Are buildings deathtraps?

[Marasmusine]

Hello, I had my first AS game today with battle armour, and I did what seemed intuitive for infantry and moved them into buildings: most games give good defensive bonuses for infantry in buildings.
This seemed to be a mistake, the default CF for medium buildings is 3 or 4. Buildings are immobile, so very easy to hit. A single mech collapsed the building in one attack. Battle armour inside is instantly destroyed.
So it's better to have infantry just out in the open?

What's confusing is the example on p 74:

For example, if a unit capable of delivering 5 points of damage strikes a CF 4 medium building with an infantry unit inside, the building applies the 5 damage to its CF and is destroyed . The same attack is also applied against the infantry: 5 points of damage from the attack, minus 2 for a medium building’s damage absorption for infantry . The infantry takes 3 damage from the attack .

If the building is destroyed, why go on to the step of applying the attack to the infantry, if the infantry is destroyed by the collapsing building anyway?

Am I missing something?

[Lanceman]

Because not every building has such a low CF. You don't want your infantry to huddle down in a building that's going to be blown apart by a mech in one go, you want to hide them in a heavy or hardened building that can stand up to incoming fire and absorb most of the damage from getting to the infantry unit. Putting infantry in a medium building is like running into a Walmart hoping it will protect you from a JDAM.

That being said, with the way damage is dealt in Alpha Strike by default, buildings aren't quite as useful as they are in Classic, where an infantry platoon in a heavy or hardened building become a real problem.

[Marasmusine]

Ah, I was using "medium" buildings because that's what represents most cityblock buildings.
I was using the "average" CF, but the building models I have are multi-story blocks, so I could go up to the maximum of CF 6.
Are there any other interactions with infantry/buildings?
For example, destroying a building to turn it into rubble and have the infantry go in the rubble? I can't see any rules that would make that an advantage.
Infantry can also "dig in", but they can do that in most terrain anyway including "Clear".
(I'm used to playing OGRE, where battle armour infantry get a good defensive bonus for being in towns or rubble.)

It's also funny that "light" structures includes "tents". You could have a battle armour squad in a tent, and then be destroyed by the collapsing tent :)

[Lanceman]

That's about it for buildings, but conventional infantry can use the Digging In rules to dig into any terrain that isn't pavement, buildings, or water for an additional +2 to hit modifier. Rubble in Alpha Strike is basically treated as artificial rough, so doesn't convey any additional modifiers the way woods or planted fields do. You can also use engineering infantry or vehicles to create fortified positions on any terrain but buildings and water that provide the same bonus that infantry just have to move into (and tanks and ProtoMechs can use them to go hull down).

While the book defines most city buildings as medium, don't be afraid to throw some heavy buildings in there as well, that represent large apartment blocks, skyscrapers, etc. With a maximum CF of 18, they'll be much more useful for infantry units. But even a CF6 building is going to help protect an infantry platoon from light mech fire, just remember to get out before the building comes down. Use infantry's ability to move through buildings with no additional movement modifiers to keep going down the block.

As for the last bit, I know the image is funny, but just remember it's an abstraction for gameplay purposes. A light building collapsing may not "kill" the platoon/BA squad for the purpose of a campaign, but it does render them combat ineffective for the remainder of the scenario at hand as they extricate themselves. "Tent" here is going to be more like a large FOB tent instead of like individual camping or pup tent.

[Marasmusine]

Okay, thanks for the info Lanceman!

[MetalEd]

edit:  nevermind.. I've been playing it wrong.

Yes, they seem to be deathtraps.  -4 Immobile means they're nigh impossible to miss.

[phantom16]

I'm still not convinced buildings are worth going in for infantry, even if the building doesn't collapse in one turn. One big shot will still kill any weaker infantry.

If I had a Achileus Light Battle Armor with 3 life and 1 TMM and STL, for an average mech at medium range to hit it, (if I got this all right) it would be skill 4 + range 2 + TMM 1 + BA 1 + STL 1 = 9s to hit, which would likely take several shots before he goes down.
However, if I park that same BA in a building at medium range, now it's skill 4 - Immobile 4 + range 2. It's an automatic hit on a building at medium (or close) range. Yes, the building would absorb some damage (attacking units inside buildings), let's say 2 for a medium building. But that means the enemy only needs to shoot the building with 1 mech that can deal 5 damage at medium range, and it's instantly dead, guaranteed.
I get that it will make them impervious to lighter mechs with 2 or less damage, but now only 1 big hitter has to shoot, and there's not even a chance of the BA surviving. One could make the argument that now the strong enemy is not shooting mechs, but a guaranteed loss still doesn't sound palatable to me.

Am I understanding this correctly?

[Lanceman]

You are.

Part of it just comes down to not choosing medium or light buildings for cover. I wouldn't do it in classic most of the time, and not in AS, especially because infantry in AS take damage in the same manner as other units. If you've got a heavy or hardened building as an option the calculus changes a little bit.