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Author Topic: Vehicles and Structural Integrity  (Read 627 times)

Daemion

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Vehicles and Structural Integrity
« on: 05 June 2019, 17:33:12 »
I've been playing around with the notion of using Structural Integrity - found in the Aero rules - for Primitive Vehicle designs.  Combine that with armor threshold rules and a 'transmission' velocity system, I think we can get a better representation of modern vehicles.

I'm curious if other people have done this.

Any suggestions on how to apply tonnages? 

Thoughts?
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The_Caveman

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Re: Vehicles and Structural Integrity
« Reply #1 on: 05 June 2019, 19:13:37 »
I've been playing around with the notion of using Structural Integrity - found in the Aero rules - for Primitive Vehicle designs.  Combine that with armor threshold rules and a 'transmission' velocity system, I think we can get a better representation of modern vehicles.

I'm curious if other people have done this.

Any suggestions on how to apply tonnages? 

Thoughts?

Why limit it to primitive vehicles? This is how 31st century tanks should be. One SI point for every 10 tons, round up. Crunchy on the outside, squishy on the inside.

A "transmission" rule is unnecessary, it doesn't take that long to shift gears. But I liked the old BattleDroids rule that vehicles can't shoot while using their full MP (all vehicles had 4 MP and could only use 3 if they wanted to fire). They should lose the attacker movement modifier in exchange, though.
Half the fun of BattleTech is the mental gymnastics required to scientifically rationalize design choices made decades ago entirely based on the Rule of Cool.

The other half is a first-turn AC/2 shot TAC to your gyro that causes your Atlas to fall and smash its own cockpit... wait, I said fun didn't I?

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Re: Vehicles and Structural Integrity
« Reply #2 on: 05 June 2019, 21:20:54 »
Sort of, but my take was a "reverse threshold" where crits were ignored if the armor was 10x thicker than the incoming round.  But that take was more for minimizing the "unlucky TAC from LB-X or SRM gimps your Gyro on turn 1" sort of deal.

As for the "one SI per 10 tons" suggestion, not sure how that'd make any practical difference.  I rarely ever see a vehicle get internal in more than one location before blowing up anyways.

Daemion

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Re: Vehicles and Structural Integrity
« Reply #3 on: 06 June 2019, 10:37:40 »
The fact that it can spread out the damage across the other locations by turning around means it could live a little longer.

With merely one set of IS points to deal with, it doesn't matter what direction the damage is coming from. Should we apply the 1/2 damage modifier that we see with fighter craft?

I'm personally thinking no, because most combat vehicles don't occupy the same volume that a lot of aircraft do, regardless of tonnage. Or, if we do, it's the futuristic standard, and we can use other multipliers for different tech levels.



As for transmission, I was thinking more about safe braking, and that sudden stops might have negative effects on either the motive system, or even see the vehicle flip/roll if it isn't careful. 

Another thing would be if you're tracking fuel consumption, which should be a thing for most ICE and other non-fusion/fission powered craft. It takes extra fuel to get up to speed, but once you're there, it only takes a point to maintain it, barring expenditure for up-hill movement.

I was thinking of using it for primitive support vehicles, mostly, because I can envision a lot of the futuristic vehicles using separate electric motors to actually turn the wheels independent of a single transmission system.


Now, as to armor threshold, I'm thinking that we can see different levels of protection based on material and construction technology.




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Re: Vehicles and Structural Integrity
« Reply #4 on: 06 June 2019, 13:35:22 »
The fact that it can spread out the damage across the other locations by turning around means it could live a little longer.
Let me elaborate.
Of course, having the SI be centralized instead of location based means it can spread out damage better, and thus increase survivability.

What I mean is, in my experience, it usually doesn't make any difference.  The exception being vehicles that are both:
1.Big and heavy
2.Anemically Armored

For instance, for vehicles 10-tons and under like APCs and savannah masters, it simply doesn't matter either way as first internal hit leads to death.

When using a lot of the heavier weapons like Gauss Rifles that deal a lot of damage to one location, a lot of vehicle's survivability is measured in a few hits.  A bog-standard Bulldog will die if it gets hit twice by Gauss in any location, regardless if the IS is split into directions or standardized.  A Galleon dies with one gauss hit in any location except the turret.  Scorpions die to 2 PPC hits to any location, with or without the SI change.

Vehicles that are both heavy and have heavy armor for their size, they can spread their damage through multiple locations and thus benefit from the current setup, but they also tend to lose their motive system and get crits far before their armor wears out, and that causes its own problems.  For instance, if your Heimdall Ground Monitor (352 armor) loses its MP while its right side is facing the enemy, it doesn't take too much imagination to predict which location's armor is getting shed first.

Now, vehicles that are both big and poorly armored, like the Mobile Long Tom or the Shrek PPC carrier, yeah, that'll definitely make them squishier than they already are.  There's not a huge amount of those though, and for the rest of the vehicles for reasons stated above, there will not be much practical change for most vehicles.

The_Caveman

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Re: Vehicles and Structural Integrity
« Reply #5 on: 06 June 2019, 14:01:36 »
Now, as to armor threshold, I'm thinking that we can see different levels of protection based on material and construction technology.

How about: Threshold = Armor / (20 - BAR rating)?

Thus to get a threshold of 5, a BAR2 vehicle needs 73 points of plywood and a BAR10 vehicle needs 41 points of standard armor.
Half the fun of BattleTech is the mental gymnastics required to scientifically rationalize design choices made decades ago entirely based on the Rule of Cool.

The other half is a first-turn AC/2 shot TAC to your gyro that causes your Atlas to fall and smash its own cockpit... wait, I said fun didn't I?

Daemion

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Re: Vehicles and Structural Integrity
« Reply #6 on: 07 June 2019, 09:47:23 »
How about: Threshold = Armor / (20 - BAR rating)?

Thus to get a threshold of 5, a BAR2 vehicle needs 73 points of plywood and a BAR10 vehicle needs 41 points of standard armor.

Do we even have to bother with BAR?

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Every thought and device conceived by Satan and man must be explored and found wanting. - Donald Grey Barnhouse on the purpose of history and time.

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The_Caveman

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Re: Vehicles and Structural Integrity
« Reply #7 on: 07 June 2019, 15:41:32 »
Do we even have to bother with BAR?

It's not a great system, obviously, but it's what we have. If someone has a less kludgey means of representing primitive armor, I'd be happy to hear it.
Half the fun of BattleTech is the mental gymnastics required to scientifically rationalize design choices made decades ago entirely based on the Rule of Cool.

The other half is a first-turn AC/2 shot TAC to your gyro that causes your Atlas to fall and smash its own cockpit... wait, I said fun didn't I?

RifleMech

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Re: Vehicles and Structural Integrity
« Reply #8 on: 09 June 2019, 00:36:15 »
I can see figuring out a SI for vehicles when they're used in space with jump jets. I'm not sure they'd of be of any use otherwise. They just don't go fast enough. Plus the only vehicles fast enough on the ground don't have enough armor to survive crash.

As for primitive armor. In addition to fewer points than standard, you could use its BAR rating. 10 points and under doesn't penetrate. 11 points or more and you roll for a critical hit.

Col Toda

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Re: Vehicles and Structural Integrity
« Reply #9 on: 22 July 2019, 09:35:02 »
Most just use the Support vehicle rules with Cheeserer armor with threasholds of 5 , 8 , or 10 anyways . Using that you can get interesting drive systems ect . ie Electric powered that has a battery but in city limits contact to a road may have short range Tesla coil broadcast power fields to run on .

Daemion

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Re: Vehicles and Structural Integrity
« Reply #10 on: 22 July 2019, 10:04:27 »
I can see figuring out a SI for vehicles when they're used in space with jump jets. I'm not sure they'd of be of any use otherwise. They just don't go fast enough. Plus the only vehicles fast enough on the ground don't have enough armor to survive crash.

That's not the point.  The idea is that you consolidate the internal structure to one value, like on aircraft, instead of having multiple locations. At the very least, primitive tanks and vehicles are open enough on the interior that shots should be able to damage pretty much anything on the inside.  I'm wanting to emulate that nature in combat tanks, that's all. 

You, my friend, seem too stuck on the rules, as they are.  Need to think a little outside the box that's given, look at the parts you're given, and ask if the rules actually make sense, or if you can use something else from inside the rules to make it make sense. And, if not, then go outside the rules.

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Re: Vehicles and Structural Integrity
« Reply #11 on: 22 July 2019, 15:38:40 »
I've tried out something like that.  Centralized internal structure on one location, the body (+ turret locations if applicable).  It worked well enough, didn't cause any significant change.  Though my take was 1 structure for every 2.5 tons, not the 1 per 10 suggested here.

I wasn't really thinking at all about making vehicles to represent modern tanks though.  It was part of a few other changes as part of a framework to allow more decisions in design (Like structure type: Changing to Endo-Steel or Composite, plus a few other things).

But if the goal is to make them act more like modern tanks in terms of the "penetrate once and die" reality, I'm sure you could approximate them using a SI/Threshold system.

RifleMech

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Re: Vehicles and Structural Integrity
« Reply #12 on: 23 July 2019, 05:49:07 »
That's not the point.  The idea is that you consolidate the internal structure to one value, like on aircraft, instead of having multiple locations. At the very least, primitive tanks and vehicles are open enough on the interior that shots should be able to damage pretty much anything on the inside.  I'm wanting to emulate that nature in combat tanks, that's all. 

You, my friend, seem too stuck on the rules, as they are.  Need to think a little outside the box that's given, look at the parts you're given, and ask if the rules actually make sense, or if you can use something else from inside the rules to make it make sense. And, if not, then go outside the rules.

Then why have an Internal Structure at all? ASF don't.

I do just that. If I were to give vehicles an Structural Integrity rating I'd base it on how fast they travel based on AS movement on the ground sheet. If a ground unit has a Flank MP of 16 hexes or less it'd have 1 SI. 17-32 hexes 2 SI and so on. Most vehicles would only have an SI of 1 or 2.

If you just want get hit and die, why not have all combat vehicles roll for penetrative critical hits and support vehicles rolling twice? Three times if the hit exceeds the BAR?





Daemion

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Re: Vehicles and Structural Integrity
« Reply #13 on: 08 August 2019, 15:29:08 »
Actually, I was thinking about being able to print out the stats on a 3x5 card instead of a 5.5 x 8 half-page.  And, fighters do have internal structure;  that's what the Structural Integrity value is for them.  I'd rather one value for the lot, rather than 4 or 5, making vehicles that much different from Mechs. Sure, different armor locations make sense, but not different internal values per side, not on something which is by all intents, open on the inside.

Unless there's been some redesign in futuristic tanks which has them compartmentalized in some fashion.  ^-^

But, your notion that a vehicle merely dies by taking critical hits is an interesting one.  Only have to track the armor, and then you start rolling on critical table(s) once you're through is something I'd considered for vehicles and (ultra-primitive) Mechs at one point, for a larger tactical-level game.

Still, BT weapons are surprisingly destructive.  A fair amount of fiction featuring vehicles has them rolling, ripping apart, the turret going flying, and other destructive means that speak more to structural integrity failure rather than a caved-in side.  And, being able to simply mark off a pip on a single life bar for a tank's internals instead of tracking the internal pips next to the particular location's armor has a certain appeal to me.

Feels about as satisfying as mapping in the damage from Centurion.  :thumbs:


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Every thought and device conceived by Satan and man must be explored and found wanting. - Donald Grey Barnhouse on the purpose of history and time.

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RifleMech

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Re: Vehicles and Structural Integrity
« Reply #14 on: 09 August 2019, 08:42:15 »
Actually, I was thinking about being able to print out the stats on a 3x5 card instead of a 5.5 x 8 half-page.  And, fighters do have internal structure;  that's what the Structural Integrity value is for them.  I'd rather one value for the lot, rather than 4 or 5, making vehicles that much different from Mechs. Sure, different armor locations make sense, but not different internal values per side, not on something which is by all intents, open on the inside.

Unless there's been some redesign in futuristic tanks which has them compartmentalized in some fashion.  ^-^

But, your notion that a vehicle merely dies by taking critical hits is an interesting one.  Only have to track the armor, and then you start rolling on critical table(s) once you're through is something I'd considered for vehicles and (ultra-primitive) Mechs at one point, for a larger tactical-level game.

Still, BT weapons are surprisingly destructive.  A fair amount of fiction featuring vehicles has them rolling, ripping apart, the turret going flying, and other destructive means that speak more to structural integrity failure rather than a caved-in side.  And, being able to simply mark off a pip on a single life bar for a tank's internals instead of tracking the internal pips next to the particular location's armor has a certain appeal to me.

Feels about as satisfying as mapping in the damage from Centurion.  :thumbs:

Fighters have a value not an actual item. There's no "frame" that costs weight with a value for how much it weights. That frame is what you're hanging the weapons and armor from, like a  mech. It makes sense for that frame to be stronger the bigger the vehicle. It also makes sense in a what for the vehicle to be dead when one of the sides fails. The wall goes out and the roof caves in. Especially if there's a turret on top of it.


 :) Glad you like it.  :thumbsup:

Daemion

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Re: Vehicles and Structural Integrity
« Reply #15 on: 09 August 2019, 13:05:41 »
Read your fighter construction rules again. SI is based on a weight value. Your statement even goes against real-world fighter layout. You knock a wing off and the fighter's effectively done, too. If a side takes enough damage, or both sides take enough damage, that turret or roof should cave in, anyway.  That's the same effect of structural integrity failure, since neither side could hold it up anymore, and it wouldn't take all the IS being 'destroyed', to do it.  Heck, you could tie motive damage to SI checks, as well.

If what you're saying is the case, then fighter craft should have not only SI to fail with stressful maneuvers, but IS locations as well.  In fact, they did, in AT1, if I recall rightly.  I'll have to look to be sure I'm right on that. 

So, to give you an example of what I was shooting for, look at the attached. Much easier too work with, in my opinion.  Granted, I didn't construct these off the construction system, as I have no idea what the actual stats for dedicated mechanized infantry transports actually are.  But, I wanted to create a visual.

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RifleMech

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Re: Vehicles and Structural Integrity
« Reply #16 on: 10 August 2019, 03:53:28 »
Read your fighter construction rules again. SI is based on a weight value. Your statement even goes against real-world fighter layout. You knock a wing off and the fighter's effectively done, too. If a side takes enough damage, or both sides take enough damage, that turret or roof should cave in, anyway.  That's the same effect of structural integrity failure, since neither side could hold it up anymore, and it wouldn't take all the IS being 'destroyed', to do it.  Heck, you could tie motive damage to SI checks, as well.

If what you're saying is the case, then fighter craft should have not only SI to fail with stressful maneuvers, but IS locations as well.  In fact, they did, in AT1, if I recall rightly.  I'll have to look to be sure I'm right on that. 

So, to give you an example of what I was shooting for, look at the attached. Much easier too work with, in my opinion.  Granted, I didn't construct these off the construction system, as I have no idea what the actual stats for dedicated mechanized infantry transports actually are.  But, I wanted to create a visual.

But it doesn't actually have any weight itself. And a wall shouldn't cave if because the armor gets damaged. In real life an aircraft won't lose it's wing just because the armor is gone. It'll crash because it no longer has lift but the wing is still there. In Battletech though that wing won't fly off unless the armor is destroyed.

Unless the armor itself is the structure - Which is how Aerospace is done. - the sides shouldn't collapse until the frame is broken. It'd be like taking the sheet rock off a wall and the house collapsing.

AT 1 had more locations to hit but not internal locations. It still has a single value for structural integrity.

Daemion

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Re: Vehicles and Structural Integrity
« Reply #17 on: 12 August 2019, 09:57:31 »
But, structural integrity failure is the wing coming off, or something equally disastrous. You don't lose the wing on a Fighter when the armor's gone. It starts taking internal damage which weakens its structural integrity - hence it has internal structure.  It just happens to be so open that there's no IS tracking.  I do believe that when the SI is damaged, the craft has to make an integrity check or fall apart.  It's been a while, so I'll have to double check. 

You've seen what vehicle frames look like, right? How much of that actually covers the whole vehicle? Usually its just a frame.  The way BT armor is applied, it's actually hard to imagine the armor being the hull, like we get with current MBTs.  It might be the case that they are, but I'm not seeing it with the repair rules.

So, with that in mind, tanks shouldn't have an internal structure where we can track individual points per side.  To cave in a wall, you have to break the structure, right? You can ablate the protective coating (armor) all you want, but as long as the frame is generally untouched, the structure holds.  Vehicles, while not as big as some buildings, are still big boxes.  Even the smallest takes up as much volume as all three torsos and head of a (light) BattleMech.  (Aside: You can't trust the minis.  The Savana Master is effectively a mobile Mech head, and the Gabriel is stated to have a crew of more than one, making that mini too small for what it should be.) So, that's a lot of space for that kind of internal structure.  I imagine there's a lot of open space between the ribs or frame.

Now, you could make an argument for the hyper accuracy of BattleTech targeting systems, which is an argument I'm fond of, and suggest that attacks can easily pick out the support structure with relative ease, thus necessitating the need for IS values.  But, then we need those same values for aerospace, as well.

And, if it turns out the armor is integrated with the structure, like on modern MBTs, then you have an issue, because the two values should be indistinguishable.  But, even if the armor is full of holes, it can still retain its form until a significant impactor wrecks the form, like a physical attack. In that instance, don't you think there should be some sort of structural integrity check?

I do.

The idea of proposing that Vehicles use structural integrity started as a form of simplification of vehicle sheets by getting rid of superfluous internal structure values for each side, while still allowing for something beyond the armor.   In a lot of ways, it makes sense to apply, for consistency, to anything not a Mech. When a Mech kicks a tank, or it's rammed, it makes sense that it should make a 'cave-in' check (structural integrity).  In fact, I'd highly recommend that buildings should be subject to the same kind of check as well whenever they take any damage whatsoever.

Sure, in some ways, it adds an extra step, but it feels natural, and is easy to envision. 

The other direction, while simple, is inconsistently applied.  If tanks have IS, then so should (Fighter) Planes, DropShips, and even Warships.

Aside: In fact, I've taken on a personal project to map out the stock three DropShips so that when they take damage, especially grounded, they can lose whole sections like a Mech, and only lose partial functionality, unless it's something serious, like the center torso (main drive/keel) or head (cockpit/bridge).  It's especially for when a DS is landed, since I envision ground units being able to pick out targets on such a large structure with relative ease in spite of ambient ECM.  The ship can't move while on the ground, so that armor can't protect the entire side that easily.  Just look at the limitations of Mechs and tanks when it comes to armoring?


I hope you see where I'm coming from on this before you go making yet another argument for the need for Internal Structure Values.




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Every thought and device conceived by Satan and man must be explored and found wanting. - Donald Grey Barnhouse on the purpose of history and time.

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RifleMech

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Re: Vehicles and Structural Integrity
« Reply #18 on: 13 August 2019, 03:54:10 »
Which is where there's a problem. In real life a plane can lose its armor/covering and still fly. It can't when the wing structure breaks and the wing falls off. You can't just penetrate the armor and destroy the internal structure. You have to get through the armor first and then the Structural Integrity. And you have to destroy all the SI only damage is halved.


A Vehicle doesn't really need a role to see if the roof collapses if a side goes. Once the IS is gone the vehicle is destroyed. A mech on the other hand keeps functioning. If anything vehicles should be less hampered by IS than mechs or fighters. They're big and open. Even with a role cage (Reinforced Structure illegal to vehicles under game rules) they're still more open then mechs.  A big dent should effect a mechs function or a fighters aerodynamics whether or not the structure is damaged. Myomer should be rubbing against armor plate. Joints/control surfaces get restricted. Lift is reduced. We don't see that though.

Really I think the easiest way to get what you want is to just go with penetrating critical hits.

 

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