German tank vulnerability

[Other Means]

In CMx1, positional angle was used horizontally directly, and vertically only for the relative height of the units, but not tilting of the target.

Unless I hear otherwise I'll assume it's unchanged.

That wasn't the case in CM1. Any angle on the AFV was added to the calculation of the armour thickness.

One gamey trick I always enjoyed was situating Churchill Xs on high angle reverse slopes. I bounced a Tiger I shell off the glacis at 50m once. I'd have loved to see my friends face.

[Elmar Bijlsma]

Top hits gun/vehicle to vehicle were not modeled in CMx1 regardless of what elevation was involved.

It most certainly was.

[SleeStak]

No, you can't do high school math on the angles when it comes to WW2 kinetic rounds armour penetration.

The high angle increases the resistance much more than you just gave it credit for. Unless you are willing to use a formula that allows you to actually compute penetration at any angle you are closer to the truth using the 60 degrees number than the 30 degrees number when looking at a 47 degrees plate.

The penetration CMAK gives the 75mm L/48 in a Pz IV at 60 degrees and 500m is 48mm and that is less than the 64mm of that plate.

Plus, if the target did not face the shooter directly, any resulting horizontal angle from that will add (not be added directly) to the armour plate angle.

I could dig out some old programs to get an actual 47 degree number for L/48 penetration (not sure I ever put that gun in) but I'm sure it will be right around the thickness of this plate at 500mm. If there's any positional angle you are right out, statistically.

You couldn't point me in the direction of finding the equation that would allow us to calc penetration values at angles, could you? I'd love to have that formula. The results of the AAR surprised me (I would have expected the PzIVs to have more luck penetrating the Shermans at 500m) and I'd like to have a better understanding of how all this works. I'm all for Shermans surviving whatever hits they should survive, I just didn't think they should have survived multiple hits at that range from that gun.

[Redwolf]

This is not CMx1 Redwolf.

That why I asked whether you got confirmation of a top hit on a CMx2 Tiger.

[Redwolf]

You couldn't point me in the direction of finding the equation that would allow us to calc penetration values at angles, could you? I'd love to have that formula. The results of the AAR surprised me (I would have expected the PzIVs to have more luck penetrating the Shermans at 500m) and I'd like to have a better understanding of how all this works. I'm all for Shermans surviving whatever hits they should survive, I just didn't think they should have survived multiple hits at that range from that gun.

I use the stuff from Rexford's book. Unfortunately that might be difficult to get ahold of now. I should probably slam the code into a website where people can fill out fields and get answers but I don't remember how much I did.

I wish somebody could contact Rexford's next of kin and ask for permission to distribute copies of this book.

Understanding wise it is easy: the projectile has a diameter, it is not point-shaped. That means that, on impact, the outer parts of the projectile will steer it out of the armour to a certain degree. So if there is an big angle the angle will be bigger from the projectile's perspective. Line-of-sight armour thickness along the original path does not apply because it doesn't stay on that path.

People then shaped the projectile differently so that it didn't present a flat side but that leads to other problems that also damage angle performance or all performance and requires an aerodynamic cap etc.

This is different for modern SABOT rounds which are very slim and very hard and are pretty much point-shaped and hence don't steer out.

[Redwolf]

It most certainly was.

I will paypal $20 to the first person who can show a screenshot of a gun (including vehicle main gun) hit on the top armour of an AFV in CMx1.

They had top hits from mortars, hand grenades and molotovs but not from AP shots.

[Redwolf]

That wasn't the case in CM1. Any angle on the AFV was added to the calculation of the armour thickness.

One gamey trick I always enjoyed was situating Churchill Xs on high angle reverse slopes. I bounced a Tiger I shell off the glacis at 50m once. I'd have loved to see my friends face.

After American Idol I'll do a quick test but I remember that the display about kill chance did not change with vehicle tilt.

If the Churchill is overall at a higher elevation, yes you will get the angle increase out of that.

[Elmar Bijlsma]

I will paypal $20 to the first person who can show a screenshot of a gun (including vehicle main gun) hit on the top armour of an AFV in CMx1.

They had top hits from mortars, hand grenades and molotovs but not from AP shots.

The mighty 2pdr smacking around a Tiger

http://img94.imageshack.us/i/payup.jpg/

Result with vehicles would be same.

*edit*

You are correct that the kill/penetration likelihood information doesn't change. The results however, do.

[Redwolf]

Pm me your paypal address, or physical beer address or somefink.

[Elmar Bijlsma]

Nah, I don't think that will be necessary.

It's just a discussion on a forum where I happened to know the result of the challenge beforehand. I don't think money should change hands over something so trivial.

But thank you.

[Redwolf]

Allright, I'll be sure to tip some pretty waitress extra or somefink.

Hmmm, so if the kill chance display didn't change, not noticing the top kill opportunity, that makes the other experiment kinda moot, does it? The kill chance display might not know that the angle on a tilted angle changes even if the armour penetration mechanism does.

[Battlefront.com]

One of the great things about the way CMx2 handles armor detailing is that we don't care about anything after the data is put in. It's all handled directly and without ambiguity by the ballistics modeling. There's no situation that doesn't have a direct, quantifiable, situationally specific result that should (in theory) conform with historical reality. Top hit, lower hull hit, oblique road wheel hit, whatever... it's all in there.

Note that the downside of this is Charles has to put in a TON of data for each model, which itself is extremely detailed and prepped by Dan. But the workload is up front and it's well worth it.

Steve

[Redwolf]

So does it have hits with horizontal (positional, not plate) angles greater than 45?

For example, target faces you but not completely, can you hit that target's side at 85 degrees or so?

[Gromit]

Redwolf the only reason something wouldn't be simulated correctly from a ballistic point-of-view would be if Dan or Charles input an erroneous piece of data (transposition, whatever) for a given tank or other vehicle (kind of like the Tiger TC facing the wrong way except on a ballistic level instead of spotting) or incorrect data on a tank to begin with. I would surmise they work with blueprints or the like as do Dragon Models and all the other scale model people these days (less errors on their end with 3D too btw).

Essentially, the CMx2 engine recreates an exact 3D replica of the tank in question, that shoots ballistically correct rounds under earth physics conditions. All the plates of armor are modeled on the 3D wireframe exactly where they were placed on the real tank. All the internal systems are modeled with a location and can therefore be hit by rounds and taken out.

So, as Steve said, the beauty of the "engineered solution" is that once you have done your homework and figured out how your going to calculate penetration factors and create all the algorithms necessary to support them for each and every kind of round, along with entering all the data for each model, the results should be (barring errors in data) portrayed in the game correctly, with some other outside factors of wind, etc. in there as well.

It's waaaaay better of a system and not really apples-to-apples comparable with CMx1's engine in my estimation. I think that's where we just need to wait and see despite our first inclination to compare it to what came before (which is just human nature, we do it all day long without even realizing it).

[Battlefront.com]

Exactly what Gromit said The old CMx1 system was "designed for effect" so if we didn't design something we didn't get the effect. In CMx2 everything is "engineered" so there is no effect to be designed for. Whatever situation comes up is handled automatically by checking the intersecting vector relative to whatever was hit. This is probably one reason why the M4A3's appear to be a bit more survivable from PzIV hits than might have been the case in previous CM games.

Steve

[Gryphonne]

Top hits gun/vehicle to vehicle were not modeled in CMx1 regardless of what elevation was involved.

Not sure whether that changed now. Did the new armour penetration message say?

I think top armour is now modelled. I've just tested a scenario (granted, not really reliable) by placing an Ambrams on a slope with a BMP-2 positioned on an opposite slope. This way the BMP could fire "down" on the Abrams at 90 degrees (you can place vehicle on very steep slopes by positioning them on the map first and afterwards changing elevation data). The result was that the Abrams was knocked out each and every time by either the BMP-2 autocannon or missile hitting it from the top. Even an RPG would suffice here. Something that I don't *think* would happen as often from a horizontal front aspect anyway.

[Redwolf]

Essentially, the CMx2 engine recreates an exact 3D replica of the tank in question, that shoots ballistically correct rounds under earth physics conditions. All the plates of armor are modeled on the 3D wireframe exactly where they were placed on the real tank.

Sure, but the question I raised is about the hit probability model, not the 3D or armour model.

Anyone knows the answer?

[Elmar Bijlsma]

Uhm, still seems like you are misunderstanding things, Redwolf. There is no hit probability model.

A gun is no longer fired at a target like in CMx, where a hit or miss was determined at the moment of firing, no matter what the target gets up to between shot and impact.

A projectile is now fired along a certain path and it will hit whatever is in it's path, be it a tree, wall or armour, whether that front, side, top or bottom.

So the only "hit probability" is in the path the projectile is given when fired. The rest is all simulated physics. So yes, it could very well hit that side plate.

[Elmar Bijlsma]

On a somewhat related note there was this CMSF thread that touches upon the joys of the new damage model:

http://www.battlefront.com/community/showthread.php?p=928706#post928706

For those who can't be bothered to click the link, a Javelin drops down on a T-72, hits the roof mounted MG instead. MG wrecked, tank fine. Oh, and there was the mysterious track damage consolation prize, naturally.

[scottie]

Note that the downside of this is Charles has to put in a TON of data for each model, which itself is extremely detailed and prepped by Dan. But the workload is up front and it's well worth it.

Steve

As good a reason as any to have detailed hit text back in , so we can see the hard work you guys went to which would otherwise be hidden away.

[Rocky Balboa]

So the only "hit probability" is in the path the projectile is given when fired. The rest is all simulated physics. So yes, it could very well hit that side plate.

Now that CMx2 has made the jump to a temperate environment, it will be interesting to see how environmental factors (rain, ice, snow, mud) will affect path and penetration.

How does heavy wind/rain affect projectile path? Will snow/ice on surfaces cause less penetrations for lower velocity projectiles? Inquiring minds want to know ....

[Sergei]

Sure, but the question I raised is about the hit probability model, not the 3D or armour model.

Anyone knows the answer?

From watching how gunners behave in CMSF I think it goes something like this:

a) the gunner aims the gun somewhere around the visible part of the enemy, the exact aim point varies just slightly between shots but usually near the center of visible gravity

then the shot is fired, there is some more or less random scatter depending on muzzle velocity, range, wind and so on

c) the shell may hit one or more things on its path, it can also change its course if it hits something, also APFSDS can penetrate all through its target and then hit another target behind it

I remember one test range with SPG-9s firing down lanes separated by tall walls at MBTs, in heavy crosswinds. The shots were very inaccurate in general, but I fondly remember one shot that was taken by the wind across two firing lanes, accidentally hitting the gun barrel of the tank on that lane - even though the firing unit had absolutely no LOS to it! It very clearly showed that there are no hit probabilities in the sense that they're in CMx1.

In yet another firing range test, a Syrian AT-14 missile aimed at a Humvee flew safely right beneath it, because it approached it at precisely the right altitude not to hit either ground or the bottom - obviously a one in a million shot, but I looked at it from every angle and yep there was enough clearance!

I have also seen countless rockets swoosh harmlessly underneath a BRDM-2 situated at a hill top...

[WineCape]

Nah, I don't think that will be necessary.

It's just a discussion on a forum where I happened to know the result of the challenge beforehand. I don't think money should change hands over something so trivial.

But thank you.

This, almost, deserves a case of wine.

[Sergei]

Now that CMx2 has made the jump to a temperate environment, it will be interesting to see how environmental factors (rain, ice, snow, mud) will affect path and penetration.

How does heavy wind/rain affect projectile path? Will snow/ice on surfaces cause less penetrations for lower velocity projectiles? Inquiring minds want to know ....

Wind, as my previous post pointed out, already changed the paths of shells in CMSF, especially those that have little kinetic energy such as rockets.

As to rain, I doubt it would make a difference. Perhaps it would increase the scatter of bullets at long ranges? For bigger shells, though, the effect of rain drops would be just as marginal as fog is for bullets.

Snow or ice does very little to provide cover unless there is literally a ton of the stuff. It takes several meters of packed snow to provide cover from rifle bullets alone. A tank with enough snow and ice on it to provide additional cover wouldn't be operable by any means! A more important weather effect on penetration is the temperature of the gun and the munitions. A 'hot' grenade may overshoot whereas a 'cold' grenade may undershoot the target, because the propellant doesn't react in the determined time. Which is why you shouldn't first fire a bunch of shots until the gun breach is hot, then load another one and leave it waiting.

[Battlefront.com]

Redwolf,

I see you're still stuck a bit in the CMx1 mode of doing things There is no "hit probability" either. As Elmar and Sergei point out, something is fired and it's trajectory is traced exactly as it is shown on screen. Everything that should go into that trajectory, such as aim point, accuracy, velocity, drop, wind error, etc. is taken into account. Wherever the round hits is where it hits. If it hits the edge of a PzIV's fender... THAT is what it hits. There's no calculation like "well, the probability is it would strike the upper hull armor" because that is not what the round hit. Period.

What happens after that is based on the effect that particular round, with whatever properties it had at the time of the hit, would have on whatever was hit. In the case of striking the fender it would likely be simulated to pass through it and strike the armor directly behind it without much appreciable difference than if it hit that armor straight on (I can't say for sure because that's an extremely technical question). The strike against that armor happens because that's where the trajectory would take it. There's no probability because the game knows EXACTLY where it is.

After striking the armor the game figures out what happens. Penetration? Well, that depends on all the variables being carefully calculated. No probability here either, except in the form of variables within the equations where appropriate. Assuming there is penetration then damage is assessed based on what the round hits and what sort of physics are involved. In theory it could pass through and out the other side (happens to Halftracks quite frequently, for example) and impact something else.

It's all physics, not dice rolling. Which means we have 100% of our bases covered 100% of the time with 0% extra work after the initial modeling.

Steve