should struggle to use 2 handed weapons or be limited to 1 weapon.

Of course, though, we need to know more about how you intend the game to function. Are you a super soldier or are you an ordinary human? Etc.

Re: Damage Systems

PostPosted: 25 Jun 2013, 13:02
by riidom
Maybe smth like this:
Location-based system, if this is technically doable, and then:

-Leg-hits: penalties range from slowing you down to render you immovable. This should in return offer the possibility for teammembers to carry you/aid your walking, what averages the speed of both. If the injured person is able to get into a good location, he can just camp/sniper there, this is not necessarily boring - many do so voluntarily :)

-Arm-hits: one could argue about a shaky aim, but I believe this is no fun under any circumstance, so maybe limit to "small" weapons; skip left-/righthandedness.

-Body hits: picturing some kind of internal structural damage, so these maybe lower your max-HP

Getting attention by a medic should not instantly heal you, but maybe instead allow you to moderately regenerate, up to a certain point, depending on the medic skills/equipment. I think a more realistic damage model should also lead to a (slightly) more complex healing model. Also, healing could be location-dependant too.

Re: Damage Systems

PostPosted: 25 Jun 2013, 13:18
by Duion
I think there should be not much difference in damage system for realism and super human, the super human has just more power, but the system should be similar and if you have some kind of armor this will be treated separately.
The locational damage is not so much the thing I am thinking about, it is more about how to determine when the player is dead, location is mostly a multiplicator of the amount of damage.
I want a realistic system, but also stretch it out that you can take very much damage without breaking the rules of realism too much.

So far I have the classic 100 HP system with primitive locational modifiers and a slightly regeneration to add some variation and reward you for staying alive. But I need some more variation and realism, since you cannot take infinite damage without having disadvantages or having to heal yourself somehow.
Wound damage of some kind would be good, but so far I cannot imagine how to apply it, the most simple way would be after a hit from things that cause you to bleed like bullets, you get wound damage, damaging you 1HP each second until you heal yourself, but this would interfere with the healing a bit. Or count the shots you have taken as wounds, making you more vulnerable.
What I would need are some good mathematic formulas about how to apply this.

Re: Damage Systems

PostPosted: 25 Jun 2013, 15:12
by Buch
A realistic damage system has to be location-based, as both charlie and riidom said: imagine you get shot in a foot, for instance - you'd be perfectly able to shoot, or even crawl, but you'd have serious trouble walking and running.

You said you already have implemented location-based damage multipliers, right? Then going with custom effects based on where you take damage should not be difficult. Of course, you should probably adjust effect entity so that the game doesn't get impossible once you get hit for the first time. To achieve this, you could use different hit point counters for different body parts, and then take them to calculate overall effect and global HP. Details on how this gets calculated should depend on the stats system and on the difficulty of the game, so giving mathematic formulas about this is pretty hard at this point, without knowing that.

As for healing, there aren't many realistic ways to do that. Health regeneration is not the way to go, if you want realism, as well as instant healing systems (whether they are doctors or medic kits). In real life, as far as I know, even a small wound takes a while to completely regenerate, and if you get shot it can take a long time for that. You could use some medic kits with limited power (that, for instance, restore your health only up to a point, depending on what kind of wound you have) and have them location based too...

Re: Damage Systems

PostPosted: 25 Jun 2013, 15:37
by NaN
How about going somewhat realistic. Instead of HP you will have blood pressure. Every location will have a bleeding factor, means a hit in this location will cause blood pressure loss at a certain rate, which has to be treated by medic/health pack before blood pressure gets critical. Low blood pressure will also affect stamina (ability to run, jump, weapon control). Additionally, as suggested above, hits in certain locations might cause movement constraints due to tissue damage.

This could be quite fun imho.

Edit:
The healing efficiency might also depend on the severity of the wound, just reducing blood loss instead of stopping it. And you could introduce infusion bags to be able to recover blood pressure, hehe.

Re: Damage Systems

PostPosted: 25 Jun 2013, 15:52
by riidom
(there have been a few posts in meantime, I am mainly referrring to my own one above here)

Ok, trying to add formulas (any constants are ofc heavily subject to tweaking and ingame-testing, so consider these as not much more than random guesses for now).
Assuming a default Max HP of 100, and everything that is called damage, has been tested against armors etc. already.

Leg-hit:
-reduce walking speed by half of the damage (a 30pt hit leaves you with 70HP and 85% walking speed)
-reduce running speed by full damage (example above, 70% running speed)
-reduce jumping/climbing capability as well (either gradually reduce values like jump-height, as in examples above, or find a threshold where you completely disable it, for example: running speed < 50%: cant jump anymore)
Body-hit:
- reduce max HP by 25% of the damage, a 30pt hit leaves you with 70HP and 92 max HP
- calculate imaginary arm- and leg-hits with 25% of the damage each and apply the secondary effects of this as well (reduced speeds, weapon usage capability etc)
Arm-hit:
- have a "use with up to X arm damage"-value, that is somehow proportional to weight/size for each weapon, and compare with the sum of all arm wounds. It wont be usable, when damage is higher. An exception could be when you fire it laying, but standing up should lead to an auto-drop of the weapon then.
Head-hit:
- here you could introduce some fancy visual disturbations, and have the character be hard to control, for example, merge the player input with some random values, for turning and moving. Multiply the heaviness of the effect with the damage, and let it happen for (damage/2) seconds.
I am assuming here that the player model wears a helmet and thus damage gets reduced to small amounts. For a direct, unprotected hit, there are not much alternatives to "game over".

Since this is kind of complicated, it needs to be properly communicated. Having a humanshaped-icon, with the different areas filled with a colour (green-yellow-red), is a good start, additionally there could appear icons that indicate limited jumping capability (I would rather not show numbers here, try everything with colour-coding, and icons for walking, running, jumping etc.)
For weapons there will be probably icons anyway, you could overlay these with a blood-drop icon or similar, to show that this weapon is not usable due to vulneration.

Healing:
You need to keep track of each wound, the amount of damage and the area. A medic would see these list of wounds then (while aiming at certain body areas e.g.) and decides which to heal. Here you should provide full info, with numbers and each side/secondary effect listed. This way, playing a medic a few times will help every newbie to understand the damage system.

Bleeding:
The effect should be moderate, maybe 1HP/10 secs per wound, since this can sum up quickly. And it should be able to fix this even without proper equipment, but might take longer time then (as in, improvise it with a piece of fabric etc.) Else it can be plain frustrating, if you are without team and equipment and see the clock ticking.

Regeneration:
While it is true, that a "real" regeneration takes much time, there is something like "borrowed regeneration", what you can apply, since the timeframe of such a match (or mission) is rather short. Here you just steal additional energy from internal reservoirs. That is a bit abstract and vaguely now, I cant describe that better, I just hope you know what I mean. In terms of game, this could mean, that you regenerate (if no bleeds active) by a slow amount, while not moving. Maybe the same speed as a one-wound bleed is fine here, just inverse direction of course.

Re: Damage Systems

PostPosted: 25 Jun 2013, 16:22
by Julius
I always like the bleeding systems where you had to stop and bandage yourself or you would die rather quickly (and leaving blood trails in game for your enemies to follow is pretty awesome too... even for setting up traps ;) ). Painkillers/Adrenaline that restore some health temporarily, but instantly are also a cool idea.

Other than that I would at most implement a separate head shot hitbox, as all those other location based damage models are IMHO package box features and have little to no relevance for actual game-play (the shots are too random and the enemies too small in most cases anyways).

Edit: Another idea that has not been tried previously I think, would be to link health to in-game action. E.g. if you sit quietly in a corner (camping) you die quickly, but if you are pumping with adrenaline from all the near deaths and kills, your body almost forgets that he is supposed to be dead ;) (kind like those stories about real-life super-human strength or endurance during extreme events or after accidents).
Edit2: Could be a like a "time extension" with cool announcer sounds sort of over the top implementation once you reach a certain "super-human" stage :D

Re: Damage Systems

PostPosted: 25 Jun 2013, 17:27
by Duion
@riidom
That is already a good concept.
But one thing I maybe forgot to say, my goal is to use as little HUD (images, text, numbers etc ) on screen as possible, since you don't have information in your field of view in real life.
I want to make the player feel it, through physics, sounds, screen effects, postfx effects and so on.
Also I have Energy value to work with, which is used for sprinting and jumping and another kind of energy would be also possible for using with adrenaline or so.
For wound damage a good exponential curve would be good, so wound damage gets lower over time, but stays a long time, if you do not bandage it.

Re: Damage Systems

PostPosted: 26 Jun 2013, 11:59
by mdwh
I think a key point is, as you say with number 3, that realistic means not fun to play. A single shot will often kill or incapacitate.

RPGs are often comically unrealistic - as noted above, where people are unaffected by repeated blows, and then suddenly die. But how does it work in real life? A single blow from a sword will likely do serious damage, and the main way to survive is to not get hit at all.

In both cases, healing is something that can take months or more, not done quickly with a first aid kit or a few hours of rest. (Baldur's Gate at least made the point that the resting time was so you could cast sufficient healing spells, and not that you healed from the rest... - I'm not sure if this was a D&D thing or just Baldur's Gate)

A realistic system would change the way the game is played - with the idea being that your player is good enough to not get hit at all, and if he does, it's likely to be game over unless he's lucky and it's just a graze.

I think it's not a question of being more realistic - because it's never going to be very realistic anyway - but a case of "can we add complexity, in a way that also makes the game more fun or interesting to play". I think body-location is a good one, but one must be careful not to make the effects severe or long lasting enough to annoy the player (or simply make them reload from a save game).

Re: Damage Systems

PostPosted: 05 Jul 2013, 19:27
by beoran
Iter Vehemens ad Necem (IVAN) (http://ivan.sourceforge.net/) had a body-parts based system. It was hilarious, since your body parts could be transformed through magic or miracles into all sorts of materials from steel to banana flesh. It's a roguelike game though, so the fact that you died a lot was given.

Re: Damage Systems

PostPosted: 05 Jul 2013, 23:35
by charlie
mdwh {l Wrote}:I think a key point is, as you say with number 3, that realistic means not fun to play. A single shot will often kill or incapacitate.

This is not a true statement.

Perhaps you meant to say, "realistic damage means you have to cater the gameplay to it otherwise it won't be fun to play."

Sneaking, hiding, other such mechanisms become far more important when you die more easily. Teamwork becomes more important.

In a standard fare deathmatch game where you die, respawn, re-engage then I agree that it would suck albeit instagib is popular in some circles.

Re: Damage Systems

PostPosted: 06 Jul 2013, 20:33
by Duion
I like the damage system in Arma 2 although I do not understand it yet. But it is very realistic, since the game is also realism based. Sometimes one hit instantly kills you, but in other cases you can take quite a lot without dying. As I could find out so far it depends on where you get hit, with what kind of weapon and from how far. In some cases when you are far away and do not have a high power weapon, you need to hit up to 5 times to kill someone, or maybe more.
On the other hand there are several ways the game tells you that you are wounded, first your aim gets bad, but this is also when you have sprinted a lot, then the player shouts randomly "ouh that hurts" and in the worst case your leg is broken and you can no longer walk, but that's it.
In later versions like the mod DayZ you also have blood and lose blood if you are hit and if your blood runs out the screen becomes colorless and you pass out if you are too low on blood, to avoid that you can bandage yourself and/or fill up your blood with infusions or eating.

But the problem is, I could not find out the algorithms of it so far, or find some good ones my own.

Re: Damage Systems

PostPosted: 07 Jul 2013, 01:57
by mdwh
charlie {l Wrote}:
mdwh {l Wrote}:I think a key point is, as you say with number 3, that realistic means not fun to play. A single shot will often kill or incapacitate.

This is not a true statement.

Perhaps you meant to say, "realistic damage means you have to cater the gameplay to it otherwise it won't be fun to play."

Sneaking, hiding, other such mechanisms become far more important when you die more easily. Teamwork becomes more important.

In a standard fare deathmatch game where you die, respawn, re-engage then I agree that it would suck albeit instagib is popular in some circles.
Well certainly it's possible to have games where realistic death doesn't detract from the fun (e.g, adventure games), but I'm not so convinced in the context of games where combat forms a main or significant part of the gameplay.

Re: Damage Systems

PostPosted: 07 Jul 2013, 13:52
by riidom
A reinforcement-like system could be of help here.
Each player has one professional trained and equipped fighter; another semi-professional one; one out of a palette of "specialists", like medic, engineer, whatever fits in the game, and 3 armed amateurs.
If you picked one, you cant change, unless you sacrifice him.
This gives you kind of a strategical problem in first place, start with the best and push, or use an amateur to scout/get overview?
Also, it gives you kind of 6 lives, but since they are pretty different, I believe it wouldnt feel like "respawning".

One might argue, that it is frustrating to use a weak character against a strong one. This can be avoided, if the balancing is done in a way, that weaker characters have a few advances over stronger ones. I was thinking about Battlefield 2 here, fighting without a vehicle against a tank. Even if being no enemy in a simple comparison, the vehicle-less guy has a few advantages, like more agility, better overview, able to make usage of smaller cover etc.
Similarly, the amateurs could be sneakier, slightly faster than the soldiers. Maybe there are civilian NPC's too, that shouldnt get killed (otherwise some kind of punishment happens) - and with a command, the player can let the AI take over his character and blend him this way in the npc crowd.

Re: Damage Systems

PostPosted: 03 Oct 2013, 12:49
by dusted
I actually think rapid FPS games benefit greatly from realistic damage systems, just think about how Instagib gamemodes feel so much more realistic, in that when you shoot someone, they die, and if you get hit, you die.
Anyone remember ActionQuake?
Most weapons would kill you with one headshot and a shot to the legs, and legdamage made you unable to walk well, leaving you a sitting duck.

Re: Damage Systems

PostPosted: 04 Oct 2013, 13:33
by Duion
Instagib is also not realistic, what many not know, that in reality a bullet hit does not immediately kill or even stop an enemy. Only man-stopping munition has the ability to stop an enemy immediately through design that makes more energy being absorbed, but it does not always kill, some munition is designed to only stop and not kill. Normal munition that just pierces through has not much man-stopping power, even though bullet hits in reality are much more lethal, some people may can take a lot of shots without being stopped, if they are full of adrenaline and so are still able to fight for some time.

In games this could be done with some sort of delay, that even though you are probably deadly wounded makes you still able to act for some time, maybe 10 seconds, depending on your wounds, or even a little wound can kill you, but only after several minutes without bandaging. For example you get hit and still can walk around for 2 minutes, then you become unconscious and after 2 minutes of that if no one helps you, you are dead.
Or some sort of adrenaline level, this means the more action you provide, the more adrenaline you get and the better you can fight and take damage, for a short time.

Re: Damage Systems

PostPosted: 09 Oct 2013, 09:44
by dusted
*feels* much more realistic, there's real consequence of being hit, since we can't (yet, unfortunately) apply real, full-scale pain to players (though i guess a usb activated stungun may be interesting).

[edit]
I do like your idea of making a "lag" on death, maybe influenced by some virtual adrenaline (like recent pace of movement, number of recent kills and number of observed "friendlies" going down)

Re: Damage Systems

PostPosted: 09 Oct 2013, 12:56
by Julius
Which is pretty much the "action" idea I described previously, right? You are just looking at it from the other side, e.g. how to make it realistic, while I think it could also become an "fun" element of a quick shooter (kind of like the king of the hill mode).