Benefits and risks of hull down battle positions

[Bulletpoint]

16 hours ago, Thewood1 said:

Hopefully someone can net it out with my question.

Is the hulldown tank a smaller target than a fully exposed tank?  Wouldn't that make a significant difference in the hit rate on the hulldown tank?

In theory yes, but only at long range. At 600m, it seems WW2 tanks are so accurate that the first shot will generally hit even a target as small as a turret. Whether that matches reality I don't know.

[Drifter Man]

22 hours ago, IICptMillerII said:

It also shows that at point blank range of 600m, ballistics are simulated correctly. The shell being fired is going to hit where the crosshair is placed with a very small degree of deviation.

In CM, this is actually not true - a shot fired at 600 m is not a sure hit. Below is a printout of my gun accuracy tests for the Pz IV, with Regular crew, no modifiers, target Pz IVH fully exposed on flat ground. The probability of hitting with the first shot is around 32% (highlighted). Therefore, there is room for the hull down position to make a difference in the chance of hitting. But that's apparently not happening.

MAIN GUN DATA PzKpfw.IV
Panzer IVG (late) - 75mm L/43 KwK40 [CMBN v4.03]
Range (m)	200	400	600	800	1000	1200	1400
Time to first shot (s)	3.3	4.7	5.9	6.4	6.6	7.0	7.1
Time to second shot (s)	8.6	10.4	11.3	12.0	12.2	12.9	13.1
First shot hit chance		77.8%	29.9%	15.0%	8.6%	5.8%	4.3%
Second shot hit chance			75.8%	52.1%	36.8%	27.1%	21.4%
Panzer IVH (late) - 75mm L/48 KwK40 [CMBN v4.03]
Range (m)	200	400	600	800	1000	1200	1400
Time to first shot (s)	3.4	5.1	6.0	6.8	7.1	7.3	7.2
Time to second shot (s)	8.9	10.5	11.2	11.5	12.3	12.5	13.1
First shot hit chance		81.3%	31.7%	16.0%	9.6%	6.1%	4.1%
Second shot hit chance			78.4%	53.6%	39.3%	28.6%	21.7%
Panzer IVG (late) - 75mm L/43 KwK40 [CMBN v4.03]
First shot trials		10000	13000	11000	11000	11000	11000
First shot hits		7779	3892	1646	951	642	475
First shot hit chance		77.8%	29.9%	15.0%	8.6%	5.8%	4.3%
Second shot trials			10797	10144	10560	10709	10831
Second shot hits			7649	4877	3603	2685	2184
Second shots not taken			2203	856	440	291	169
Second shot hit chance			75.8%	52.1%	36.8%	27.1%	21.4%
Accuracy rating							96
Panzer IVH (late) - 75mm L/48 KwK40 [CMBN v4.03]
First shot trials		10000	13000	11000	11000	11000	11000
First shot hits		8128	4120	1760	1054	674	454
First shot hit chance		81.3%	31.7%	16.0%	9.6%	6.1%	4.1%
Second shot trials			10497	10016	10469	10703	10819
Second shot hits			7684	4916	3793	2853	2211
Second shots not taken			2503	984	531	297	181
Second shot hit chance			78.4%	53.6%	39.3%	28.6%	21.7%
Accuracy rating							100

 

22 hours ago, IICptMillerII said:

I would be interested to see the same test run again at tank combat ranges. That is to say, ranges that are beyond battle sight zero/point blank range. Say, double the distance at 1200m. 

I agree that it would be interesting, but I decided not to dedicate computer time to this. With fewer hits I would probably need to test for much longer to get good statistics. But at some point I might test the probability of the first shot hitting a hull down tank at different ranges and compare.

Edited February 21, 2022 by Drifter Man

[Drifter Man]

(Error - double post)

Edited February 21, 2022 by Drifter Man

[Bulletpoint]

Ok so what you're saying is basically that hull down doesn't make the tank more difficult to hit, despite the turret being a much smaller target... That sounds off.

[Grey_Fox]

4 minutes ago, Bulletpoint said:

Ok so what you're saying is basically that hull down doesn't make the tank more difficult to hit, despite the turret being a much smaller target... That sounds off.

It doesn't make it harder to hit... at point blank range once you already have the spot and the gunner just needs to point the crosshair at it without having to adjust for range.

Edited February 21, 2022 by Grey_Fox

[BletchleyGeek]

Just for the benefit of some readers, "point blank range" means "range with a flat trajectory". That is, the maximum range at which the projectile roughly flies along a straight line towards the target before the forces of gravity and friction with the atmosphere overcome linear acceleration and the trajectory becomes curved. Or in other words, the maximum range at which the gunner can set the gun elevation to zero degrees and be quite certain the shot won't be short. The shot can still miss for other reasons, obviously.

 

As an ESL person who wasn't educated in the terminology I need to remind myself of this all the time when I read these discussions.

Edited February 22, 2022 by BletchleyGeek

[BletchleyGeek]

With this handy trajectory calculator

https://www.omnicalculator.com/physics/trajectory-projectile-motion

one can make their own mind regarding point-blank ranges for World War 2 guns and projectiles. For the German Panzergranate 40, APCR, I get from Google a muzzle velocity of 1,130 m/s. Making a guesstimate that the gun height would be like 2.5 meters, I would say that "point blank range" (for a target in hull down like Cpt. Millers' Abrams is and a firer aiming straight for the mouth of the gun barrel) is about 200 meters, at that distance the height decay of the projectile is about 30 cms (218 yards and 1 foot for the US friends).

Edited February 22, 2022 by BletchleyGeek

[domfluff]

Its worth pointing out that the battlesight is zeroed to a figure, which we believe to be 800m (since this was increased for cold war).

That means that although I do think ballistic calculation isn't entirely the wrong tool to use here, the angle certainly will *not* start at zero degrees - best way to model that is for the shell to lose zero height at 800m (so the trajectory will go up, then down), for the given velocity.

Then it's worth considering both error bars, and the height of the exposed portion of the tank.

This is a good tool to help understand ballistics, but it does need to be used carefully

 

Edited February 22, 2022 by domfluff

[domfluff]

So I make that an angle of about 0.18 degrees, which means at 600m, the shell is at +50cm.

The height of a Panzer IV is 2.68m, with the turret taking about a third (judging by eye) of that, or 0.89m.

Centre of the turret then has 0.46m either side of it. That means the top of the tank is 4cm lower than the "point blank" (which I agree, pedantically, is not the correct term - "point blank" would mean "can hit without using the sights" in this sense), or rather the pre-zeroed position.

CM is also explicitly not a firing range - it's a design principle that there is an assumption that you're involved in full-on combat - so there will be deviation from that point. That'll take the form of a vertical ellipse from this central point, and the size of that ellipse will depend on too many factors to guess at (but you can iterate solutions to get a reasonable idea).

[domfluff]

Obviously that 4cm "miss" doesn't take into account the 7.5cm shell, or that the tank is a 3D object, but again, this kind of tool is useful to get some understanding of the physics involved, but one that needs to be applied carefully to real-world results. Spherical elephants in a vacuum, etc.

[BletchleyGeek]

With the same parameters (1,130 m/s muzzle velocity, 2.5 height of starting location for the projectile), but with an elevation of about 0.37 degrees rather than 0, you get a ballistic trajectory which at about 800m reaches its zenith (at a height of about 5.25m) and hits the ground at about 2,000 meters. At such high speeds, a difference of arc minutes (like 20 arc minutes) is quite significant. But unless we're assuming a height differential of 3 meters between the point of departure of the projectile and the target, what you describe sounds to me like a quite "high and long" shot.

I can totally agree with the statement that it was and is standard procedure to have some "firing solutions" (e.g. gun elevations and ranges) pre-calculated. You don't want to be doing "line search" (which is the procedure I used to figure out the elevation that was the best fit for what you described in your first answer to my post) in combat conditions (tired, scared, under pressure). Definitely not good for clear thinking and problem solving.

Look, from my point of view there is Physics and there are... Unicorns. The former has behaved in the same way since probably a very short time after the Big Bang and hyperinflation ensued, and will probably go on until Boltzmann Brains are a thing. Certainly the relevant part of Physics - Newtonian mechanics - were an approximation of ballistics as good now, as it was in 1944, and as it will be in 2024 (unless the usual caveats apply, that is, the projectiles are really, really tiny, or go really, really fast). Unicorns are a most remarkable phenomenon, known under many names, like phlogiston, aether, mana, etc. It is well known as well that their properties change across time and space depending on the observer. 

I think Physics works, probably because in the Engineering School I got brainwashed or something.

I also think that CMx2 is a reasonable physics simulator for ballistic trajectories and the misnomer that are "external ballistics". 

Judging from your later posts, I think we're in agreement re: Physics. I was wondering after reading the first one.

[Bulletpoint]

11 hours ago, Grey_Fox said:

It doesn't make it harder to hit... at point blank range once you already have the spot and the gunner just needs to point the crosshair at it without having to adjust for range.

Yes, in theory... but reading Drifter Man's findings, it seems even when you have a spot and just need to point the crosshairs at the target, you still miss two thirds of the times.

I understand this is to represent stressful battlefield conditions. But even in battle, I would think that hitting a smaller target is still more difficult than hitting a larger target.

And, if I understand Drifter correctly, in CM, the odds of hitting a small and large target are still the same. That's what I think seems off.

[domfluff]

So from the same calculator, I make that 0.18 degrees, not twice as much. It could probably go a bit lower and flatter than that (this was only a quick guess), and at that inclination doesn't reach as high as 5m.

Trajectory at 0.18:

[Drifter Man]

39 minutes ago, Bulletpoint said:

Yes, in theory... but reading Drifter Man's findings, it seems even when you have a spot and just need to point the crosshairs at the target, you still miss two thirds of the times.

I understand this is to represent stressful battlefield conditions. But even in battle, I would think that hitting a smaller target is still more difficult than hitting a larger target.

And, if I understand Drifter correctly, in CM, the odds of hitting a small and large target are still the same. That's what I think seems off.

Yes - I don't know about tank gun ballistics, I just know that a Pz IV shooting at another, fully exposed Pz IV at 600 meters misses about 68% of its first shots in CM. If the target being hull down changed that to, say, 80%, we would see it in the results - the hull down tank would retain its advantage even when spotting is taken out of the equation. We would see that even if the 3rd and subsequent shots are sure hits. But we don't see that.

However, it is not a direct proof that the hull down tank is not less likely to hit. It is just implied by two series of tests that measured something different. I would have to measure the probability of hitting a hull down target directly.

Edited February 22, 2022 by Drifter Man

[KGBoy]

Berm Drills!

Thank you CptMillr for putting a name to something I thought I had invented for myself while playing CM1. I always felt guilty about being 'gamey' for it but now I see I am not.  Of course it works a bit differnetly in the game in that the hunt command will make a shooting war start and lose the reverse. It works really well in pairs. Losing a tank is one thing but not killing the thing that needs killing at the same time is so much worse!

 

As usual Drifterman a very well reasoned response.

[Pandur]

On 2/10/2022 at 7:15 AM, MikeyD said:

Perhaps its my imagination, but it seems if you use the 'hull down' movement command instead of doing it on your own the opposing tank's first round will tend to go high and the second impact the ground in front of you before finding the range. The game seems to have built-in the initial rounds struggling to find their mark. If you move to the same position in the normal manner the chance on seen a ground impact ahead of you is negligible.

 

Wait what? How does that make sense? Do you get an artificial "protection bonus" from the use of hull down command or what does that mean?

I was under the impression that hull down´s are created equal. If i use the command or if i drive to the same spot myself, same result, or so i thought? But that is not so?

 

I dont like the hull down command, on easy to see positions it is as easy to drive there myself, on very tricky LOS situation where it is not clear where a position will be, the hull down command can spell death to your vehicle as it just keeps driving and driving never finding a position. So in my eye the HD command is useless(at least i never use it), but if it has a bonus protection gimmick built in, maybe i should get around to us it? 

[Rake]

On 4/29/2022 at 3:53 AM, Pandur said:

 

Wait what? How does that make sense? Do you get an artificial "protection bonus" from the use of hull down command or what does that mean?

I was under the impression that hull down´s are created equal. If i use the command or if i drive to the same spot myself, same result, or so i thought? But that is not so?

 

I dont like the hull down command, on easy to see positions it is as easy to drive there myself, on very tricky LOS situation where it is not clear where a position will be, the hull down command can spell death to your vehicle as it just keeps driving and driving never finding a position. So in my eye the HD command is useless(at least i never use it), but if it has a bonus protection gimmick built in, maybe i should get around to us it? 

This!

@Bil Hardenberger, in his blog, has recommended using other move commands to a potential hull down location, changing the last waypoint to "Hunt" upon verification that you are hull down, or partial hull down:

https://battledrill.blogspot.com/2013/09/movement-technique-005-hull-down.html

And, IIRC, I believe I've seen him mention that he doesn't (or only rarely) use the Hull Down command.

If there is indeed artificial protection from using the Hull Down command, I suppose I should start trying it again.  I'd given up on the command after several tanks stopped without achieving LOS to a targeted area, or even worse, kept driving across the berm and met their fate.

So, is this "Protection Bonus" a real thing?

 

 

Edited April 30, 2022 by Rake

[chuckdyke]

29 minutes ago, Rake said:

So, is this "Protection Bonus" a real thing?

I think once the AI calculates the hit it must hit the fighting compartment. All the other parts are behind hard cover. Also it is harder to get an LOS. I rarely use the Hull-Down myself. 

[Erwin]

On 4/29/2022 at 1:53 AM, Pandur said:

I was under the impression that hull down´s are created equal. If i use the command or if i drive to the same spot myself, same result, or so i thought? But that is not so?

That is my understanding as well.  But as others have mentioned, I never use the "auto hull-down command" as it can give undesirable results.  Experience makes it easy to do it manually.

[Pandur]

What i am trying to find out is if there is indeed an artificial protection bonus you get with the HD movement command or not.

I would have never thought about that, but from what MikeyD wrote, it seems that could be a reality?

[Pelican Pal]

You would have to run tests since Charles isn't going to reveal the inner-workings of the code and I strongly suspect none of the beta testers get that info either.

What most of this comes down to is that, regardless of what would happen in real life, CM is a game whose core code is 13-14 years old (if not older). Its closer in time to the release of CM:BO than today. That leaves room for meta-gaming outcomes based on how the code is biased. Although even a brand-new game will be biased by the programmers assumptions and code limitations.

----

The logic behind movement commands having an impact to the combat cycle isn't totally outrageous since it would be an easy way to add in abstracted inputs. Although if I had to put money down I would say it doesn't.

[Blazing 88's]

Thanks to Hapless this has helped me immensely. Very useful (the second method).

Combat Mission Basics: Vehicle Movement (timestamped to Hulldown)

Edited April 30, 2022 by Blazing 88's

[KGBoy]

The begging question for me is: If Hull Down movement is near pointless what would you replace it with?

I am certainly willing to be edified here but off the top I would like to see a Slow Hunt. I use Slow but I wish it had a hunt kicker so that it would stop when having spotted something.  I have never seen it stop and shoot but always rolls to command point while shooting.

[Combatintman]

5 hours ago, KGBoy said:

The begging question for me is: If Hull Down movement is near pointless what would you replace it with?

I am certainly willing to be edified here but off the top I would like to see a Slow Hunt. I use Slow but I wish it had a hunt kicker so that it would stop when having spotted something.  I have never seen it stop and shoot but always rolls to command point while shooting.

It is a matter of taste, perception and implementation.  The Hull Down command in CMx1 was apparently quite good, I don't remember the intricasies myself but it seemed to work pretty much as designed; however, CMx2 is a lot more detailed in its modelling which makes things like hunt and hull down more tricky to implement in a way that satisfied players.  Some very experienced and highly skilled players such as @Bil Hardenberger eschew the Hull Down command in favour of using a series of other commands to get their unit/vehicle to a point that they have identified is Hull Down in relation to the direction the unit/vehicle will face or hull down in relation to where the enemy might be pointing a day ruining weapon system.  I am not a good player and rarely play the game other than testing scenarios so my comments in relation to whether Hunt-Slow-Pause combinations work better than Hull Down should be taken in that context.  My preference is to use a combination system rather than Hull Down but. I have seen Hull Down do the job on many occasions.

The sum of the parts is that it is not a case of coming up with a 'Don't Get Shot' (or whatever it is going to be called) command to replace Hull Down it is more one of deciding how much you are bothered by your troops getting zapped and working out whether Hull Down or another sequence of the available commands is the best solution to assuage your concerns.

[Bil Hardenberger]

On 4/30/2022 at 8:37 AM, Rake said:

This!

@Bil Hardenberger, in his blog, has recommended using other move commands to a potential hull down location, changing the last waypoint to "Hunt" upon verification that you are hull down, or partial hull down:

https://battledrill.blogspot.com/2013/09/movement-technique-005-hull-down.html

And, IIRC, I believe I've seen him mention that he doesn't (or only rarely) use the Hull Down command.

If there is indeed artificial protection from using the Hull Down command, I suppose I should start trying it again.  I'd given up on the command after several tanks stopped without achieving LOS to a targeted area, or even worse, kept driving across the berm and met their fate.

So, is this "Protection Bonus" a real thing?

 

 

The advantages with a hull down tank are with spotting... and probably the to-hit chance as well.  I will always use hulldown when possible because I have too many examples of hulldown tanks dominating their side of a map and never being spotted (see any of my AARs for examples).

As far as the hulldown commmand goes.. I have tried it out a few times, but I think it's a shortcut that I don't need, so I never use it, preferring to enter hulldown manually, I just feel more comfortable have the control of where my tank comes to a halt. 

It isn't the way you get into hulldown that is important, though, its that you ARE hulldown... if you are comfortable with the command, then by all means use it.

Bil