grenades MUST be more lethal

[Trauma.au 10]

Huh, I got a triple kill off 1 grenade the other day, dmg is fine. Throwing modes is what we need.

[Zatan13th 10]

Brigade E5(also 7.62) does a good job in simulate the fragmentation

[John Kozak 14]

I think DMarwick understands, he just has a better idea of what a grenade produces. Modern grenades are designed to fragment evenly and into many pieces, hundreds to thousands, unlike in WW2 where fragmentation was unreliable and larger fragments produced. I can remember reading that some of them were dangerous to the thrower so the advice was throw and hit the deck.

Some examples of modern grenades from Janes '92 Infantry Weapons:

US M545 comes with three fillings 150x1g, 225x0.5g or 1300x0.12g.

Austrian HG84 5,000 pellets

Austrian HG85 3,500 pellets giving 8.1/m3 at 5m

Belgium M72 - 900

Obviously you cannot simulate these numbers.

Instead you would be better to look at the targets inside a radius of effect, and then adjust for line of sight, profile and stance.

Most offensive grenades seem to be listed as lethal at around 5m and casualty producing up to 10-15m.

Defensive grenades have slightly bigger pellets that travel further so the ranges are a bit longer.

Yes, I agree that probabilistic model would be better. BUT not the probabilistic model DMarkwick described - because it's just plain wrong, as I demonstrated above. Doing a proper statistical model isn't as simple as saying "okay, let's say X happens in Y% of cases". There are distributions, mean values, correlations, etc..

Problem is, it's very hard to get right - as demonstrated in the above example. Imagine one more lineage of bugs adding to the already rich on that ArmA.

Plus, there are old grendades like RGO and M26, which produce small number of heavy shrapnel pieces. RGO's shrapnel can (with low probability) hit targets at a distance of 100m - imagine that. And with such cases, "proper" simulation is just plain better - because it (surprisingly) would require less calculations.

Edited August 17, 2013 by DarkWanderer

[Dwarden 1125]

you need also to take in mind if the grande is defensive or offensive ... that's huge difference in actual kill zone radius

offensive grenades get kill zone of around dozens meters max

defensive grenades can kill in 100m range

ofc this depends on nade model

[Bee8190 10]

So whichones have we got?

[roberthammer 582]

So whichones have we got?

From the model - its this one http://en.wikipedia.org/wiki/M67_grenade - this grenade is not weak :p

Edited August 17, 2013 by RobertHammer

[Niklas 1]

I just tested this in the editor, grenades are fairly effective against enemys, but for some reason it is impossible to kill yourself with a single one even if you throw it at your feet.

[dmarkwick 261]

If you have probability 0.5 and 10 objects near grenade, you have 5 hits (5 effective pieces of shrapnel) on average.

If you have probability 0.5 and 100 objects near grenade, you have 50 hits (50 effective pieces of shrapnel) on average.

Sorry, but you didn't even understand what I'm talking about. Read again.

I don't understand what you find wrong about it, it sounds fine to me.

[heruon 1]

I just tested this in the editor, grenades are fairly effective against enemys, but for some reason it is impossible to kill yourself with a single one even if you throw it at your feet.

I just tested with a grenade at my feet and it killed me instantly, as usual. Going prone 2m away from didn't help either. Are you using extended armor?

[John Kozak 14]

I don't understand what you find wrong about it, it sounds fine to me.

Okay, let me explain this part...

First off, let's do a small classification. Historically, there are two main types of grenades: offensive and defensive.

• Defensive grenades are thrown from cover and have small number of heavy high-energy fragments, which give an effective radius of 30-40m. Prolific example: F1 grenade. Note the cuts on the grenade casing - it will always produce 30-something fragments
  
• Offensive ones are designed to have limited range and more-or-less constant shrapnel density in hit sphere. For this reason, they use fragmentating wire or small steel balls (or casing with large number of cuts) to produce small fragments which quickly lose velocity in air, resulting in effective radius of 10-15 meters. Examples: M67 grenade, Russian RGN (Ð ÑƒÑ‡Ð½Ð°Ñ Ð“Ñ€Ð°Ð½Ð°Ñ‚Ð° ÐаÑÑ‚ÑƒÐ¿Ð°Ñ‚ÐµÐ»ÑŒÐ½Ð°Ñ - Offensive Hand Grenade)
  

These two types give us two distinct patterns:

1. Small-fragment burst: can be modelled as a sphere, originating with a small radius at the moment of explosion and extending with the fragments flying; this means, any target will be hit with the number of shrapnel proportional to its solid angle as viewed from the center of explosion and with energy of each fragment inversely proportional to square of distance.
   
2. Large-fragment burst: limited number or fragments evenly distributed on sphere. Here, distribution of individual pieces starts to matter.
   

Let's test your model on both cases:

1.Test on small fragment burst

Let's imagine 5 targets standing at 2, 5 or 10 meters from explosion in the open. Your model gives some fixed probability for each target to be hit - which will leave some targets unscathed. This obviously won't happen - as there is a lot of fragments flying all around. All targets will be hit more or less equally.

Correct model must hit every target (as distribution is spherical) and calculate penetration and damage based on the energy of hit - i.e. body armor will not withstand the fragments up close, but will be able to stop them at distance.

2.Test on large fragment burst

This case is a little bit more complex. Let's first perform a thought experiment with simplified terms.

The setup would be as follows:

1. Custom-made IED with 3 fragments flying with 120 degrees offset in horizontal plane
   
2. 6 targets standing evenly around the IED (60 degrees offset), numbered clockwise
   

(sorry, can't attach a picture from workplace)

When such a device explodes, we'll have one of two cases:

1. Targets 1, 3 and 5 are hit
   
2. Targets 2, 4 and 6 are hit
   

The probability that each individual target hit is, hence, 1/2. However, what's certainly not possible is that targets 1, 2 and 3 are hit and three other targets are not.

This is what the catch with probability simulation is: your model treats events "target 1 is hit" and "target 2 is hit" as two independent events. However, in reality they are dependent on each other.

If there is one fragment in a given solid angle section, it will hit only one target and can't hit two. That's what I meant by the phrase on effective shrapnel pieces number - suddenly, there spawns many pieces where only one should be.

The case with a real grenade and real target configurations is much more complex, of course. But using a naive probability model (as you described) is going to give a lot of WTF factor where there shouldn't be (example - throwing a grenade into a group of soldiers will kill all the soldiers west of it, but leave all on the east unharmed).

Edited August 20, 2013 by DarkWanderer

[RushHour 11]

Here´s the inside of a frag grenade, quite interesting seeing the mechanisms of it.

http://i.imgur.com/FvWF19q.jpg

[dmarkwick 261]

Okay, let me explain this part...

Thanks for taking the time. I didn't realise there was a distinction between defensive & offensive, I just thought there were different designs :)

So it sounds to me like "offensive" grenades would be better served by a pure distance-to-origin check followed by a shielding obstacle check? In any case it sounds to me like a dense shrapnel scattering (of the density implied by the offensive grenade description) is an expensive way to do this.

[Beagle 684]

Another scheme of a moder rmodern type of Hand grenade using 2500 steels balls as shrapnel filler. DM51a

Manufacturere data (german and english language)

http://www.diehl.com/fileadmin/diehl-defence/user_upload/flyer/2010_Flyer_Handgranaten_11_2010.pdf

Edited August 20, 2013 by Beagle

[John Kozak 14]

Thanks for taking the time. I didn't realise there was a distinction between defensive & offensive, I just thought there were different designs :)

So it sounds to me like "offensive" grenades would be better served by a pure distance-to-origin check followed by a shielding obstacle check? In any case it sounds to me like a dense shrapnel scattering (of the density implied by the offensive grenade description) is an expensive way to do this.

Yes, basically it's how it should be done.

Ideally, there would be several checks for various body points (because, for example, player might be partially hidden behind a light pole => simple centerbody shielding check will give a false negative). Without it, direct shrapnel simulation is more accurate here - because it can hit any part of a character not hidden - but yeah, it'll be awfully expensive :)

I doubt the full check of the first type will be implemented, though. I got a feeling they'll stick with current design for a while.

Edited August 20, 2013 by DarkWanderer

[dmarkwick 261]

I doubt the full check of the first type will be implemented, though. I got a feeling they'll stick with current design for a while.

Agree. I prefer pragmatism & performance-based solutions myself, as long as , in general & on average the effect is appropriate in most situations, it's a good one :)