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Reverse slope/grazing fire.

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It's very annoying not being able to fire in a direction because you can't see an action spot on the floor. I realise why: having a 2D interface for a 3D world.

What would be brilliant is, if you ever get "reverse slope no aim point", you instead got "grazing fire" to the point, and your unit could fire at it with the expectation they'd be shooting over the area, that would do it?

So you can setup MG fire to keep a units head down even if you can't fire at them.

The engine would need to model the vertical separation between the fire and the unit, of course, to work out suppression but it would remove one of the last remaining gripes.

...am I in the first hundred to suggest this?

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Grazing fire has been asked for before. Grazing fire as the default for when the game says "reverse slope target - no LOS", I think that might be a first! :)

I could really do with some o' that right now... there are ATGs that I can't area fire at until the unit firing has spotted them. But if the tanks can't get some HE into the ATGs before they spot them, the ATGs will do 'em in...

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Grazing fire has been asked for before. Grazing fire as the default for when the game says "reverse slope target - no LOS", I think that might be a first! :)

I could really do with some o' that right now... there are ATGs that I can't area fire at until the unit firing has spotted them. But if the tanks can't get some HE into the ATGs before they spot them, the ATGs will do 'em in...

I believe Womble's thread : http://www.battlefront.com/community/showthread.php?t=112956 asked this quite recently.

But it never hurts to ask again :D

And good suggestion.

So saying, in effect, fire over this AS, we've voted 100% that it works so far ;)

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*super necro powers*

As it has been mentioned elsewhere, grazing fire (and theoretically also indirect fire) is possible right now in certain situations. You can let your units fire in a "flat" manner over ground if you position your units properly and the terrain is suitable. So it's not really a feature, but rather a very complex work around.

From my observations, it depends on the height of the firing weapon in relation to the height of the aimpoint on the area-targeted tile. Draw a line between those two and you get the path/angle of the projectile. If the line continues close to the ground for a long distance "after/behind" the tile you've aimed at, what you achieve is grazing fire. They bullet stays dangerous as it travels on.

Since the aimpoint is hardly ever on the exact same height as your muzzle, the distance between the muzzle and the area-targeted tile plays a major role. The higher your muzzle, the greater the distance to the targeted tile needs to be in order to achieve a "flat" trajectory. Therefore, it's pretty much impossible to get a flat trajectory with the main gun of a tank atmedium ranges. A prone infantryman with a MG, however, can get a flat trajectory at medium ranges. At extremely short ranges though, even the prone MG will get a "negative"/downwards pointing angle, firing into the ground at the area-targeted tile - so I assume the aimpoint must be slightly lower than the muzzle-height of a prone infantryman.  

To sum it up, you need to consider the height of your muzzle, the height of the tile you're targeting, the distance to it, and - importantly - the shape of the ground "behind" the area-targeted tile. You want your bullets to travel close to the ground after it passes the targeted tile. 

--------------------

Of course you still require a LOS on the tile you want to target. So, while small muzzle heights are generally good for grazing fire, they also suffer from terrain that obscures LOS (from my observations, each terrain type has a LOS-reducing value and a "height"). If you're on a hill or in the upper floor of a house, you have an easier time spotting enemies (as your LOS travels above most terrain tiles and thus cuts through fewer terrain tiles), but you trajectory is not flat.

It's also worth mentioning that the distance to the aimpoint affects your rate of fire. Before firing a shot or burst, a unit needs to aim, and the time it takes to aim depends on the distance to the aim-point (for a regular XP unit, I suppose it's ca. 1 second aiming per 100m distance). As you're generally targeting tiles that are much closer to you than your actual target zone, using the grazing fire method described here will result in relatively high rates of fire (and ammo consumption).

I also need to point out that due to its high ammo consumption, this method of grazing fire is not really usefull except for very few situations - mainly for MG flanking fire along the path of the attacker. With "target briefly", it can also be handy to make some impression on distant targets that pop out only for very short durations - if you don't use area-target, your units' aiming takes too long so they don't fire at all. Last but not least, it could probably be used for heavy MGs, whose capability for indirect fire is underrepresented in the game (also due to maps being too small in many cases). It would be interesting to place a heavy MG on the reverse slope of a very gentle hill. The MG would have many tiles in front of it, with the height increasing very gently from one tile to the next. This would allow you to fine-tune the elevation of the gun (by area-targeting different tiles). And then you'd need to observe where the bullets "land" (affected by bullet drop) for each elevation. Interesting idea, but probably not very practical :D.

The only thing you'd really need to make intentional grazing and indirect fire a real thing in Combat Mission is some form integrated gun-elevation. E.g. you should be allowed to target reverse slopes if the circumstances (1) terrain, 2) max/min elevation of the gun, 3) bullet or projectile drop, distance to the target) would allow an effective line of fire on that tile (one that is close enough to the ground to inflict suppression).  It would make a lot of sense for MGs and also infantry guns which, by the way, are also also underrepresented in the game right now (they suck because you can't make them fire indirectly!). Right now, you need to elevate the gun by firing at a tile that has a suitable height (if you're lucky enough to have one within your LOS...). 

Edited by Kaunitz

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If both tiles have the same height, it could work, especially since there is always some random dispersion? From my understanding, given a perfectly flat terrain, your bullets will cross through the "effect zone" at a greater height if you aim "behind" the zone. As soldiers tend to go prone (reduce their height), such a fire might be less effective .

If you aim short of the effect zone, by contrast, your bullets will cross the effect zone at a lower height, if at all (if they don't hit the ground in the effect zone that is), which is more dangerous for prone soldiers.

But really this depends on the exact height of the "aim point" which is unknown?

 

Edited by Kaunitz

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1 hour ago, Kaunitz said:

The only thing you'd really need to make intentional grazing and indirect fire a real thing in Combat Mission is some form integrated gun-elevation. E.g. you should be allowed to target reverse slopes if the circumstances (1) terrain, 2) max/min elevation of the gun, 3) bullet or projectile drop, distance to the target) would allow an effective line of fire on that tile (one that is close enough to the ground to inflict suppression). 

Interesting idea.  But, as you say earlier - only useful on larger maps.  Presumably you would need LOS of 2 Km or more.

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In my eyes, "large" CM maps are just medium maps, really. Small maps usually lack ("cut off") observation and support positions. This in turn means that many units suffer disproportionally, especially scouts/observers and other recon elements as well as support elements (assault guns, infantry guns). Due to the tiny size of many maps, these units are forced into closer, uncomfortable ranges to the "frontline". Ranges at which they're spotted more easily and at which the opponent's shots miss rarely. Also, since the overall number of positions is limited on a small map, artillery can be extremely dangerous - there are only so many positions where the enemy can hide, which again increases the weakness of the aforementioned units which are typically only lightly armored. 

Anyway, back on topic! :D

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+1  Couldn't have said it better.   This is main reason CM1 is still played as it is very easy to play on a 8Km x 4Km map with more than a reinforced Regiment Task Force on each side.

One of the mission types I miss in CM2 is the "vehicular recon".   Distances are rarely large enuff to justify em.   Usually it's better to dismount any recon vehicles and recon crews on foot.  And recon vehicles and inf units nearly always get used as conventional troops.

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Well, I suppose the problem with larger maps (apart from the technical/performance issues it might bring) is that the scales would get mixed up. In some instances, I wished the game had turns of 30 rather than 60 seconds and smaller/more action squares. If we'd have larger maps, however, most of the 60 second-turns would still be utterly boring. So gameplay would really suffer from the mix of scales. A very fine resolution of time and space fits to the tactical, but not to a grand-tactical/operational scale. Also, to a certain extent, positions that are farther away are already represented by offmap support, even though it's nice to see these units as 3D models on the battlefield. :) 

So it's really hard to draw a line here. I prefer relatively large maps with relatively few troops. The larger maps are just enough to allow for properly spaced-out support positions. Give me more troops and I'm overwhelmed by the load of micromanagement. Give me smaller maps and it feels "bottlenecked" and a bit unrealistic. I also have to admit that I think that CM is set on a very small tactical scale, which primarily is about playing it "right". 

Of course landscapes differ a lot in the real world. So I'm not denying that in some situations, maps can be small without any loss of tactical complexity. But overall, my gut feeling tells me that the engagements are a bit too crowded and close in Combat Mission. It's interesting to compare CM engagements with those that another game I like to play, Command Ops II, creates (in terms of distance, troops involved, duration of engagement, losses caused by engagement). Command Ops is set on the grand-tactical/operational level and also features maps that are true to scale. On this scale, scouting makes perfect sense. (And also, you'd rarely attack with infantry in daytime in Command Ops, which is standard for CM  - well, it's because of all the graphical eye candy again, I guess ;) ).  

I think that the problem, if you want to call it such, becomes more noticable with the "modern" titles (Black Sea). The more the operational and tactical spheres are intertwined in reality, the more problems you run into with a game engine that is designed to represent only the tactical sphere.

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3 hours ago, Kaunitz said:

From my understanding, given a perfectly flat terrain, your bullets will cross through the "effect zone" at a greater height if you aim "behind" the zone. As soldiers tend to go prone (reduce their height), such a fire might be less effective .

It might cause fewer casualties, but since more bullets would be whizzing through the enemy-occupied AS, it might do a better job of keeping their heads down. Furthermore, if the enemy got tired of laying there and decided to run off, the act of standing up would put them back into the line of fire. Since I haven't tested this, I don't know how it actually plays out in the game. I'm just hypothesizing.

Michael

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Here is a diagram I've quickly tossed together, showing the effect of distance and muzzle height in relation to the aimpoint. If your aimpoint is at a different height than your muzzle, increasing the distance to the aimpoint results in a flatter trajectory, which can be used for grazing fire. Note that for the two muzzle points at lower height (red + blue), the intended grazing zone would be reverse-slope and could not be targeted. 

(Of course there is always some random inaccuracy/deviation from the "ideal" lines. This is not shown in this pic.)

1111.png

Edited by Kaunitz

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I remember reading a memoir of a British soldier in WW1. He noted the difference of sound, and therefore trajectory, of both MG and rifle fire on trenches. Germans would allow their bullets to drop "with a smack" into an obscured trench, when they did not have a good firing solution. The soldier considered to be much less dangerous than fire coming from flatter trajectories, as those did have a firing solution (snipers, he thought) and kept the infantry pinned.

Either way, using direct fire weapons for indirect effect seems to be a common tactic, especially in desperate circumstances.

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By the way, does anyone know why onmap self-propelled arty/short-barreled* assault guns/howitzers can't fire indirectly in Combat Mission's WWII titles? Is it because the trajectory wouldn't be curved enough to hit anything on the smallish maps? Note that you do get the option to fire indirectly with onmap infantry guns, and the game takes into account the trajectory somehow (you can get the "No line of fire" error-message if the gun can't fire over an obstacle in the way).

By the way, I guess that the slightly arced trajectory of assault artillery can be important when using area fire. Simply because the shells will land closer to the intended target, considering the base inaccuracy, because the shells travels at a higher/safer altitude? By contrast, if you fire a flat trajectory gun over flat terrain, the base inaccuracy can make the shell hit the ground anywhere in between the gun and the target (or behind the target), potentially threatening your own troops on the way.I need to conduct some tests to see whether this is true. If it is, it's just another way in which Combat Mission is awesome ^^. Firing over the heads of the attacking infantry was one of the prerequisites of assault guns... Also, these guns should be more effective against trenches (depending on terrain, flat trajectories can miss by a lot if slightly off target...with a curved trajectory, a shell should be closer to the target). But this would probably only matter if trenches offered more protection in the game (right now, lacking proper slit trenches and hastily dug fighting positions, trenches are eliminated much too easily by arty/mortars)

*Sturmgeschütze (lit. assault guns) started out as proper assault guns, but ended up as long barreled tank destroyers - their role was taken over by "Sturmhaubitzen" (lit. assault howitzers), if I get the story right.

Edited by Kaunitz

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2 hours ago, Kaunitz said:

By the way, does anyone know why onmap self-propelled arty/short-barreled* assault guns/howitzers can't fire indirectly in Combat Mission's WWII titles?

Just because if they are on map their intent was to be used in direct support. If those systems were used as artillery they will be available for purchase in the off map artillery panel. The infantry guns have a setup / packup time that is non trivial. Even if that does not accurately represent how long it would take to setup for indirect called fire it is a deterrent for moving them around. Tracked assault guns have no such setup and therefore it would be odd to allow them to pull up to a spot and become available on the indirect call list.

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IIRC This German infantry support gun in game can both fire directly and indirectly - I think it features in a scenario with probing Greyhounds in drizzle on a longmap with flanking options.

 

Edited by Wicky

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44 minutes ago, Wicky said:

IIRC This German infantry support gun in game can both fire directly and indirectly - I think it features in a scenario with probing Greyhounds in drizzle on a longmap with flanking options.

Yes, onmap crew-served infantry guns can fire indirectly in Combat Mission games. 

The big problem with infantry guns and assault guns is that - like all other troops - they can't target an action spot unless they can draw a LOS to the ground of the tile. If your unit is at the same height as the target-tile, you can't fire at it. So for example, if you'd like your infantry-gun to fire "50 meters in front of that barn", they can't because grass might block their LOS on the ground of that particular action spot. While this affects all troops, it particularly weakens support weapons, whose purpose should be to knock out targets quite accurately with their strong HE ammo. It's a shame really, because I have a soft spot for those non-tank vehicles. But right now, they seem to be quite useless. :( You can still attempt to shoot at some spot in front of the desired target-spot and hope that some shell might at some point land somewhere close to the target due to random inaccuracy, but nedless to say this wastes ammo (those support weapons don't have that much to begin with...) and gives away their position.

2 hours ago, IanL said:

Just because if they are on map their intent was to be used in direct support. If those systems were used as artillery they will be available for purchase in the off map artillery panel. The infantry guns have a setup / packup time that is non trivial. Even if that does not accurately represent how long it would take to setup for indirect called fire it is a deterrent for moving them around. Tracked assault guns have no such setup and therefore it would be odd to allow them to pull up to a spot and become available on the indirect call list.

Yes you're right. Also, I figured out that the kind of indirect fire I had in mind (shooting over larger obstacles) is rather impossible for the self propelled howitzers on CM maps. Even when elevated as far as possible, they would probably "overshoot" the standard CM-map sizes. The infantry gun, on the other hand, has really astonishing gun elevation (see video linked by Wicky).

Edited by Kaunitz

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The ability to area target what can't be seen would be open to abuse ingame* due to player overview (read up on problems with borg spotting in CM1) - plus without oppo AI side having the same capability would give human player a massive advantage.

* on map mortars at the 50mm ones are permitted to target 5m or so beyond LOS limits so giving them the ability to put rounds behind walls, over the top of hill etc

Grazing fire can partly be mimiicked esp with MGs area firing as far as LOS permits and rounds will splash further beyond making suppressive effect.

Edited by Wicky

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38 minutes ago, Wicky said:

Ability to area target what can't be seen would be open to abuse ingame due to player overview - plus without oppo AI side having the same capability would give human player a massive advantage.

The problem is that the game would need to differentiate between an "area that can't be seen because it's behind a hill or a house" and an "area that can't be seen because it's behind 10 tiles of 50cm high grass or a single bush". In other words, the targeting point used for determining LOS needs to be set at a higher altitude. If you get a reverse slope (can see a point up to ca. a man's height "above" the targeted tile), you should be allowed to area-fire. There are probably good reasons why it's not that simple, but it really affects gameplay in a bad way. It's ridiculous that an MG or a an infantry gun cannot fire behind/through a bush. If your infantry came and told you "There is an enemy MG nest giving us a hard time, 50m short of the barn" with a hand singal in the direction and you ordered your gunner: "50m short of the barn, straight ahead!" you wouldn't expect him to answer "Sir, I can see the barn, but I can't see that particular spot 50m in front of it. It's obscured by a bush!" 

Already the AI doesn't know how to area-fire. But who cares! This game is meant to be played against human opponents anyway! :D

Edited by Kaunitz

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Shufty left or right a tad, or shoot at bush, splashing beyond, to shoot past bush.

IIRC enemy AI can shoot area fire at last seen/spotted icons as seen from their viewpoint for a certain time.

Edited by Wicky

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9 hours ago, Wicky said:

Shufty left or right a tad, or shoot at bush, splashing beyond, to shoot past bush.

 

I want to see how you shift an infantry gun right or left a bit quickly. Also, movement draws attention and moving sideways makes you a bigger target.

Shooting at the bush, hoping for the shell to travel farther because of inaccuracy is a solution, but a very, very bad one. It wastes ammo (large calibre support guns have little ammo!), warns the enemy (if it's in between two rounds, he may retreat/react in time), gives away your position and you might run the risk of hitting your own troops, depending on the terrain. It also depends on how far "behind" the bush you want to fire. If its but a few spots, it may work, if it's more, then it's still impossible.

Edited by Kaunitz

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By the way, here is a quote from an official post on spotting (I completely messed up the formating, so there is no quotebox, sorry - quote is in bold format):

2. Why can't you Area Target a particular point of an Action Spot at various heights, not just the default 1m height (which IIRC is the default)?

It is a similar answer to the above. You can target a unit, with it's specific height considered, in a way that makes sense because it is a point to point LOF calculation. But to Area Target a specific point of an Action Spot isn't straight forward. Sometimes you want it to be the ground, other times you want it to be 1m in the air, other times you might want it to be even higher. How is CM supposed to understand what it is you want to do? It can't. And having some sort of clunky UI to manually change the aim height is something we won't do.

BTW, it is wrong to say there is no grazing fire. Dead wrong. It's in the game and it works perfectly well. What you can't do, at least easily, is ensure that a specific spot of ground is covered by a specific height of fire.

So the "aimpoint" for determining LOS seems to be set at a height of ca. 1m. In this topic, I've argued that this is too low and should be increased to ca. 2m (reverse slope height). This would help support weapons to fire at spots at which they should clearly be allowed to fire, while still keeping them from firing at places they can't see (you still can't fire over a hill or house or a wood...).

It might also lead to more interesting and realistic (imho) infantry fights in H2H battles, with both sides using area fire at supposed enemy positions and more suppression going on (--> longer duration of engagements, casualties are inflicted slowlier). Right now, if both sides are prone, it often happens that you can't bring any fire in the direction of the enemy at all because the the line drawn from your prone spotter-eyes to the aimpoint lies below the height of the terrain tiles (which block LOS). [see my explanation here: http://community.battlefront.com/topic/125278-highlanders-the-battle-of-gerbini/?page=3&tab=comments#comment-1748174] Therefore, the first unit that gets up and shows their heads above the height of the terrain, gets hit by direct fire. It would be cool if more area fire was going on. From my understanding and also scanning through period field manuals, this is not too far off the mark of how infantry worked. A few people in the squad would try to spot and call out the targets to the other members of the squad/the squad leader, who would then announce the target to the whole squad or just a fire group and determine the number of rounds to be fire, etc. It's also the reason why "obvious" (easy to call out) positions was to be avoided. But back on topic!  

It's certainly true that grazing fire can work, but the circumstances have to be very, very specific. It can't be used as flexibly and intentionally as it should, imho.

However, this quote probably also shows the problem with increasing aimpoint height: If you increase it, all area fire from a weapon with a muzzle-height below that height will be directed "upwards" and hardly have any effect on the targeted area (especially if the enemy is prone). Solution (not knowing any details or intricacies of the game's inner workings...): LOS-aimpoint and area-FIRE-aimpoint should be seperated. The LOS aimpoint should be set higher than it is now (ca. 2m), allowing players to fire at reverse slopes. The area-FIRE-aimpoint should stay the same (ca. 1m), so that units don't fire into the air above the targeted spot, but at/close to the ground. Of course, if the reverse slope is caused by some hard cover (stone wall, ridge), this means that your fire will hit that hard cover (especially if you have a weapon with a flat trajectory). If, however, the reverse slope is caused by some lousy soft cover (like terrain tiles, foliage, bushes), then you can still fire effectively through/over the cover. In both cases, you'd still need to have a LOS on the area (2m above the area)

 

PS: 

 

 

Edited by Kaunitz

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Some additional info: In the link posted as post scriptum in my previous post, MOS:96B2P quoted official sources that there are 5 heights in the game: prone, kneeling, standing = small vehicle, tall vehicle, very tall vehicle. According to Vanir Ausf B's addition, reverse slope height extends to "very tall vehicle" height (so it's taller than a man). LOS aimpoint height is 1m above the ground.

I've also rediscovered my own video, showing some MG grazing fire action: 

The MG can only area-target a spot at 180m distance. Tiles at greater distances are in reverse slope areas (LOS gets blocked by cumulative tall grass tiles that at some point act like a wall that casts a LOS-shadow/dead zone) and therefore can't be area-targeted. However, as the angle between the muzzle (prone height) and the area-targeted tile's aimpoint (height = 1m) is suitable and the terrain beyond the area-targeted tile is flat, the MG's bullets travel on much further at a dangerous, effective (suppress/kill) height.

Edited by Kaunitz

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