How Off-map Arty REALLY Works

[Treeburst155]

This is a little thing I put together for a PBEM buddy. I thought I'd post it here just in case some might find it helpful. If you think anything below is incorrect, please post.

How Off-map Artillery REALLY Functions

There are two types of off-map artillery, rockets and guns. Rockets do not fire spotting rounds, guns do fire them. I'll start with rocket artillery.

Rocket artillery is very inaccurate. Any friendlies within 500 meters are in danger, even if the spotter has LOS to the target. This is because the impact pattern is a large "target wide" pattern, and because the strike can be off-target even with spotter LOS established at the time of targetting and maintained throughout the bombardment. "Green line" adjustments to the target point may help bring the center of the impact pattern closer to the desired point, but there is no guarantee. The only way to be sure of an accurate rocket attack is to fire at a TRP, or to target the rockets during Turn 1 (prep bombardment). The large "target wide" impact pattern will still happen when targetting TRPs or doing prep bombardment; but the center of the impact zone will be on-target. Blind rocket attacks (other than TRP or prep bombardment) are VERY risky, and work the same way as blind gun strikes. Blind strikes are discussed below.

Off-map guns differ from rockets in several ways:

1) Spotting rounds are used.

2) The player can choose between two different impact patterns, "target" and "target wide".

3) The impact patterns cover a smaller area than rocket patterns, making fratricide less likely.

4) The player can be positive that a strike will be on-target before the first full salvo goes out.

Blind Targetting (Guns and Rockets)

Targetting a point out of LOS of the spotter almost guarantees an off-target strike. There will be no spotting rounds fired by guns when targetting blind. Subsequent adjustments to the target point may or may not bring the center of the impact zone closer to the desired point. I have occasionally managed to get an accurate strike with blind targetting; but it doesn't happen often. I'd guess the odds are no better than 1 in 6, probably much worse.

Impact Patterns for Guns

You have two choices here, "target wide" and "target". The first gives you a circular impact pattern. I like to make sure friendlies aren't within 120 meters of the target point when using "target wide". Most rounds will fall inside a circle of this radius; but even at 120 meters distance, friendlies are at risk.

With the "target" command you will get an elliptical impact zone, the deadly area being about 160 meters by 80 meters centered on the target point. The orientation of the long dimension of the ellipse can be north/south or east/west, depending on how the friendly map edge parameters are set. When the north map edge is friendly to one side, and the south edge friendly to the other, the long dimension of the impact pattern will be north/south. If one side has the west edge friendly, the other the east, the long dimension of the arty pattern will fall east/west. In cases of ambiguity, the program will cause the long dimension of the impact pattern to run east/west. This means that in most cases arty will fall parallel to the axis of advance, rather than along the front lines; but a tricky designer can easily make it so the impact pattern is the opposite of what is expected.

How To Hit Your Target Every Time

This section deals with guns ONLY. There is never any guarantee with rockets. I'm also assuming the spotter remains unmolested during the delay period, and while the strike is underway.

Accurate arty strikes require the following things to happen:

1) The spotter must have LOS to the target point when it is targetted (blue line).

2) The spotter must have LOS at the exact moment the first spotting round is FIRED.

That's it! The strike will be on-target EVERY time if you make sure these two things happen. However, #2 can be a bit of a problem. This is because spotting rounds are fired during the action phase of the turn, when you can't give orders. If smoke, or more likely dust, blocks spotter LOS, even briefly, at the exact moment the FIRST spotting round is due to fire, the spotting round will NOT fire, and the strike will be considered a blind strike by the program. There is nothing you can do until the next orders phase. Fortunately, the next orders phase is usually soon enough to prevent much wasted ammo and large scale fratricide due to the blind (inaccurate) strike. The key is to monitor your spotters closely during action phases to make sure spotting rounds do indeed fire. If they don't, you can bet there is an LOS obstruction. Cancel the strike during the next orders phase because, at that point, the strike IS blind and will likely be off-target.

Watching For Spotting Rounds

Don't do it! They are easy to miss on a busy battlefield, and where they land is irrelevant. Instead, select your spotter during the movie phase. This way you can watch for the beginning of the 60 second countdown and monitor the ammo counter. What you are watching for is the FIRING of spotting rounds.

Depending on arty caliber, spotting rounds will fire at the beginning of the 60 second countdown and/or the 30 second mark. As a general rule 105mm and up will fire two spotting rounds, one at 60 seconds and one at 30 seconds. Smaller guns and mortars will fire a single spotting round at 30 seconds on the timer. It is important to know the spotting round behaviour of the particular arty you are using. Run a quick test if necessary.

No arty fires more than two spotting rounds, and only the first one means anything. The second spotting round is pure eye candy stuff. In the case of 105mm, the first spotting round fires at 60 seconds on the countdown (right after the countdown begins). If you do not see the spotter's ammo count reduced by one at this point, spotter LOS is obstructed and the strike is blind. Cancel the strike promptly. With mortars you're watching for the ammo count to drop by one at the 30 second mark.

If the FIRST spotting round goes out, your strike will be accurate no matter where the round lands. You can even move the spotter out of LOS in the next orders phase. The strike will continue to be on-target. His job is done unless you want to adjust the strike.

It is very possible that the first spotting round will not fire; but the second one (at 30 seconds) will. This is because the LOS blockage, which prevented the first round from firing, cleared before the second spotting round was due to fire. The strike will still be off-target! Only the first spotting round matters. Be sure you know when this FIRST spotting round is supposed to fire for the arty you are using. It will either be at 60 seconds or at 30 seconds.

You need never again be surprised by a haywire arty strike that you thought was an observed strike.

EDIT: Green-line adjustments of ongoing ACCURATE strikes will always result in an accurate adjustment.

Treeburst155 out.

[ February 10, 2005, 10:53 PM: Message edited by: Treeburst155 ]

[Gpig]

Thanks for that, Treeburst. Very illuminating.

Gpig

[Kanonier Reichmann]

A brilliant summary Treeburst. Thanks a heap for simplifying and clarifying my understanding of how off map artillery works in CMAK & CMBB.

Regards

Jim R.

[Other Means]

Originally posted by Treeburst155:

{snip}

1) The spotter must have LOS to the target point when it is targetted (blue line).

2) The spotter must have LOS at the exact moment the first spotting round is FIRED.

{snip}

Treeburst155 out.

Thanks for the post but I belive this is not the case in CMAK. I think the spotter needs LOS *throughout the delay period*. If smoke or dust obscure the view throughout that period the strike is treated as being out of LOS.

I'd really like this to be tested, or if anyone has done it in the past could they post here.

I'll test it myself over the weekend if no one has any hard data.

[General Bolt]

TB,

Great post.

Here's another reference source CMWiki - Artillery page.

This wiki site is open to any contributers.

[ February 11, 2005, 06:32 AM: Message edited by: General Colt ]

[Treeburst155]

Other Means,

I've tested it. LOS is only important the instant the FIRST spotting round is due to go out, and during initial targetting. Give it a try. Verification is always nice. Just throw a couple direct fire smoke rounds in front of a spotter with a fairly long delay. Make sure the smoke is gone before the first spotting round is due. Timing this is not too difficult. Wind helps clear the smoke. The strike should be good. If it isn't, PLEASE send me the scenario file.

General Colt,

Thanks for the link!!

Kanonier Reichmann,

You're welcome!

Treeburst155 out.

[ February 11, 2005, 07:23 AM: Message edited by: Treeburst155 ]

[Dirtweasle]

I'll be damned, So this explains why adjusting an off target arty mission sometimes has no effect at all, when you'd think it should correct it. Thanks TreeBurst155!

[walpurgis nacht]

Mikey,

This knowledge will not save you.

I should be able to return a turn over my lunch break. :eek:

P.S., I have a few arty tricks to share myself in this thread. That is, just as soon as I finish using my @#$!#% and !@#%!@#%.

[Treeburst155]

Against you, Walpurgis, nothing will save me; but at least I won't bombard my own men with arty anymore.

Treeburst155 out.

[aka_tom_w]

This should have its OWN thread

CM Wiki Check it out!

I think this web page should be poste din TIPS and Tricks!!!

This is amazing

I have been Playing Combat Mission since the CMBO Beta Demo

and I had NO idea of this resource:

"Welcome to CMWiki

A Wiki is an interactive Web site that allows all users to participate in the knowledge-sharing process. CMWiki has been set up to provide tips, tutorials, and other goodies related to the Combat Mission games from Battlefront.

Please come in and join the fun. To edit, just register on either CMAKdb, CMBBdb, or here at the CMWiki. Press the Login button on any of these pages to get to the register link.

Everyone is free to write in the wiki. If you’ve never used the wiki language before, the playground is a perfect place to start."

-tom w

[ February 12, 2005, 04:08 AM: Message edited by: aka_tom_w ]

[Wicky]

Another tip appropriate to Russian arty spotters with long delays that I've used a couple of times is to give them orders ASAP ( but not prebombardment) for a blind strike then move them into a LOS position, which might take a few moves depending on the terrain. Once they're sitting comfortably and can see the spotting rounds viola job done.

[CombinedArms]

I remember TB155 writing up this research shortly after CMAK came out (the demo with all the PzIIIs vs Grants had lots of problems with dustclouds blocking arty observation, as I recall.) It's helped me ever since. But I never knew the wrinkle about the 60 and 30 second spotting round times.

Thanks for sharing.

(Other Means should know that TB did very extensive research on this at that time. I would trust his conclusions.)

BTW, the info about the "Target Wide" creating a circular rather than eliptical pattern is news to me--that could come in handy in certain tactical situations. TB, can you clarify a bit the diameter of the Target Wide circle? How does it compare to the length of the regular Target elipsis?

[Treeburst155]

Combined Arms,

The deadly diameter of "target wide" is about 240 meters, or 120 meters from the target point. This is of course a judgmental thing. I've launched "target wide" arty with friendlies just over 100 meters from ground zero. Sometimes I pay for this, other times not. The closer you fire to your own men, the luckier you have to be as far as outliers are concerned. Inside 100 meters is really asking for trouble with "Target Wide".

Treeburst155 out.

[ February 12, 2005, 07:49 PM: Message edited by: Treeburst155 ]

[Other Means]

Originally posted by Treeburst155:

Other Means,

I've tested it. LOS is only important the instant the FIRST spotting round is due to go out, and during initial targetting. Give it a try. Verification is always nice. Just throw a couple direct fire smoke rounds in front of a spotter with a fairly long delay. Make sure the smoke is gone before the first spotting round is due. Timing this is not too difficult. Wind helps clear the smoke. The strike should be good. If it isn't, PLEASE send me the scenario file.

General Colt,

Thanks for the link!!

Kanonier Reichmann,

You're welcome!

Treeburst155 out.

Brilliant. Thanks for this, I've been cancelling a lot of arty strikes. I play British mainly & the 2" mortar, while I love it dearly, has a terrible tendency to block my own spotters LOS - cue much curses from me. At least now I can check if I really need to.

Originally posted by Wicky:

Another tip appropriate to Russian arty spotters with long delays that I've used a couple of times is to give them orders ASAP ( but not prebombardment) for a blind strike then move them into a LOS position, which might take a few moves depending on the terrain. Once they're sitting comfortably and can see the spotting rounds viola job done.

This is also a brilliant tip. Cheers Wicky.

[GreenAsJade]

Thanks Treeburst for the excellent information.

Is it true, then, that a blind firing can be converted to a properly spotted one like Wicky says? That'd be great! I was thinking once it's blind it's always blind.

If they can be converted, then instead of cancelling, why don't we simply move the target point on a barrage that has LOS blocked at 60s to another green-line place. This will add some more small amount of delay, and give the chance

for the 60s spotting round to be re-fired and re-seen.... without starting again from scratch.

Will that work?

GaJ.

[Treeburst155]

I've been thinking about Wicky's tip. If it works, it means that LOS to the target point is ONLY required at the moment of the first spotting round. This could very well be true. My testing involved blue line targetting only. I really wasn't interested in targetting blind. I never do it.

With Wicky's tip, LOS is established at or before the time of the first spotting round. The strike never gets defined as blind. He targets blind; but the decision about the actual strike is not made until the first spotting round is fired. This is THE critical moment! Hence, Wicky's strike is defined as observed, and drops on-target.

Trying to green line adjust a strike that is ALREADY defined as blind due to blocked LOS at the critical moment probably would not work; but I can't be sure without specific testing. I'd bet against it working however. Once blind, always blind. The adjustment may work occasionally; but it wouldn't work all the time.

So, who's going to test this new thing out??

The answers we need:

1) Does Wicky's tip work? (It probably does)

2) If LOS to the target point of an ONGOING blind strike is established, can the strike be accurately adjusted EVERY time? IOW, can the strike be converted to "observed" status?

Treeburst155 out.

[Treeburst155]

Originally posted by GreenAsJade:

Thanks Treeburst for the excellent information.

Is it true, then, that a blind firing can be converted to a properly spotted one like Wicky says? That'd be great! I was thinking once it's blind it's always blind.

Wicky's strike is probably never defined by the program as "blind". He has LOS at the moment of the first spotting round.

If they can be converted, then instead of cancelling, why don't we simply move the target point on a barrage that has LOS blocked at 60s to another green-line place. This will add some more small amount of delay, and give the chance

for the 60s spotting round to be re-fired and re-seen.... without starting again from scratch.

I'd bet blind is blind....and green line adjustments don't trigger spotting rounds.

GaJ. [/QB]

Treeburst155 out.

[ February 12, 2005, 12:15 PM: Message edited by: Treeburst155 ]

[Treeburst155]

OK, I tested it. Once blind, always blind. Green line adjustments of ONGOING blind strikes will move the strike; but rarely to the newly targetted point. Adjusting blind strikes, whether green line or not, is a crapshoot. You never know where the rounds will fall.

This means Wicky's strikes are never defined as blind. So, we've learned a couple things:

1) With regard to ACCURACY, LOS need only be established at the critical moment (first spotting round). Isn't delay time affected by targetting blind???

2) Once blind, always blind....even if you establish LOS and adjust the ONGOING blind strike with a green line.

Treeburst155 out.

[ February 12, 2005, 01:24 PM: Message edited by: Treeburst155 ]

[Treeburst155]

Originally posted by GreenAsJade:

Thanks Treeburst for the excellent information.

If they can be converted, then instead of cancelling, why don't we simply move the target point on a barrage that has LOS blocked at 60s to another green-line place. This will add some more small amount of delay, and give the chance

for the 60s spotting round to be re-fired and re-seen.... without starting again from scratch.

Will that work?

GaJ.

Thinking further on this, if you notice the following bad situation during an orders phase, a green-line adjustment would salvage the strike:

1) First spotting round is likely to fire in the next minute.

2) LOS to target is likely to be blocked (lingering dust, smoke) during critical moment.

In this case, a green line adjustment would save the strike (barring new obstructions)....no need to cancel and start from scratch.

Treeburst155 out.

[John Kettler]

Concisely and brilliantly put!

These suggestions may also help. When firing in rain or similar visually degraded conditions onto damp ground, be advised that it is going to be extremely difficult to spot and adjust 81mm mortar fire or similar. Not only is the relatively small explosion proper (no more shock wave, remember?) going to be very blurred at range, but should it land in treetops, it will all but disappear, whereas in real life there would be great chunks of foliage blown skywards by the detonations. Even 105mm fire is hard to work with under such conditions. Rain's a bear, since, unlike fog, it can't be switched off. Thus, if it's overcast and raining, you're screwed. Plan on rewatching the movie a bunch of times as you search in vain for the spotting round. With low contrast ratios (haven't tried the explosion mods)

the task can be most challenging.

IMO, the LOS blockage check that determines the difference between a blind shoot and a controlled shoot is in the wrong place, unless we're modeling fire on a rapidly moving target. Seems to me that the FO ought to be able to call in the grid, with or without LOS, but that the real decision point should be when the spotting round arrives. That's how he adjusts fire. Can he see both the target and where the spotting round landed relative to it? If not, I believe the normal procedure is to call "lost" or similar and call for another spotting round, NOT fire for effect blind.

Regards,

John Kettler

[CombinedArms]

John K,

I think all would agree that the way it works is problematic--certainly not the ideal situation by any means from the standpoint of realism.

I'm not sure, however, that the player has to look frantically for the spotting round. As TB says, the only important question from a play standpoint is whether the round is fired at all. If you have 81mm that starts firing with no spotting round being deducted, before firing for effect starts, from the numerical count--then cancel the mission and start again with a blue line. For 105, it should shoot two rounds (but the first one is what matters.) Green line retargetting won't work if the round doesn't shoot.

If the spotting round is fired at the right moment, on the other hand, even if off target, the fire mission will be on target. As TB says, the critical moment is the precise second when the first spotting round should fire. If LOS is clear to the target at that second, the mission will be on target. Otherwise, it not only will be off target, but it can't be salvaged without cancelation. This is problematic indeed, but what we have to live with till CM2x.

[CombinedArms]

I decided to test Wicky's suggestion and it works! To keep it simple, I used a US 81mm FO, placed him on one side of a bank of large buildings, and had him spot to a point on the far side of the buildings, out of LOS. The spotting time was four minutes with a black line to the target.

Then he simply walked through the building on turn two, at some point acquiring LOS to the target. The spotting time wasn't shorted at all due to the fact that he had direct LOS, but on the other hand, the spotting round ticked off his ammo count at precisely 30 seconds from firing time and the mission was right on target.

Later, he targeted in the other direction, toward what was now the far side of the buidling, again with no LOS, then walked back through the building, acquiring LOS as he went. Again, the spotting round took off at 30 seconds and the mission was on target.

So, I'm convinced that Wicky is right and that TB's thesis is also correct--in terms of the accuracy of the fire mission, the only thing that counts is having direct LOS at the moment the spotting round is fired.

[Treeburst155]

I believe US 105mm spotters have their first spotting round fire at 30 seconds (the exception to the rule), the German 105mm at 60 seconds. Players really should test the particular arty spotter they are using. You can even do it in-game much of the time. There may be many exceptions to the rule. I never did test all the spotters in the game for when their particular critical moment happens. Heck, there may be a critical moment for some spotter that is at 45 seconds. I doubt it; but I never actually determined the critical moment for all spotters, and can't remember for others.

Treeburst155 out.

[Wicky]

Cheers for testing it out - I discovered it in a PBEM when I had a 75ish non-radio soviet spotter as a reinforcement at the back of a map with something like a 8 minute firing delay. I couldn't transport him to where he was needed, so with nothing to lose I set the blind firing line and got him trudging across the map for 5-6 turns, sneaked him into some scattered trees on the crest of a rise overlooking the bottleneck I'd foreseen and with LOS everything proceeded as normal, I even switched to green retargetting and swapping for smoke as appropriate.

Looking back, does it qualify as a gamey bug or sumfink

[GreenAsJade]

So back to my question then.

Suppose you see that at 60 there's no spotting round because LOS is blocked. Normally what you would do is cancell the firing orders. Now it seems that you should be able to give adjustment orders. There should be a 60s delay added to the round, so you have time to get back into LOS again and everything will be fine. Right?