Long and Short rounds

[carll11]

So, I wanted to wait and play enough in all environments before I sounded off on this topic.
To be frank, if there were the number of long, short, wide arty rounds/airstrikes in Vietnam that I have seen in the game, I wouldn't be here, really, I wouldn't have made my first 6 mos intact.


So, I assume theres a recon value of some type calculated. How many observers?...how far away? Are they in the TOE for the arty? do they have a radio?

Since non American units generally dont have ANY radios I assume there has to be an intrinsic or weighted inset calculated value for their observation...I mean they DID have radios in all TOES in Vietnam maybe not as many as the US etc..

Airstrikes, if a unit has no radio?

It seems I have missed the bus re; this latest patch thats been handed off, but I beg you to lower or modify lower the incidents or chances for FF in this context.

[berto]

Here are the pertinent AAI parameters:

Code: Select all

rober@Rob10rto ~/cslint
$ ./csaiprpt.pl -g vn -defaults -side -nation -if_spotted_scatter_prob -if_unspotted_scatter_prob -if_spotted_scatters -if_unspotted_scatters -f init.ai

init.ai

d                                               0 100   1   2
s  0 A                                         -1  -1  -1  -1
s  1 B                                         -1  -1  -1  -1
n  0 XPeoplesRepublicOfChinaNation              9  86   1   2
n  8 XFranceNation                              8  60   1   2
n 10 XUnitedStatesOfAmericaNation               8  55   1   2
n 11 XRepublicOfVietnamNation                  10  65   1   2
n 12 XSouthKoreaNation                          9  66   1   2
n 13 XLaosNation                                8  53   1   2
n 17 XNewZealandNation                          8  52   1   2
n 19 XAustraliaNation                           8  55   1   2
n 21 XPeoplesRepublicOfVietnamNation            9  70   1   2
n 49 XCambodiaNation                            8  53   1   2
n 50 XThailandNation                            8  52   1   2

You are free experiment, to modify those AAI parameters in the init.ai file. But in order to bypass encryption, where by default the game uses the encrypted init.aix, you would need to run the game with the -X NoEncryption option. To do that, in Windows Explorer:

• Right click the Vietnam.exe frontend EXE.
• Select Create Shortcut.
• (Right click on 'Vietnam - Shortcut, select Rename as you wish.)
• Right click on that shortcut.
• Select Properties.
• In the Target field, after the ending ", append: -X
• Select OK to exit (and save).
• (Copy-paste that shortcut to the desktop etc., as you wish.)

If all goes well, if you launch the game using that new shortcut, the game engine will reference your modified, and unencrypted, init.ai.

So instead of 8 and 55 for the US, you might try cutting one or the other or both in half, to 4 and 27, say. Or maybe a bigger reduction to the 55, so 4 and 15, say. Play with different values, experiment. We welcome your input as to what seems "right".

(We might then share your init.ai modifications with the rest of the players in an unofficial v1.21 data fix patch posted here at the Forum.)

Good luck.

[berto]

Incidentally, about the 2 value for the if_unspotted_scatters:

2 hexes is the farthest away unspotted Indirect Fire might drift. But the way the code algorithm works, more likely any drift would be just one hex away; and indeed, the fire might "drift" back onto the central targeted hex, i.e., effectively no drift. It's complicated! Just keep in mind: Scattering fully 2 hexes away is unlikely.

[carll11]

So what it appears you're saying is, every shot may scatter, no matter the observation of the target hex?

The 8 and 55 dictate scatter, these 'odds' dont get lowered or increased due to the observer/spotter etc.?

Ex; a Korean inf. unit observes ( is a spotter) for a hex with enemy within, a US arty unit fires on the hex and the odds of it hitting are no better than if it was an American unit with a radio OR a arty helo spotter? Or a Korean arty unit firing?

[carll11]

OK,thank you..... I went ahead and created the shortcut and added the -X. I made some adjustments to the 55 , 56 slots.....the game is running via the new shortcut.....is there any sign that I am using the edited init.ai file I can see to be sure?

[berto]

So what it appears you're saying is, every shot may scatter, no matter the observation of the target hex?

No. The 1 or 2 scatter is only if a shot fails the prob test.

The 8 and 55 dictate scatter, these 'odds' dont get lowered or increased due to the observer/spotter etc.?

Apart from spotted vs. unspotted, it is heavily abstracted. Spotted vs. Unspotted -- that is the key difference.

Ex; a Korean inf. unit observes ( is a spotter) for a hex with enemy within, a US arty unit fires on the hex and the odds of it hitting are no better than if it was an American unit with a radio OR a arty helo spotter? Or a Korean arty unit firing?

These were best guesstimates at the time. They are all subject to tweaking.

[berto]

OK,thank you..... I went ahead and created the shortcut and added the -X. I made some adjustments to the 55 , 56 slots.....the game is running via the new shortcut.....is there any sign that I am using the edited init.ai file I can see to be sure?

Try Alt+F10. That will do an AAI data dump to dialog box. Look for your adjusted values in current values. You can probably figure it out.

[berto]

More AAI parameters to look at, possibly experiment with:

Code: Select all

rober@Rob10rto ~/cslint
$ ./csaiprpt.pl -g vn -defaults -side -nation -airstrike_spotted_scatter_prob -airstrike_unspotted_scatter_prob -airstrike_spotted_scatters -airstrike_unspotted_scatters -f init.ai

init.ai

d                                              25  80   2   4
s  0 A                                         -1  -1  -1  -1
s  1 B                                         -1  -1  -1  -1
n  0 XPeoplesRepublicOfChinaNation             25  80   2   4
n  8 XFranceNation                             25  80   2   4
n 10 XUnitedStatesOfAmericaNation              25  80   2   4
n 11 XRepublicOfVietnamNation                  25  80   2   4
n 12 XSouthKoreaNation                         25  80   2   4
n 13 XLaosNation                               25  80   2   4
n 17 XNewZealandNation                         25  80   2   4
n 19 XAustraliaNation                          25  80   2   4
n 21 XPeoplesRepublicOfVietnamNation           25  80   2   4
n 49 XCambodiaNation                           25  80   2   4
n 50 XThailandNation                           25  80   2   4

The code for airstrikes, and possible airstrike scatter, is quite complicated. For example, it takes into account whether the attacking aircraft have the XFastMover flag and/or fire rockets, whether they have the XFAC (Forward Air Control) attribute, etc. If an aircraft with FAC attacks a spotted hex, in theory -- and in practice, we hope! -- the airstrike should not scatter.

Don't be too alarmed by the, seemingly high, 2 & 4 scatters #s. They are the number of steps in a random walk algorithm, where the steps might be outward from the target hex, but can easily be backward steps towards the center. So a 4-step random walk might in fact end up just 1 hex away, possibly even walk back to the center (the intended target hex). The random walk algorithm allows for very wide scattering, but in practice tends to favor slight scatter over wide scatter.

Here, too, we invite you to experiment with these values and to give us your feedback.

[carll11]

OK, thank you berto, the dump worked.

I am playing around with parameters.

[berto]

Good luck!

[carll11]

Whats the deal on the not authorized airstrikes thing...?

[Jason Petho]

Just like artillery, airstrikes needed to have approval (nature of the Vietnam War) from up the chain.

In some cases the authorization was denied for a variety of reasons.

[berto]

In the (American period) Vietnam War, arty strikes and airstrikes (especially the latter) usually needed to be cleared beforehand up the chain of command, often to the political authorities, such as mayor or district/province chief. The occasional "not authorized" or "denied" is to model that possibility.

(Note that if not blocked due to "denied", arty strikes or airstrikes against "habitat hexes" -- Village, Suburb, City -- will usually incur an EP penalty, larger if the target hex is not occupied by enemy units. Unless, in the .lua script, some or all of the map has been declared a free-fire zone. There are a number of scenarios where the entire map is free-fire, hence no IF or airstrike penalties. But in most, the EP penalties pertain.)

Thus, the game models political considerations, not just combat considerations. These were counterinsurgencies and highly political conflicts, after all. ("Winning hearts and minds.")

The chance of "denied" happening is governed by the AAI parameters

---

Code: Select all

rober@Rob10rto ~/cslint
$ ./csaiprpt.pl -g vn -defaults -have -side -nation -indirect_fire_denied_prob -airstrike_denied_prob -f init.ai

init.ai

d                                               0   0
s  0 A                                         -1  -1
s  1 B                                         -1  -1
n  0 XPeoplesRepublicOfChinaNation              5   0
n  8 XFranceNation                              5  10
n 10 XUnitedStatesOfAmericaNation              10  20
n 11 XRepublicOfVietnamNation                   2  10
n 12 XSouthKoreaNation                          5  15
n 13 XLaosNation                                5  15
n 17 XNewZealandNation                          5  15
n 19 XAustraliaNation                           5  15
n 21 XPeoplesRepublicOfVietnamNation            0   0
n 49 XCambodiaNation                            2  10
n 50 XThailandNation                            0   0

---

You can modify these in a scenario .ai file, but it is usually easier to tweak them in a scenario .lua file.

Note where the default values have the "trigger happy" Americans especially subject to possible arty strike or airstrike "denied". While the VC/NVA can fire at will!

[berto]

As I have read, during the Tet '68 Battle of Saigon, the Americans were severely constrained not to airstrike within Saigon city limits. Possibly their heavy artillery was kept on a short leash also.

This will be reflected in the AAI parameters for that scenario. Possibly others, though maybe not the Hue scenarios (or will be mitigated), where in the real life battle much of Hue was destroyed.

[Feltan]

Interesting discussion. A few points to add in:

1. Artillery (for the US) is often called "on-demand" and begins with "spotting rounds." A spotting round being a single gun from an artillery battery lobbing a shell as close as it can to the designated target. Spotting rounds are corrected by a forward observer, and the next spotting round should be closer to the target. I believe the standard is to get a spotting round on target within three corrections.

2. When a spotting round lands with-in 50 meters of the target, the battery will "fire-for-effect." All guns trained on the same azimuth and elevation as the spotting gun, and with the same charge for the shell. Usually, one round from each gun in a single volley will complete the fire mission.

3. This process takes a few minutes ... sometimes more than a few. A poor forward observer can walk spotting rounds all around a target (over or under correct) before a firing solution is achieved (which also creates some lively and colorful radio chatter).

4. Not all nations follow this paradigm. Some simply use map locations to calculate range and fire-for-effect with an allowance for Kentucky windage. Others heavily use pre-planned fires; in order and on a time table.

5. A spotting round being off by a few hundred meters is not unheard of. There is a fair amount of human error possible. However, fire-for-effect (for the US) would rarely be off by greater than 100-200 meters unless something very odd is going on. My guess is that most are <100 meters off center of target; many are spot on target. (My experience, please weigh-in if you have different observations.)

So a question: How long is a game turn? A typical fire mission is <5-10 minutes (although this varies); if not denied or cancelled, 10 - 20 minutes would seem like the outer reasonable limit. Uncrating ammunition, or other high priority targets can delay things. If a game turn is, say, somewhere around 20 minutes or so, multiple fire-for-effect missions from the same/different battery are quite possible. A repeat fire-for-effect mission is also a common request/practice, so mutiple volleys are possible given the length of a game turn.

This all might be too difficult or detailed to model in a game of this scale. But the scatter issue is real. The OP is correct in my opinion; a US fire-for-effect mission would not be expected to drift >250 meters (one hex)... that would be very odd. A one-hex drift is, in my opinion, occasionally OK simple because not all targets are going to be dead center in hex, and a 100 meter drift could easily be in the next hex -- a limitation of the scale and model. A two hex drift (250-500 meters) mean some rare and gross error has occurred.

Air strikes are different kettle of fish so I won't get into them here.

Regards,
Feltan

[berto]

Don't be too alarmed by the, seemingly high, 2 & 4 scatters #s. They are the number of steps in a random walk algorithm, where the steps might be outward from the target hex, but can easily be backward steps towards the center. So a 4-step random walk might in fact end up just 1 hex away, possibly even walk back to the center (the intended target hex). The random walk algorithm allows for very wide scattering, but in practice tends to favor slight scatter over wide scatter.

I won't diagram or explain the math here, much less show the code (one of the game's "secret sauces"). But bear in mind the highlighted portion.

Ah, the duration in minutes of the "typical" game turn: controversial topic, that. Let's just say that the "typical" game turn would usually give sufficient time for, as you describe it, the Americans to spot-and-correct. That, and your observations, suggest that the American

Code: Select all

rober@Rob10rto ~/cslint
$ ./csaiprpt.pl -g vn -defaults -side -nation -if_spotted_scatter_prob -if_unspotted_scatter_prob -if_spotted_scatters -if_unspotted_scatters -f init.ai

...
n 10 XUnitedStatesOfAmericaNation               8  55   1   2
...

8% if_spotted_scatter_prob might be too high, while the if_spotted_scatters of 1 is "right" (because if 0, there would never be any scatter at all).

I think the if_unspotted_scatters of 2 is about right, but what would you suggest for the if_unspotted_scatter_prob? (Note that with the random walk algorithm used, there is a real chance the strike will walk back to the center, so the 55 is in effect actually lower than that, more like 45 percent.)

[Feltan]

berto,

I used to code for a living. I don't do that anymore. I also don't code games because it kind of ruins the fun of playing them, for me anyway.

I'll galdly leave the coding up to you without argument or objection. That, and I'll let you tussle with the sometimes very difficult choices involved with modelling certain activities. You can do both with my extreme thanks.

That being said, I do have expectation for final outcomes. With regard to artillery fire; given chances for a fire mission to achieve the following final results, modified somewhat for game semantics:

US Forces:
Fire-for-effect on time in target hex: 80%
Scatter one hex: 5%
Scatter two or more hexes: 1%
Cancelled, rejected or not fired: 10%
Delayed one or more turns: 4%

Non-US Forces:
Fire-for-effect on time in target hex: 50%
Scatter one hex: 25%
Scatter two or more hexes: 10%
Cancelled, rejected or not fired: 10%
Delayed one or more turns: 5%

Just a few notes:

I am not being jingoistic favoring the US. Most international observers rate US artillery a cut above the rest, and most NATO counties have adopted the Fire Direction Center (FDC) methodology that the US uses. However, in WWII and during the timeframe of Vietnam, the FDC was not widely practiced outside US forces due to communication and mapping limitations. It makes a huge difference. The most common alternative is point-of-reference aiming on a battery by battery basis.

The Cancelled, rejected or not fired covers a multitude of situations. As has been stated above, especially in Vietnam, political concerns were sometimes paramount. It also covers something not previously mentioned, deconflicting airspace with rotary and fixed wing aircraft; missions get cancelled or delayed to avoid having shells in mid-air during close-by aircraft missions. This grouping would also cover supply chain issues like readying ammunition, communication outages (always an issue), artillery battery displacement and movement, other fire priorities, etc.

The percentages above are my opinion, not backed up with quantitative data but with some validity from practical experience.

Regards,
Feltan

[berto]

Thanks so much. Informed opinion, even best guesstimates, are always welcome. I expect we might be posting an unofficial beta patch, data only, within the next few weeks. (With an official, more substantial data and code patch planned for later in the summer.)

[carll11]

Thx Feltan, you said a lot and very well, that I was preparing to say once I cleared some time to play and get to the site again.

A few random points if I may;

A huge preponderance of Arty Officers in the Korean army for example being somewhere over 80% that went to SVN had been to Ft. Sill arty school, which is and may still be the preeminent arty school globally and was and were teaching ( as Feltan alludes) the FAC<>FO<>FDC style call for fire mechanics,
Due to turn over in the ARVN I'd say the avg. from year 64-65+ would be on the order of 70%+ of their off. being Ft.Sill trained. Now their actual Ops in the field would vary naturally as in how efficient arvn units were; Rangers, Paras and Marines being the most efficient of the lot.

If I recall and I still have my circa 1970 FMs 3-90 call for fire and 21-26 land nav. Books around here somewhere a grid sq. on a 1:50K map is 1KM squared meaning there were 4 games hexes approx. per grid sq., and, as Felton alludes, being off by a quarter grid sq. with even your initial spotting round is, well, a lot, a real lot Ergo; with a 2 hex ‘drift’, you could wind up being off by 500 meters, that’s phenomenally atrocious.

RE: ROE ( Rules of Engagement) etc. in almost all circumstances I can remember, and having spent 6 mo.s of my 18 months as an RTO, we knew before hand if we were patrolling or operating in a free fire zone.
In some cases ( not many) yes, absolutely, before we engaged we called the Bn. Ops, our S2 would make the call on the spot, yes go hostile if fired upon, calling for fire? Or an Airstrike? The unit Co. would request fires, its on him, if we called in a tube/airstrike on a village were taking fire from, and we generated civvie casualties, well, this a) would not be unusual unfortunately and b) his responsibility. IOW, once we took fire, pretty much all bets are off. I am not speaking to built up areas, suburbs+ etc, since that fighting was rare and, yes, it would take a Brigade G2 to make that call. But villages etc. no.
Of course reconning by fire was usually a co. thing, mortars, MG’s etc….. and if here in the game, I do so and incur EP penalties, well, that’s on me.

The Airstrike mechanics, well, I was taking casualties, I called for an AS on a village that had an enemy squad and MG within, I got denied twice…..further, with a Recon Huey ( with the air force base, signifying to me at least they were a FAC) I have seen several misses by F4 with bombs…..

Getting to my last point, it appears, that there is no recon or ‘spotter’ bonus. I have a co. leader, several squads and a FAC within 3 hexes and eyes on the target, with 6 visibility and miss a village twice? Surrounded by scrub? Hummmmmmm…. Don’t know if that’s codable but it would help……

[carll11]

I think these are excellent expectations...

US Forces:
Fire-for-effect on time in target hex: 80%
Scatter one hex: 5%
Scatter two or more hexes: 1%
Cancelled, rejected or not fired: 10%
Delayed one or more turns: 4%

Non-US Forces:
Fire-for-effect on time in target hex: 50%
Scatter one hex: 25%
Scatter two or more hexes: 10%
Cancelled, rejected or not fired: 10%
Delayed one or more turns: 5%