Urban combat primer - in progress -

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Klingon
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Urban combat primer - in progress -

Post by Klingon » Mon Mar 25, 2013 4:04 pm

Buildings have a rating (light, medium, heavy, and hardened) and a Construction Factor (CF). They are immobile targets, and are at a -4 to hit them... but you have to have LOS to the bottom level of the building to shoot it.

Rating is the general structure of the building, CF is how robust it is, and how much weight it can support.

Light: generally open structure, not damage resistant. Residential houses, small businesses, that sort of thing.
Medium: larger businesses, more solid construction, like museums.
Heavy: Factories, concrete or steel docks.
Hardened: military bunkers, bank vaults.

If your tonnage exceeds that of the building you are on (or in, and not on the bottom floor), it will collapse under you, and you will fall into the rubble. This will usually be a bad thing, but there might be circumstances when you want this to happen (like if your opponent has holed up lots of infantry in it). If you are on the bottom floor and your tonnage exceeds the CF, any basement in the building will collapse under you, so it is a very valid tactic to do enough damage to get a building's CF under it's occupant's, if he's using it to absorb damage. Get lucky with that basement, and that tactic will backfire on him:
  • 2 Double basement. The unit falls 2 levels. Apply all damage to a ’Mech’s legs (use the Front column of the ’Mech Kick Location Table).
    3 Basement. The unit falls 1 level. Apply all damage to a ’Mech’s legs (use the Front column of the ’Mech Kick Location Table).
    4 Basement. The unit falls 1 level (for ’Mechs, use the Front/Rear column of the ’Mech Hit Location Table).
    5-8 No basement.
    9 Small basement. Infantry may move into the basement as though it were a new level of the building (Sublevel 1); ProtoMechs cannot enter this level. No effect on ’Mechs or vehicles. Not coded in megamek.
    10 Basement. The unit falls 1 level (for ’Mechs use the Front/Rear column of the ’Mech Hit Location Table).
    11 Basement. The unit falls 1 level. ’Mechs fall headfirst (use the Front/Rear column of the ’Mech Punch Location Table).
    12 Double basement. The unit falls 2 levels. ’Mechs fall headfi rst (use the Front/Rear column of the ’Mech Punch Location Table)
When a building collapses, it will inflict damage to units inside it as follows:
(CF/10)*#levels (CF is the construction factor at the beginning of the phase, rounded up when you divide by ten), AND any unit in the building's basement will automatically be destroyed (it's buried in the rubble).

So, a 6 level building that started out as CF 90, been reduced to 25 at the beginning of the phase, will inflict 18 points of damage when it collapses. (2.5 rounded up to 3, times 6 is 18)

Entering the building: when you enter a building, you will pay additional MPs based upon the rating of the building, and you will roll a PSR to avoid damage. The PSR modifier will depend on the building rating; if you fail, you do not fall, but you do take damage equal to the CF/10 rounded up. Once in the building, though... watch for basements (see above). Also note that you will also inflict your tonnage/10 to the building's CF when you enter it.

If you are in a building and you are shot at, if you are not infantry, the building will absorb its CF/10 rounded up, where the CF is the CF at the beginning of the phase. So, with the above building, say you're in it, and there's a Locust on top of it. CF is 25, so no problem, but you get shot by a PPC, 4 medium lasers, and 12 points of LRMs. Every attack gets 3 points peeled from it and into the building instead, you you take 7 points from the PPC, 2 points from each of the mediums, the 5/5/2 groups from the LRMs get the same treatment so the first two groups do 2 points, and everything else goes into the building. 3 points from the PPC, each of the 4 mediums, and the LRM groups, so the building just took 22 points. Now the CF is only 3, and that Locust is easily enough to collapse it on top of you, then try to fall on you.

Last note: a building level is one level high, and while a mech is nominally 2 levels tall, when it's in a building, it's only one. So you can hide by entering a L1 building behind another L1, and you can punch ground vehicles, infantry, other mech's legs... options abound.

Infantry:

Infantry units do not pay a cost to enter the building; just the 1 MP to enter the hex (2 for mechanized infantry).
When infantry are in a building that is fired on, damage is passed through according to the rating: no damage for hardened, 25% for heavy, 50% for medium, 75% for light. This can result in infantry taking more damage than if they were not in a building.
Infantry take triple(!) damage from collapsing buildings.
Last edited by Klingon on Fri Apr 26, 2013 12:12 am, edited 3 times in total.
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Re: Urban combat primer - in progress -

Post by Crucis lancers » Fri Apr 19, 2013 4:41 am

question:
1: can you push units agaisnt buildings? if so what kind of effect it makes.
2: is there a way to kick push displace other mechs from the top of a building? .
3: can you DFA a mech wich is in the top of a buildin and whata re the effects if you fail or land the dfa.

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Re: Urban combat primer - in progress -

Post by Klingon » Fri Apr 19, 2013 5:43 am

Crucis lancers wrote:question:
1: can you push units against buildings? if so what kind of effect it makes.
Yes; the mech pushed against the building makes a 1 hex charge against the building. In essence, it'll take CF/10 to the side facing the building.
Crucis lancers wrote:2: is there a way to kick push displace other mechs from the top of a building? .
To a mech on top of it, the building acts just like a hill of the same height, except that the hill might get shot out from under you. Pushes, charges, and DFAs all will displace a mech; if that hex it goes to isn't on the building... down she goes.
Crucis lancers wrote:3: can you DFA a mech which is in the top of a building and what are the effects if you fail or land the dfa.
Normal effects of a DFA. A target being on a building has no effect on the DFA, except that it can make the aftermath interesting... and/or painful.
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serrate
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Re: Urban combat primer - in progress -

Post by serrate » Wed Apr 24, 2013 4:39 pm

Entering the building: when you enter a building, you will pay additional MPs based upon the rating of the building, and you will roll a PSR to avoid damage. The PSR modifier will depend on the building rating; if you fail, you do not fall, but you do take damage equal to the CF/10 rounded up. Once in the building, though... watch for basements. The chart rolls for the basement, with 5-8 giving no basement, and 2 and 12 being a 2 level basement; one has you falling on your head, falling damage goes to punch table. It's very rare, but it can happen.
I just want to say, that in general within MMN, entering a building with a mek is a terrible idea. The randomness of basement rolls is the real killer. I was in a nasty city fight once, and was down to 2v2, but his 2 were crippled and one of mine was pristine. Instead of being patient and getting the sure win, I decided to push through a building with that pristine mek, and the next thing you know auto-win kicked in. Apparently, there was a basement, and I entered that basement on my head. A terrible decision cost me a mek that I liked and a win that was almost definite.

From a discussion in Main the other day, this is by no means an isolated incident. I'm not sure of the exact rolls and numbers required for something truly bad to happen when you enter a building, but I think the chances are great enough that I simply won't attempt it, ever. It's just not worth it.

If you have more success with it, or if you have more info about the specific rolls and target numbers required to be successful in this move, please post them. I'd be very interested to hear more about it. Who knows, maybe my experience really was a fluke; but if I understand the basement rolls correctly, it's not.

Thanks for the guide Klingon!

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Re: Urban combat primer - in progress -

Post by Jackal » Wed Apr 24, 2013 6:03 pm

serrate wrote:I just want to say, that in general within MMN, entering a building with a mek is a terrible idea. The randomness of basement rolls is the real killer.
I'd like to amend that just by saying that entering a building with a mek is a terrible idea *unless* you have no better option available to you. For example, I've sometimes had jumping mechs fall in very bad places in city battles (ex: missed a kick and fell, now can't jump out, and is surrounded by enemies). Many times in the past, I've been a able to keep these units alive by making a last-minute, surprise move into a building where damage from weapons is reduced and the mech is immune to physicals (unless they're able to destroy the building first).

Basements can be thought of as adding a risk element to something that would otherwise be an overwhelming advantage to a mech (for a long time on MMNet we had buildings without basements that were purely advantageous places to move).

All that said, it's definitely something to only do in an emergency. Don't move into (or through) a building just to save time.

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Re: Urban combat primer - in progress -

Post by Klingon » Thu Apr 25, 2013 12:07 am

  • 2 Double basement. The unit falls 2 levels. Apply all damage to a ’Mech’s legs (use the Front column of the ’Mech Kick Location Table).
    3 Basement. The unit falls 1 level. Apply all damage to a ’Mech’s legs (use the Front column of the ’Mech Kick Location Table).
    4 Basement. The unit falls 1 level (for ’Mechs, use the Front/Rear column of the ’Mech Hit Location Table).
    5-8 No basement.
    9 Small basement. Infantry may move into the basement as though it were a new level of the building (Sublevel 1); ProtoMechs cannot enter this level. No effect on ’Mechs or vehicles.
    10 Basement. The unit falls 1 level (for ’Mechs use the Front/Rear column of the ’Mech Hit Location Table).
    11 Basement. The unit falls 1 level. ’Mechs fall headfirst (use the Front/Rear column of the ’Mech Punch Location Table).
    12 Double basement. The unit falls 2 levels. ’Mechs fall headfi rst (use the Front/Rear column of the ’Mech Punch Location Table)
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Re: Urban combat primer - in progress -

Post by Jackal » Thu Apr 25, 2013 3:54 am

Actually if 5-8 is no basement and 9 is effectively no basement, the chance of no basement is 66%.

5 = 4/36
6 = 5/36
7 = 6/36
8 = 5/36
9 = 4/46

4/36 + 5/36 + 6/36 + 5/36 + 4/46 = 24/35 = 66%


Also, even if there is a basement, you will not fall into a basement as long as the CF is higher than your mech's tonnage. That said, if the CF is reduced below your tonnage by weapon fire/physicals then it will collapse at that point.

serrate
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Re: Urban combat primer - in progress -

Post by serrate » Thu Apr 25, 2013 8:29 pm

Thanks for all the extra info. I guess it's not as much assured destruction as it seemed, and I just got very unlucky. I wish the client displayed that phase, it would take a lot of the mystery out of it.

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Re: Urban combat primer - in progress -

Post by Bloodknight » Thu Apr 25, 2013 9:11 pm

I guess it's not as much assured destruction as it seemed
The chance is 1/3 that the building has a basement and the building needs to be below the CF of the entering unit's weight for the basement to cave in. One important point that is yet missing from the urban combat primer (which, I hope, goes into the wiki) is that units in a basement are automatically killed if the building above them gets reduced to 0 CF, they become buried in the rubble.

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Re: Urban combat primer - in progress -

Post by Klingon » Fri Apr 26, 2013 12:10 am

Bloodknight wrote:
I guess it's not as much assured destruction as it seemed
The chance is 1/3 that the building has a basement and the building needs to be below the CF of the entering unit's weight for the basement to cave in. One important point that is yet missing from the urban combat primer (which, I hope, goes into the wiki) is that units in a basement are automatically killed if the building above them gets reduced to 0 CF, they become buried in the rubble.
I'd forgotten that detail, thanks! Yeah, trying to get it all ironed out before putting it in the wiki. This stuff is too universally applicable to keep to house only, I think.
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Re: Urban combat primer - in progress -

Post by Nastyogre » Sun Jun 23, 2013 7:33 pm

I realized this a couple games back. You need to be careful with low CF buildings. Some mechanized infantry can run over twenty tons, so you could collapse the building on yourself. Lower weight infantry are the best for the exploration technique.

This is especially useful for vee forces, because 4 infantry are always use able. More than 1 is not possible for mek conquers.

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Re: Urban combat primer - in progress -

Post by Deadweight » Tue Dec 10, 2013 10:45 am

Perhaps you could post a list of good urban units.

Obviously, anything with jump jets and/or oodles of close range weaponry get a nod.

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Re: Urban combat primer - in progress -

Post by Nastyogre » Tue Dec 10, 2013 3:34 pm

Hunchback-G
Most mechs with Jump Jets unless thinly armored with predominantly long range weapons
Jump Infantry
Victors
Crockett/Katana
Enforcer
Motorized Infy
Highlander
Hammerhands
Almost any Mech with piloting skill advances. They can more safely run on pavement and enter buildings without taking damage.

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Re: Urban combat primer - in progress -

Post by motley_jester » Tue Dec 10, 2013 4:11 pm

Sure. Infantry are plain sick in cities. Tanks, especially assault tanks.

High armor, High firepower, low speed units. Osts are generally bad in cities. Hunchbacks good. (although the OTL and OSC's weapons spread are actually decent for city, they spend to much for manuevering that doesn't get used much).

The classics are:
Victors, Battlemasters, Guilotines, Grasshoppers, Hunchbacks Gs and SPs especially, Hatchetmen. Firestarters, Urbiehancocks, all the Jumping bugs, (spiders can be awesome here). Pixies and Enforcers.

Generally, anything with an AC/10 or better AC/20 will do well in city. Combat tends to start around 15 hexes or less, and almost always boils down into a brawl. JJs let you get more meks into the brawl, or past it. LRMs are usually more useful in cities than PPCs because of IDF, except that several of the PPC boats can do well in cities for other reasons. Awesomes are zombies, and have enough heatsinks they can afford to fire on bad numbers close in. I'd rather an ARC than an awesome in a city, but that doesn't mean the Awe is bad there. Whammies have the close in weaponry to handle city fighting, again I'd rather an ARC, but the whammie is good. Still, I don't like PPCs in cities, or any minimum range weapons.

QKDs can shine in city fights, good JJs, and the rear mounted lasers can be useful here. Still not a good mek design, but it does better in urban than open terrain.

(my) Ideal lance for city fighting is an Archer or Longbow (7Q) for long range support, 1-2 solid jumpers, and 1-2 solid tanks. Arc, Guilotine, Battlemaster, Victor. would work. Or Longbow, Atlas, Grasshopper, Awesome. A mix of generalist meks can be good too. Crusader, Stalker, Cyclops, Whammer for instance, should do well. For lighter lances, try Trebuchet, Pixie, Hunchback-G (J or the AC/10 one can work too), Enforcer should play well. Drop the Treb for another enforcer or hatchetman, or put an urbie in to drop the BV some. Gotta be careful though, to low and you run into the bug armies. 4x spiders is going to be a long, and (to me) unfun game.

Generally, don't use fast units in cities. :) Not that they're unusable, but they depend on their speed for defense, and they won't get that speed in a city (or they'll end up falling and skidding). Do beware, if someone has an OTL, expect them to run it down a side street and try to strafe/maul your rear units.

Infantry are worth their weight in gold in the cities. Buildings are cover, plus armor, plus height for spotting, plus obsticles for everything else. Remember, on top of a building == hittable, inside the top floor still gives good view, AND gives cover. Jump infantry can skim the tops of buildings, but mech infantry can go through buildings (while meks have to go over/around). Use infantry to spot, use them to scout, find the basements for your meks to avoid (make hardened buildings a priority! a 100-200CF hardened building is a great shield for many meks, but a basement can ruin it)

Even foot infantry can be useful in a city fight. They're cheap, but they can usually use roads for an extra +1 movement, and being able to move through buildings for 1 MP means they can often cut the chord and get into the fight that takes the meks extra time to move around.

And now to tanks...
Last fight I had in a city was Devastator, Von Luckner, 2x rhinos, 4 infantry (2 hover, 1 wheeled, 1 jump, assault rifles/AC). I took out a LNG-0W, Hunchback-G, OSC, Pixie. I won without losing a unit (though I had mobility hits that slowed me down), he lost 2, and got the salvage on the third. Rhino's did IDF 1/2 the game, then moved into direct support mode once the devastator and luckie got into range. The infantry played tag, getting backshots and head shots to immobile units, by flitting through buildings, staying inside them for coverage. Jump stayed back most of the game for spotting.

Fight before that, 2x behemoths, 2x rhinos, 1 jump infantry, I was mauled. mobility hits took my behemoths to zero movement letting him concentrate on a single side and killing them through internal damage. He had a Guilitine, Catapult, Hata, and CGR-1A9 (I think). It was a brutal and close match. Both rhinos were 100% drained of ammo, he was down to 3 meks but the catapult was red for internal structure (I'd blow both torsos off at that point, no ammo, grrr), hata down, his two functional meks had gapping holes in them. I lost because he used the terrain really well, and his jumpers kept jumping in and out of range, back and forth between behemoths, getting hit to-hit numbers against them, and getting physicals in on me, and I didn't get my infantry into the fight until the very end (and then not close enough to hit well).

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Re: Urban combat primer - in progress -

Post by Klingon » Tue Dec 10, 2013 4:49 pm

c_guenther wrote:Perhaps you could post a list of good urban units.

Obviously, anything with jump jets and/or oodles of close range weaponry get a nod.
The problem, is this can depend greatly on your technique. Jump jets are handy for easy maneuvering, but I find the better armor/weight/firepower that you get for not having jump jets more useful in general.

Some units are obviously good, like the Hunchback or Urbanmech. I'd say lean away from LRMs, but again, that varies by technique. I'd say it makes some units a lot more useful, but makes some others a lot trickier to use. Actually using LRM IDF in Megamek I've generally found to be an exercise in frustration, but that's just me, plenty of folks use it just fine. Maybe someone who knows should put together an IDF primer...?
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Re: Urban combat primer - in progress -

Post by scorpnoire » Wed Mar 16, 2016 12:13 pm

Since such a situation arised just recently I have a very specific question regarding Mechs in Lvl 1 buildings.

In said example an Assault Mech (the japanese named Thug pendent Hatamoto (?)) was placed in a Lvl1 building and suffered from a collapsed cellar, yet still standing.
All my ranged Units still had LOS and since he didn't move I (foolishly) decided to concentrate fire on him.
Result: the shots that hit got plainly absorbed by the building, his Mech was still fine.

Would it, in this specific situation, been better to concentrate fire in the building instead with a sure collaps at the end of the firing phase and thus terminate the Mech by a collapsing building?

Thanks for any helpful answers and sorry for necroposting (again).

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Re: Urban combat primer - in progress -

Post by Nastyogre » Wed Mar 16, 2016 2:11 pm

Depends. If the building had a basement then certainly as a mech that falls into a basement and is then buried is completely destroyed regardless of damage taken by the fall or collapsed building.

Without a basement a level one building is not going to do enough damage to kill an assault unless get a tac crit. Even a level six isn't going to kill a heavy or an assault outright. It might strip a location and inflict a mortal critical hit.

Now dropping the building is going to cause a PSR. A good thing. That assault is a sitting duck next turn. Falls are never fun. The hex would be difficult terrain I think so the stand might be harder.

It's very situational. If there is a one to two level basement, yes drop the building. If there is a building that is low enough CV to have the mech take some damage and drop the building? Do that. If its 3 levels or higher, yeah drop the building. I'd you can't hurt the unit or drop the building and the unit is using the building as a fort, reduce the building and positikn yourself to drop it next turn.

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Re: Urban combat primer - in progress -

Post by scorpnoire » Wed Mar 16, 2016 3:25 pm

Thanks for your reply!
Yes, in my case the mech already crashed into a Lvl 1 cellar beneath the lvl 1 building, but was standing upright and still (but not on top of the building).
Or does the destroyed when collaps rule only comes into play if the Mech is laying in the cellar?
How about salvage in such a case? Would there be a chance?

And a follow up question, this situation is somewhat older.
I had an opponent wich moved a prone(?) ARC into a lvl 3 building (crouched one?)...ARC was prone, after movement he was vanished and opp. confirmed it was in the building.
Even though I had a Mech standing directly next to this building I got no LOS to that ARC.
I had all hexes around the building in LOS too, so no, he was not hiding behind instead.
Is this intentionally? How can I fight such a vehicle in such a case?

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