It makes no sense that alien ships have no outward damage.

[moriarty]

I've never thought about that. 
Can't the grav lift be modified to be almost indestructible like XCOM crafts?

actually, the grav lift itself IS indestructible afaik. but the floor tiles around the upper level aren't

Damaged UFOs could be handled by separate map files.

sure, but that's a lot of work. especially if we want to include all the newly built UFOs like lukes additional UFOs 

[RSSwizard]

Pistol in UFO is a heavy large calibre pistol like Desert Eagle, not a typical military pistol.

I believe the ufopaedia in vanilla said the pistol was 9mm.

The rifle was also 6.7mm which is roughly equivalent to a .270winchester (which is between a 5.56mm and 7.62mm nato in power). So its not really a heavy duty rifle either. Though it does have good accuracy.

But even a Desert Eagle (44mag or .50ae) would do more damage than that rifle.


What supports it is the fact that UFO power source (/propulsion), by the descriptions, seems to not care about aerodynamics at all.

What I think the designers had in mind was, the Power Source/Engines for the ship determine if it is airborne or not.

Apparently they are pretty fragile, and the equivalent of buffeting from external explosions (like theatrical Bridge Shaking in Star Trek) can cause them to malfunction and explode when they are turned on. Kinda like dropping your laptop while copying files can crash the hard drive.

Since smaller UFOs can actually get destroyed its a fair bet to say that any actual Hull Breaching of the ship really does destroy them, not just blowing up the power source but tearing the ship apart.

So maybe the UFOs are a hell of alot tougher than expected and they only get shot down because of "shaken baby syndrome".

[Sturm]

I believe the ufopaedia in vanilla said the pistol was 9mm.

"The standard issue XCom pistol is a high powered semi-automatic with a 12 round capacity."

The rifle was also 6.7mm which is roughly equivalent to a .270winchester (which is between a 5.56mm and 7.62mm nato in power). So its not really a heavy duty rifle either. Though it does have good accuracy.

But even a Desert Eagle (44mag or .50ae) would do more damage than that rifle.

I think that X-Com uses a penetration-based damage model. Which means that higher energy and lower calibre trumps over momentum (though with .270 winchester, momentum would still be a bit higher for the rifle bullet).

What supports it is the fact that UFO power source (/propulsion), by the descriptions, seems to not care about aerodynamics at all.

What I think the designers had in mind was, the Power Source/Engines for the ship determine if it is airborne or not.

Apparently they are pretty fragile, and the equivalent of buffeting from external explosions (like theatrical Bridge Shaking in Star Trek) can cause them to malfunction and explode when they are turned on. Kinda like dropping your laptop while copying files can crash the hard drive.

Since smaller UFOs can actually get destroyed its a fair bet to say that any actual Hull Breaching of the ship really does destroy them, not just blowing up the power source but tearing the ship apart.

So maybe the UFOs are a hell of alot tougher than expected and they only get shot down because of "shaken baby syndrome".

The thing is that larger UFOs don't actually get thicker armour than smaller ones. They are just larger. On the other hand X-Com made alloy craft that use thicker armour while staying small.

[RSSwizard]

I think that X-Com uses a penetration-based damage model. Which means that higher energy and lower calibre trumps over momentum (though with .270 winchester, momentum would still be a bit higher for the rifle bullet).

Thank you, I stand corrected about the pistol.


In reality (like, real world reality) the formula for Penetration works alot like this:
60 x Mass x Velocity Multiplier x Density of Target^-1 x Diameter^-2
(units are grams, meters per sec, grams per cubic cm, millimeters for diameter)


The Velocity multiplier is LOG[ ((Bullet Density x Velocity²) + Bullet Tensile Strength) x (Tensile Strength of Target)^-1 ]

So if you have a Hardened Steel bullet shooting a Hardened Steel target at 750 meters per second (roughly high powered rifle speed) the Velocity multiplier will be LOG[ ((7.8 g/cm x 750²) +120000 Pa) / 120000 Pa ] = ~1.57 (unitless)

Completing this equation if the bullet weighs 150 grains (9.75 grams) and is 7.62mm wide the overall Ideal penetration will be . . . (this is for a 7.62mm all-steel armor piercing round)

9.75 x 94.2 x 7.8^-1 x 7.62^-2 = ~2 cm of hardened steel armor


Using the example of a .50BMG armor piercing round (43g @ 850m/s) will produce penetration of 3.45 cm against likewise armored material (which makes sense because even a standard ball round will penetrate 1.5cm of steel plate armor).

Granted its not a foolproof equation, such as when you introduce things like Incendiary Armor Piercing or Hollowpoint expansion, but it is derived from one involving alot more physics, condensed into simple logarithms rather than integrals. And it is an excellent guide for figuring out the ballpark figure (probably within 25%) where the penetration for something is going to be.

(as for my source, I found it back in 2006 at random, and have been putting it to the test ever since then, and have since lost the webpage link and documentation for it)


The relationship between Penetration and Velocity is not linear. And it increases at a slower than 1:1 ratio as velocity increases, but since its based on a number of factors its not readily apparent how it will be affected.

Evidently the Material Strength of the bullet also doesnt matter as much as its Density. But since a bullet breaking up or deforming would effecitvely alter its Diameter mid-penetration it does matter,more than this equation suggests.

And all of that was just to let you know . . . that the Energy of the shot really doesnt matter, despite common conception of it. Its more like Momentum vs. Diameter rather than Energy (and its even less than Momentum because Velocity is not at a 1:1 ratio).

If you want to increase penetration, Lower the Velocity, and increase the Mass, while decreasing the Diameter.

An ideal penetrating bullet will be long and rod-shaped, made out of Tungsten (almost as heavy as uranium), and it will be narrow. Like a Flechette. Except it needs to be wide enough not to snap under pressure so it can't be sub-caliber like the (less than 5mm) rounds developed in the 60s.

So getting shot with something cruising at poor pistol velocity could end up with more penetration than a .50, though it would be heavier and because of ballistic arc it wouldnt have as much range.

Though a heavier bullet also has better range than another one going the same speed because of Air Resistance, which acts like the bullet has to penetrate the air just as much as the target itself.


What Velocity does for you is it increases the Range of the shot and it increases the Physical Damage that it causes on impact. It does increase the penetration, but not by much. And it comes at a great cost of energy to push it up to speed.

This also debunks the notion of a Railgun having excellent penetration. Yes a railgun has good penetration but according to these calculations the realistic velocity a railgun might have (about as fast as an orbiting satellite, something like 10 times rifle velocity) . . . would only be like 2-3 times as much by weight.

What it does do is an absolutely enormous amount of Physical Damage, and have a flat trajectory arc like a laser.

(and you can forget "relatavistic" railgunss, since as soon as it fires it will generate a nuclear strength explosion from pushing the air out of the way in front of the gun, good way to kill yourself)

[Yankes]

One way to simulate damage is to roll for every outer ufo wall and if its "crit" then explode that tile. Something like current power source explosion.

[Sturm]

One way to simulate damage is to roll for every outer ufo wall and if its "crit" then explode that tile. Something like current power source explosion.

True. Luckily getSpecialType() == ALIEN_ALLOYS seems to return only the outer walls. Here's how 15% 3m radius explosions look like (The terror ship could be 25%, though. I don't remember).

The main problem is that aliens get spawned outside, so it's impossible to take casualties in-air into account.

[moriarty]

Very nice. I'd say between 0% and 7% should be enough, though... otherwise the UFO has too many entrances, and breaching it loses the thrill.

Thank you, this is a very important first step!

Do you think it would be possible to keep track of the damage values of each hit the UFO took?

[Sturm]

Very nice. I'd say between 0% and 7% should be enough, though... otherwise the UFO has too many entrances, and breaching it loses the thrill.

On the other hand you can have several exits from UFOs from which the aliens can come out without warning you with door sounds. It's also more difficult to secure every exit with mines.

Do you think it would be possible to keep track of the damage values of each hit the UFO took?

Well, it should possible. I don't have skills to program it yet, though. The damages could be written into a table or something like that would then be read when generating the battlescape, doing number and damage of "hits" based on the hits in the table. The game could run through tiles multiple times exploding them until all "hits" are used up.

[moriarty]

that's what I was aiming at, precisely

we could then define hit damage levels for different size explosions. something like this:
 60-100:  radius 0 explosion (1 tile destroyed)
101-140: radius 1 explosion (3x3)
   300+:   radius 2 explosion (5x5)

rationale:
- the standard cannon shouldn't be able to completely destroy a UFO hull tile (especially not with a single hit, because it has such a high rate of fire)
- the laser cannon and stingray should have a hard time creating a man-sized hole
- the avalanche should regularly destroy a tile, but not always
- plasma cannon should burn holes most of the time
- fusion balls should cause large holes sometimes

for reference, here's the vanilla values:

cannon:             damage 10 (5-15)
stingray:            damage 70 (35-105)
laser cannon:     damage 70 (35-105)
avalanche:         damage 100 (50-150)
plasma cannon: damage 140 (70-210)
fusion ball:        damage 230 (115-345)


small scout: damagemax 50
medium scout: damagemax 200
large scout: damagemax 250
abductor: damagemax 500
harvester: damagemax 500
terror ship: damagemax 1200
supply ship: damagemax 2200
battleship: damagemax 3000

[Solarius Scorch]

+1
This is exciting!

[Sturm]

that's what I was aiming at, precisely

we could then define hit damage levels for different size explosions. something like this:
 60-100:  radius 0 explosion (1 tile destroyed)
101-140: radius 1 explosion (3x3)
   300+:   radius 2 explosion (5x5)

rationale:
- the standard cannon shouldn't be able to completely destroy a UFO hull tile (especially not with a single hit, because it has such a high rate of fire)
- the laser cannon and stingray should have a hard time creating a man-sized hole
- the avalanche should regularly destroy a tile, but not always
- plasma cannon should burn holes most of the time
- fusion balls should cause large holes sometimes

for reference, here's the vanilla values:

cannon:             damage 10 (5-15)
stingray:            damage 70 (35-105)
laser cannon:     damage 70 (35-105)
avalanche:         damage 100 (50-150)
plasma cannon: damage 140 (70-210)
fusion ball:        damage 230 (115-345)

Note that these damages are on completely different scale than the Battlescape damages. Cannon would be more powerful than hand-held and HWP-mounted cannons as the first are limited by the ability of soldier to withstand recoil (why does the heavy cannon and auto-cannon have AP ammo by the way? And what's the deal with the multiple barrels of auto-cannon? In Laser Squad auto-cannon was HE-only and had only one barrel which makes more sense and the second has a pretty short barrel - aircraft auto-cannons are usually about 2m long and weight about 100 kgs. IMO craft's auto-cannon would do similar-level damage as heavy plasma. Which would mean a certain (about 12%?) chance for each hit destroying one tile.
Sidewinder which is a RL equivalent of Stingray has much heavier warhead than any weapon on Battlescape. It has a warhead that is 2-3 times heavier than a whole Large Rocket. Assuming all missiles rely on direct hits, all of them should be easily able to make holes in UFO. Avalanche hits would probably be very nasty.
Aircraft missiles are HUGE. Sidewinder is 3m long. Phoenix is 4m long.

The main challenge for a Battlescape damage system is that all damage would probably be located in the rear area of UFOs because interceptor is simply chasing the UFO. It seems that UFOs just fly on auto-pilot until the crew realises that they are being attacked and increases speed to outrun the interceptor.
So, a completely mangled rear area of the UFO would be be more probable than mild all around damage that is the result of re-using the Power Source detonation code.

[Dioxine]

Avalanche is NOT Phoenix... even if it looks like one. Probably a Phoenix modded for less range and more speed and/or EM shielding. And, the Pedia says it carries a nuke, convenient to forget as it might be

The main problem with outward damage is... that UFO breaching, a major feature of this game, is suddenly a whole lot easier as you can mount a multi-pronged assault. Sure, as things are in vanilla, you can  mine the exit and wait till turn 20, but abusing the routine that was meant to save the player the hassle of finding the last alien is sort of cheating. Going slightly OT I'd rather have a timer: do your thing within 20 turns or the govt is calling an airstrike to wipe the aliens out.

[Sturm]

Avalanche is NOT Phoenix... even if it looks like one. Probably a Phoenix modded for less range and more speed and/or EM shielding. And, the Pedia says it carries a nuke, convenient to forget as it might be

Oh God, these craft weapon descriptions are non-canon and absolutely horrible XD (original X-Com had no craft weapon descriptions). I don't know what the person who wrote them was thinking XD .

True, I haven't noticed that Phoenix had range of over 100 miles. Phoenix is already Mach 5, though.

The main problem with outward damage is... that UFO breaching, a major feature of this game, is suddenly a whole lot easier as you can mount a multi-pronged assault. Sure, as things are in vanilla, you can  mine the exit and wait till turn 20, but abusing the routine that was meant to save the player the hassle of finding the last alien is sort of cheating.

Aliens usually come out multiple times before turn 20 - they just don't know where the player units are. The main reason I mine entrances is to avoid an alien coming out and shooting my operatives while they gather to enter the UFO. Personally, I don't like UFOs with holes in them because ability to come out on my flanks and rear is much more useful for aliens than ability to enter the UFO through different entrances is for me.

20 turns would be a few to several minutes. I don't know why government would

[moriarty]

Note that these damages are on completely different scale than the Battlescape damages.

yes, I am aware of that.

The main challenge for a Battlescape damage system is that all damage would probably be located in the rear area of UFOs because interceptor is simply chasing the UFO. It seems that UFOs just fly on auto-pilot until the crew realises that they are being attacked and increases speed to outrun the interceptor.
So, a completely mangled rear area of the UFO would be be more probable than mild all around damage that is the result of re-using the Power Source detonation code.

actually,  given the mostly-circular design of UFOs as well as the fact that the air combat window can only be a gross simplification of what's really going on, I'd say that a random damage system is perfectly fine. UFOs use a gravitational propulsion system, they can very well rotate in-flight to fire at you, exposing different sides to incoming fire.

the xcom approach (the original game design) was always to make stuff very much random - that way the player can interpret a lot into it, but always encounters surprises.

oh, and please don't de-rail this thread with the real world weapon discussion, that doesn't lead anywhere.

my table above is a suggestion of in-game mechanics that try to make sense within the game setting. it will have to be playtested, of course. too many holes in UFO walls may be a terrible idea... on the other hand, I think it increases the tactical depth of the game: use overly powerful weapons, and you get less loot. a 3x3 hole in the wall of a medium-sized UFO is perfectly capable of destroying stuff inside the UFO that you want to recover. (the next step would be to tie power source explosions to the power of the shots that hit the UFO... if you want to recover elerium, you better wear it down instead of nuking it).

[Solarius Scorch]

Oh God, these craft weapon descriptions are non-canon and absolutely horrible XD (original X-Com had no craft weapon descriptions). I don't know what the person who wrote them was thinking XD .

Actually, these descriptions were right there in the original game! They just weren't displayed. I discovered them around 1998, at my first attempt to localize the game, and was quite surprised.

As for multiple holes, I am in favour of them, as long as we don't get them every single time a UFO crashes - it would somewhat detract from the gaming convention, where UFOs tend to crash relatively unscathed (like in the UFO TV series, which almost certainly was an important source of inspiration for X-Com). But some chance for them would be nice, preferably depending on air combat factors.

my table above is a suggestion of in-game mechanics that try to make sense within the game setting. it will have to be playtested, of course. too many holes in UFO walls may be a terrible idea... on the other hand, I think it increases the tactical depth of the game: use overly powerful weapons, and you get less loot. a 3x3 hole in the wall of a medium-sized UFO is perfectly capable of destroying stuff inside the UFO that you want to recover. (the next step would be to tie power source explosions to the power of the shots that hit the UFO... if you want to recover elerium, you better wear it down instead of nuking it).

Yep!