Author Topic: Help with Leg Crits  (Read 937 times)

Mechman08

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Help with Leg Crits
« on: 04 October 2024, 13:25:10 »
Got a game day coming up, and while reviewing the rules realized I wasn’t feeling confident about correctly applying hip critical hits.  Would y’all go over the following hypothetical scenario and let me know if you spot any errors?

Relevant rules excerpts from BattleMech Manual:
Pg. 48, “After a hip critical hit, ignore any other critical hit modifiers from previous turns due to damage on that leg (even if this actually reduces the PSR penalty provided by the leg). However, other critical hits applied to that leg on this turn or later still apply.”

“PSR Modifiers: +2 per hip critical hit; this modifier overrides all other critical hit modifiers from that leg. The controlling player must make a PSR at the end of the phase in which the critical hit occurred.”

How the italicized sections interact is what is causing me confusion.

Mech: SHD-2H Shadow Hawk (5/8/3 MP)
Pilot: Murphy “Why Me” Law (G:4/P:5)

Turn 1, Weapon Attack Phase:
After running into a clearing, Murphy’s Shadow Hawk takes an AC/20 hit that destroys the right leg’s armor and goes internal, scoring a critical on his Upper Leg Actuator.  At the end of the Weapon Attack Phase, Murphy must make two PSRs of 7+ (5 Piloting + 1 for damaged upper leg actuator + 1 for 20+ damage).  He rolls a 7 and then a 9, staying upright.

Turn 1, Physical Attack Phase:
Murphy makes a kick attack against a stationary (but not immobile) Hetzer using the Shadow Hawk’s left leg.  Even though this leg is undamaged, the effects of the right leg critical damage still apply.  Therefore, he needs a 7+ to land the kick (5 Piloting + 2 Running + 0 TMM - 2 kicking + 2 upper leg actuator damage).  Rolling 12, the kick hits, inflicting 5 damage (11 damage base from tonnage, halved by actuator damage, rounded down) to the tank.

Turn 2, Movement Phase
Murphy must recalculate his MP due to the damaged upper actuator, losing 1 Walking MP.  New movement profile is 4/6/3.  He runs to escape the Hetzer’s firing arc.

Turn 2, Weapon Attack Phase
…and blunders right into the sights of a Javelin, eating 5 SRMs for his trouble.  One of the SRMs hits the exposed right leg, scoring two crits: the hip and the foot actuator.

This is one of the points where I’m feeling a little iffy.  Murphy will have to make two PSRs at 8+ (Piloting 5 + 1 foot damaged + 2 hip damaged; the hip crit means the + 1 from the previously destroyed upper leg actuator is ignored).  He rolls a 9 and a 6, and falls.  Murphy’s seatbelt check also requires a PSR of 8+, which passes with a roll of 10.

-OR- (after rereading the excerpts a few times, I think this is right interpretation)

Murphy will have to make two PSRs at 7+ (Piloting 5 + 2 hip damage; the hip overrides the other leg crit PSR modifiers, but the foot crit still triggers a second PSR).  Let’s say he misses one and falls.  His seatbelt check would also be a 7+.

Turn 3, Movement Phase
Murphy has to recalculate his movement again.  Hip damage is applied before any other effects, so starting at 5/8/3, Walking MP is halved, rounding up, leaving 3/5/3.  The foot and upper actuator damage then apply, knocking this down to 1/2/3.  He wants to stand up, requiring 2 MP.  This will count as running movement.  The damaged hip means this draws two PSRs at 7+, one for the stand attempt, and one for “running with damaged hip.”  He rolls a 10 and a 7, a manages to stand the mech.

Turn 3, Weapon Attack Phase
Another SRM hits the right leg, scoring a crit on the lower leg actuator.  Murphy again has to roll a PSR at 7+ (Piloting 5 + 2 hip damage; actuator crit triggers the PSR but its modifiers are overridden by the hip crit).  He rolls an 8 and remains standing.

Turn 4, Movement Phase
Recalculating movement again.  Hip knocks 5/8/3 down to 3/5/3.  Upper, lower, and foot knock off an MP each, leaving the Shadow Hawk at 0/0/3.  With no other options for getting out of Dodge, Murphy jumps 3 hexes into some nearby tree cover.  This again draws a 7+ PSR (Piloting 5 + 2 hip damage; other crits overridden by hip damage).  Rolling 7, he remains standing.

Turn 4, Weapon Attack Phase
The Hetzer is back, and its next AC/20 shot eliminates the remaining internal structure of the Shadow Hawk’s right leg (and then some).  The mech automatically falls, and Murphy’s seatbelt check is a 10+ (Piloting 5 + 5 leg destroyed).

Turn 5, Movement Phase
Interestingly, losing the right leg’s dead weight now puts the prone Shadow Hawk at 1/0/3 movement.  Murphy may make one attempt to stand (counting as Walking) with a PSR of 10+.

Corrections, clarifications, and feedback welcome.  Thanks!

Hellraiser

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Re: Help with Leg Crits
« Reply #1 on: 04 October 2024, 14:14:10 »
let me know if you spot any errors?

Relevant rules excerpts from BattleMech Manual:
Pg. 48, “After a hip critical hit, ignore any other critical hit modifiers from previous turns due to damage on that leg (even if this actually reduces the PSR penalty provided by the leg). However, other critical hits applied to that leg on this turn or later still apply.”

“PSR Modifiers: +2 per hip critical hit; this modifier overrides all other critical hit modifiers from that leg. The controlling player must make a PSR at the end of the phase in which the critical hit occurred.”

How the italicized sections interact is what is causing me confusion.

Comments below in RED, and I'm purely going from memory & don't have TW with me to recheck, soooo, take it all w/ a grain of salt as they say.

Quote
Turn 1, Weapon Attack Phase:  Correct.

Turn 1, Physical Attack Phase: Isn't this just +1 for ULA?
Therefore, he needs a 7+ to land the kick (5 Piloting + 2 Running + 0 TMM - 2 kicking + 2 upper leg actuator damage). 

Turn 2, Movement Phase  Correct

Turn 2, Weapon Attack Phase    See below
One of the SRMs hits the exposed right leg, scoring two crits: the hip and the foot actuator.

 make two PSRs at 8+ (Piloting 5 + 1 foot damaged + 2 hip damaged; the hip crit means the + 1 from the previously destroyed upper leg actuator is ignored).  He rolls a 9 and a 6, and falls.  Murphy’s seatbelt check also requires a PSR of 8+, which passes with a roll of 10.

-OR- (after rereading the excerpts a few times, I think this is right interpretation)  I believe this is correct.  All "HITS" count but "Modifiers" are maxed at +2 by a HIP hit.

Murphy will have to make two PSRs at 7+ (Piloting 5 + 2 hip damage; the hip overrides the other leg crit PSR modifiers, but the foot crit still triggers a second PSR).  Let’s say he misses one and falls.  His seatbelt check would also be a 7+.

Turn 3, Movement Phase  I'm not sure, maybe wrong/maybe correct,  I thought the "1/2" was taken from existing speed.  So 5/8, 4/6, 2/3, 1/2  (Same Result)
Murphy has to recalculate his movement again.  Hip damage is applied before any other effects, so starting at 5/8/3, Walking MP is halved, rounding up, leaving 3/5/3.  The foot and upper actuator damage then apply, knocking this down to 1/2/3.  He wants to stand up, requiring 2 MP.  This will count as running movement.  The damaged hip means this draws two PSRs at 7+, one for the stand attempt, and one for “running with damaged hip.”  He rolls a 10 and a 7, a manages to stand the mech.

Turn 3, Weapon Attack Phase Correct

Turn 4, Movement Phase  See Turn 3 Movement above,  I was thinking different order, based on time of damage, but, same result in this case.
Recalculating movement again.  Hip knocks 5/8/3 down to 3/5/3.  Upper, lower, and foot knock off an MP each, leaving the Shadow Hawk at 0/0/3.  With no other options for getting out of Dodge, Murphy jumps 3 hexes into some nearby tree cover.  This again draws a 7+ PSR (Piloting 5 + 2 hip damage; other crits overridden by hip damage).  Rolling 7, he remains standing.

Turn 4, Weapon Attack Phase Correct

Turn 5, Movement Phase Correct
Interestingly, losing the right leg’s dead weight now puts the prone Shadow Hawk at 1/0/3 movement.  Murphy may make one attempt to stand (counting as Walking) with a PSR of 10+.
« Last Edit: 04 October 2024, 21:18:32 by Hellraiser »
3041: General Lance Hawkins: The Equalizers
3053: Star Colonel Rexor Kerensky: The Silver Wolves

"I don't shoot Urbanmechs, I walk up, stomp on their foot, wait for the head to pop open & drop in a hand grenade (or Elemental)" - Joel47
Against mechs, infantry have two options: Run screaming from Godzilla, or giggle under your breath as the arrogant fools blunder into your trap. - Weirdo

Daryk

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Re: Help with Leg Crits
« Reply #2 on: 04 October 2024, 15:36:51 »
I think Hellraiser's analysis is correct.

Mechman08

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Re: Help with Leg Crits
« Reply #3 on: 04 October 2024, 16:52:38 »
Thanks for checking that over for me.  In terms of experience, I’m senior member of my little Battletech group, so I feel a bit of responsibility to maintain an orthodox read on the rules, lol.  These reviews give me some peace of mind.

Also, double checked the BMM: The upper and lower leg actuators are both +1 on PSR, but +2 on kicks.  The foot is +1 on both.

Daryk

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Re: Help with Leg Crits
« Reply #4 on: 04 October 2024, 19:14:50 »
Good work on double checking... that's always a best practice! :)

Hellraiser

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Re: Help with Leg Crits
« Reply #5 on: 04 October 2024, 21:17:35 »
Also, double checked the BMM: The upper and lower leg actuators are both +1 on PSR, but +2 on kicks.  The foot is +1 on both.

Good Catch & Odd that one, I was just assuming a PSR mod is the same but good to know, and why I noted I was purely going from memory, LOL.

PS.  I just realized one of my answers was not in red, so not sure if you checked on that one.
Order of MP changes after T3 Movement.
« Last Edit: 04 October 2024, 21:19:29 by Hellraiser »
3041: General Lance Hawkins: The Equalizers
3053: Star Colonel Rexor Kerensky: The Silver Wolves

"I don't shoot Urbanmechs, I walk up, stomp on their foot, wait for the head to pop open & drop in a hand grenade (or Elemental)" - Joel47
Against mechs, infantry have two options: Run screaming from Godzilla, or giggle under your breath as the arrogant fools blunder into your trap. - Weirdo

Estwilde

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Re: Help with Leg Crits
« Reply #6 on: 20 October 2024, 13:48:38 »
The discrepancy that Mechman posted at the top of their post concerning the BMM regarding the hip crit seems to have snuck through.

BMM pg48
Quote
After a hip critical hit, ignore any other critical hit modifiers
from previous turns due to damage on that leg (even if this actually
reduces the PSR penalty provided by the leg). However, other critical
hits applied to that leg on this turn or later still apply
.

The way I read this, the Upper Leg Actuator crit from turn 1 would be ignored, but the hip and the foot were both damaged this turn, and both modifiers apply. The 2 PSR's would have a +3 modifier (+2 hip, +1 foot), so I think the first choice is correct. (PSR TN 8)

The rationale in TW is that the leg stiffens and locks up (BMM omits this rationale text write up), and I assume is using the thinking that follow up crits just break the leg more after the stiffening.
« Last Edit: 20 October 2024, 13:55:30 by Estwilde »

Mechman08

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Re: Help with Leg Crits
« Reply #7 on: 04 December 2024, 03:35:03 »
The most recent episode of BungleTech had Xotl on, and in the course of the show he mentioned hip crits as being a frequent cause of trouble for players.  Some of the comments made on the show (and Estwilde's earlier post here) made me wonder if I still had it wrong.  While MegaMek isn't necessarily a definitive source for rules judgements, I thought it might be worthwhile to experiment in it a bit.

I setup a test game against myself in MegaMek 0.49.7.  On one side, a Piranha (Standard).  On the other, an Atlas (no LL armor), an Awesome (no LL armor, hip crit), a Battlemaster (no LL armor, upper, lower, and foot crit), and a Banshee (no LL armor, hip and upper crit).  All pilots involved were set to (0/0).  Here are my results after letting the Piranha chew on them a bit.

Atlas (no preexisting crits), MP 3/5
Very first successfully rolled crit chance...12, LL blown off.  We're off to a good start.  :angry:
However, when I tried to stand it the following turn using its MP 1/1, this resulted in MegaMek reporting it as having used Running movement.  Turns out I'd misread BMM p. 19's entry on standing up with only one leg.  This movement counts as running (but doesn't draw any PSRs other than the stand attempt), but once standing the 1/1 hop from hex to hex is counted as walking.  So Turn 5 of my previous hypothetical scenario was incorrect.

Awesome (preexisting hip crit), MP 2/3
Code: [Select]
Machine Gun at Awesome AWS-8Q (Tester);  needs 0, rolls 5 : hits  (using Left Side table) LL
        Awesome AWS-8Q (Tester) takes 2 damage to LL.
             7 Internal Structure remaining.
            Critical hit on LL. Roll is 12;LIMB BLOWN OFF Left Leg blown off.
Oh, come ON!  :angry:

MegaMek's die roller aside, there's an interesting point here.  The resulting seat belt check was at a 7+.
Code: [Select]
Awesome AWS-8Q (Tester) must make 1 piloting skill roll(s) (leg destroyed).
The base target is 2 [0 (Base piloting skill) + 2 (Left Leg Hip Actuator destroyed)].
    Roll #1, (leg destroyed); automatically fails.
     Awesome AWS-8Q (Tester) falls on its rear, suffering 8 damage.
        Awesome AWS-8Q (Tester) takes 5 damage to LL.
        5 damage transfers to LTR.
        Awesome AWS-8Q (Tester) takes 5 damage to LTR.
            5 Armor remaining.
        Awesome AWS-8Q (Tester) takes 3 damage to LL.
        3 damage transfers to LTR.
        Awesome AWS-8Q (Tester) takes 3 damage to LTR.
            2 Armor remaining.

 Pilot of Awesome AWS-8Q (Tester) "Folco Lano" must roll 7 to avoid damage; rolls 5 : fails.
        Pilot of Awesome AWS-8Q (Tester) "Folco Lano" takes 1 damage (1 total hits).
        Pilot of Awesome AWS-8Q (Tester) "Folco Lano" needs a 3 to stay conscious. Rolls 7 : successful!

I expected it to only be +5.  Referring to the chart on BMM p.142, under Damage to Mech I see that "Leg destroyed" is an automatic fall, with footnote #5 stating "The modifier for a destroyed leg is +5 when making a Piloting Skill Roll to avoid damaging the MechWarrior during an automatic fall."  However I missed that the Special Cases: Preexisting Damage modifier for the damaged hip would apply for this phase.

Battlemaster (preexisting upper, lower, and foot crit), MP 1/2
Code: [Select]
Machine Gun at BattleMaster BLR-1D (Tester);  needs 0, rolls 7 : hits  (using Left Side table) LL
        BattleMaster BLR-1D (Tester) takes 2 damage to LL.
             12 Internal Structure remaining.
            Critical hit on LL. Roll is 11; 2 locations.
            CRITICAL HIT on Hip.
            CRITICAL HIT on Heat Sink.

BattleMaster BLR-1D (Tester) must make 2 piloting skill roll(s) (hip actuator hit; 20+ damage).
The base target is 3 [0 (Base piloting skill) + 1 (Left Leg Upper Leg Actuator destroyed) + 1 (Left Leg Lower Leg Actuator destroyed) + 1 (Left Leg Foot Actuator destroyed)].
    Roll #1, (0 (Base piloting skill) + 1 (Left Leg Upper Leg Actuator destroyed) + 1 (Left Leg Lower Leg Actuator destroyed) + 1 (Left Leg Foot Actuator destroyed) + 2 (hip actuator hit) + 1 (20+ damage)); needs 6, rolls 7 : succeeds.
    Roll #2, (0 (Base piloting skill) + 1 (Left Leg Upper Leg Actuator destroyed) + 1 (Left Leg Lower Leg Actuator destroyed) + 1 (Left Leg Foot Actuator destroyed) + 1 (20+ damage) + 2 (hip actuator hit)); needs 6, rolls 7 : succeeds.

So here we see that the preexisting crits to the leg and foot actuators still apply to the phase where the new hip crit occurs.  But then we get to the kick...
Code: [Select]
Kick (Left leg) at BattleMaster BLR-1D (Tester); needs -2, rolls 11 : hits (using Left Side Kick table) LL
        BattleMaster BLR-1D (Tester) takes 4 damage to LL.
             4 Internal Structure remaining.
            Critical hit on LL. Roll is 2; no effect.

BattleMaster BLR-1D (Tester) must make 1 piloting skill roll(s) (was kicked).
The base target is 2 [0 (Base piloting skill) + 2 (Left Leg Hip Actuator destroyed)].
    Roll #1, (0 (Base piloting skill) + 2 (Left Leg Hip Actuator destroyed) + 0 (was kicked)); needs 2, rolls 9 : succeeds.
The hip critical has now become preexisting relative to this phase and, per BMM p.142 footnote #10, it overrides the other preexisting leg crit modifiers.  This overriding effect also means that on the following turn the Battlemaster's MP had increased to 2/3.

Banshee (hip and upper crit), MP 2/3
Code: [Select]
Machine Gun at Banshee BNC-3E (Tester);  needs 1, rolls 10 : hits  (using Left Side table) LL
        Banshee BNC-3E (Tester) takes 2 damage to LL.
             18 Internal Structure remaining.
            Critical hit on LL. Roll is 10; 2 locations.
            CRITICAL HIT on Foot.
            CRITICAL HIT on Lower Leg.

Banshee BNC-3E (Tester) must make 3 piloting skill roll(s) (leg/foot actuator hit; leg/foot actuator hit; 20+ damage).
The base target is 2 [0 (Base piloting skill) + 2 (Left Leg Hip Actuator destroyed)].
    Roll #1, (0 (Base piloting skill) + 2 (Left Leg Hip Actuator destroyed) + 1 (leg/foot actuator hit) + 1 (leg/foot actuator hit) + 1 (20+ damage)); needs 5, rolls 9 : succeeds.
    Roll #2, (0 (Base piloting skill) + 2 (Left Leg Hip Actuator destroyed) + 1 (leg/foot actuator hit) + 1 (leg/foot actuator hit) + 1 (20+ damage)); needs 5, rolls 3 : falls.

So here, the preexisting hip crit modifier is applied (the preexisting upper leg modifier is overridden) AND the modifiers for the newly damaged lower leg and foot actuators are applied.  MP next turn remains at 2/3.  Standing up and running results in...
Code: [Select]
Banshee BNC-3E (Tester) must make a piloting skill check (getting up).
Needs 2 [0 (Base piloting skill) + 2 (Left Leg Hip Actuator destroyed) + 0 (getting up)], rolls 9 : succeeds.

Banshee BNC-3E (Tester) must make a piloting skill check (running with damaged hip actuator or gyro).
Needs 2 [0 (Base piloting skill) + 2 (Left Leg Hip Actuator destroyed) + 0 (running with damaged hip actuator or gyro)], rolls 7 : succeeds.

Conclusion
Attempting to summarize the above results: Within a phase, newly received hip, leg, and foot actuator crits always draw their associated PSR and inflict their modifiers.  The following phase, they become preexisting damage and the leg/foot actuator effects are overridden by any likewise preexisting hip actuator crits.

Static

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Re: Help with Leg Crits
« Reply #8 on: 09 December 2024, 17:34:19 »
Yeah, this rule desperately needs some example text in the rulebook, and I hope it will be reconsidered as we go into the next big rules rewrite. It would be one of very few rules changes you could make without bothering anyone.... probably.