How do *you* build Mechas?
 

I'm thinking of running a game with PC mechsuit pilots with a distinctly eastern-mech approach (the mechas are narratively treated more like an extension of the pilot, rather than a vehicle containing the driver). I would like character development to include a significant amount of mech customization, with most characters having access to stock options (Chainsaw hands? Reinforced core armor? Number of aux Etherium turbines?) and tinkerers have the option to innovate (Rocket pack? Chameleon armor? Electro-arc hands?).

They'll be fighting monsters that are even larger and stronger than they are, making the game -- in theory -- boss fights only.

The technology is cinematic mundane, so I'm not going to worry about kilowatts and load strength. At the same time, I don't want mechas to be entirely stat-driven. If you want to armor up, your mech should be meaningfully heavier. If you want to have an oversized gun, that should entail something beyond having fewer points to spend on ST.

So, how has the forum built its mech systems? I've seen some discussion of Spaceships as a foundation, but its scale seems somewhat larger than what I was thinking of. Thoughts?

Re: How do *you* build Mechas?
 

For mechs with a lot of individuality, I'd build them as mindless Ally vehicles with Controls.

Re: How do *you* build Mechas?
 

Well I think you should consider what sort of skills you are going to require from the pilots. Which again depend on what sort of actions they are going to take.


First off I would ask myself: How important should the pilots abilities be, outside of Piloting skill?

For instance. A mech build like a machine is going to require Piloting and Gunner from the pilot. But lacks proper rules for making melee attacks outside of "ramming". You could use piloting skill to make melee strikes though. Sort of substituting DX, Brawling or Melee weapon with Piloting Skill. Or alternatively making Piloting Techniques. But in the end, the only skill needed by the pilot is a high Piloting skill. This fits many anime-genres where you have teenages who are awesome fighters in the mech, but not outside it.
This does mean all the pilots are going to be pretty similar in regards to combat ability. With the mech's capabilities being the main difference. (Which is why I would suggest making a lot of Techniques).


Alternatively. You might want to let the mechs be more like powerarmour, which just enhance the users abilities. So to make a punch or kick, your pilot needs Brawling or Karate skill. Or to fire a weapon they need Guns not Gunner. This way the character's skills are very important.


I think both systems work. It depends very much of the feel and theme of the game. Do you want the best pilots to be veteran fighters or to be the one with the highest Pilot skill?

Re: How do *you* build Mechas?
 

I've not used it, but David Pulver's article Modular Mecha, Pyramid 3/51, p.23, looks like it'd be what I want for something like this.

Mechas come in three sizes, and the 'standard' mecha has certain features. Quality determines how many more (or less for cheap models) features they have, such as more armour, flight, extra weapons, and so on.

Re: How do *you* build Mechas?
 

When I did my mecha game that included some customization of mecha, I just came up with the numbers I wanted by fiat, without any underlying design system. It was fairly quick and easy, and gave me the exact results I wanted.

For a game with extensive customization, going by fiat would be a little more work, but it will also allow you to more closely control degenerate combinations. Extra aux etherium cores might increase handling less on a scout mecha than they do on a heavy mecha.

So I'd start with a table of chassis types, like this:
and then I'd have a list of weapons and add-ons, along with any special notes: a heavy or medium chassis increases Move by 5 and Hnd by 1 at the cost of HT -2 by increasing extra etherium cores, but Scouts only increase Move by 1 and reduce HT by 1. Or whatever; these numbers are entirely off-the-cuff.

But anyway, that's how I build mecha.

Re: How do *you* build Mechas?
 

You can use Spaceships 4 for Mecha, though they tend to be glass cannons.

Re: How do *you* build Mechas?
 

I'd probably build them by fiat, after looking at the tanks, spaceships, and fighter planes they'd be facing off against. Mecha are either small enough to be considered battlesuits or are suboptimal in terms of engineering, so just declaring what you want is probably best.

Re: How do *you* build Mechas?
 

Upright Mecha are more for style than substance, but horizontal Mecha are another story altogether. A hexapodal Mecha would offer superior functionality when compared to a tank of the same mass in an Earth-like environment, though they would be mechanically more complex. A piscine Mecha would offer superior functionality when compared to a submarine, though they would also be more complex than a submarine. In short, humanoid Mecha are impractical, but animalistic Mecha are promising.

Re: How do *you* build Mechas?
 

How do you figure the spider is better than the tracked tank? When I build a TL 10 T-72 analogue using Vehicles 2nd edition and swap the treads for 8 legs*, ground pressure goes up and maximum speed goes down by 2 mph. Both designs have almost the same off-road speed in most conditions - the spider is twice as fast in forest and swamps, but only because both vehicles are fairly light weight (~15 tons) and that prevents the tank from smashing through trees.

8 exposed legs are a lot more vulnerable than treads. The speed advantage in swamps and forests, and the overall improvement in MR, are rather small compared to the risk of having the legs blown off.

* Each leg had DR 180 advanced laminate armor on all faces, so I didn't skimp on the protection but it's still nothing compared to the tank's front armor.

Re: How do *you* build Mechas?
 

A spider can function with two crippled legs, a tank cannot function with even one crippled tread. Depending on the design, crippled legs are also much easier to replace than crippled treads. In addition, you can lower or raise the body of the spider by adjusting the angle of the legs, allowing for better performance on angled surfaces (and even allowing the body of the spider to remain level despite the angle of the terrain).

Re: How do *you* build Mechas?
 

Haven't read it yet, but you might want to look into One With the Ship from Pyramid #3/30. It has templates for characters that interface with ships, but I would imagine that it would work with mecha.

Re: How do *you* build Mechas?
 

The terrain consists of many small, rocky islands in a dangerous and monster-infested sea. Fighting the monsters in the ocean is suicide, even with a massive battleship, as the monsters can fight entirely submerged while the (dieselpunk) technology can't even detect them until they breach the shallows.

Mecha are small enough to travel by sloop or corvette, and mobile enough to patrol an entire island no matter how steep. Modern designs can ford shallows out to two fathoms, allowing one unit to travel between nearby islands and even finish off a wounded kaiju that has retreated into the sea. And importantly, unlike an emplaced gun, Mecha can be easily moved from island to island and can't be used by a local island to declare independence.

Re: How do *you* build Mechas?
 

High ground pressure, almost certainly higher minimum height, probably wider, with the legs having joints that are exposed and almost impossible to armour (at least tracks are low and close in to the tank...

And as you noted, more complex, which means harder to maintain, and tanks already have a huge maintenance time requirement.

Oh, and that's for a spider-tank vs a tracked tank - 'mecha' traditionally implies a single or possibly two crew, and that means they're most likely massively over-worked.

As for fish-mecha vs submarines - submarines are already fish-shaped. Making them flexible, and/or powered by fins, not props is a technological advancement in the development of subs, not a change from 'sub' to 'mecha'.

Re: How do *you* build Mechas?
 

I wouldn't play mecha games in GURPS, the Vehicles/Mecha rules take too long to design and as a rule of thumb each player needs a different Mecha and you'll want at least that many enemy designs.

Spaceships is faster, but you'll want distinct designs and I don't think spaceships can manage that.

Building by character point (even as Allies) is likely to run into balance issues, because the guy who takes a recon Mecha is going to be spending a lot less points then the guy who wants an artillery Mecha.

If I absolutely had to I'd build them like power armor, just bigger, but after designing all the vehicular weapons of the setting separately.

Re: How do *you* build Mechas?
 

Do multiple mecha using Vehicles 2e take that long to design? I think my first design took two hours or so, and a lot of that was figuring out the sensor and comm suite.

After I had a design, tweaking it to be lighter and faster took about 30 minutes, same for adjusting it to be heavier and slower. That gave me three designs that roughly matched my previous mecha designs. I don't think creating a fourth design would have taken a lot longer.

That's still about 3 times as long as it took me to design and write-up all the designs when I just fiated them. But it's not so long that I couldn't do Vehicles 2e write-ups for a bunch of mecha if that was something I wanted to do.

Re: How do *you* build Mechas?
 

Since you want them to be an extension of the pilot you might want to look at Pyramid 3-24 Biotech. It has bio-mechs that you could take inspiration from and the examples could be used for some of the monsters for them to fight.

Re: How do *you* build Mechas?
 

If everybody is a mecha pilot, then you don't have the problem of balancing characters with mechas against those without. In that case, what I would do is this:

Treat the mecha as a separate character, bought on a separate budget, with no IQ or skills. Don't worry about pricing this as an Ally or Alternate Form or anything: every PC gets the same deal, so the cost is irrelevant.

Furthermore, for the mechas, I would rescale ST, HP, damage, and DR at a factor of 1:10 (D-scale) so a mecha with HP 15 and DR 12 functions as HP 150 and DR 120 when hit with an infantry weapon. If it punches a human with its 1d cr fist, multiply damage by 10. Same goes for the giant monsters.

There are two reasons for this: firstly, the point costs of ST, DR, etc. are roughly balanced against other traits in the human- to slightly-superhuman range, but once you get to three-digit numbers, the balance breaks down. If you've got HT 12, DR 4, and 10 points to spend, buying your HT up to 13 and upgrading your DR to 6 are both valid options. But if you have HT 12 and DR 100, you'd be crazy to buy DR 102 over HT 13, because the marginal benefit of those extra two points of DR is minimal.

Secondly, rolling the dice and doing the arithmetic is a lot easier when the numbers aren't too big. Adding up 30 dice, or even adding up 6 dice and then multiplying by 5, gets old real fast. (I've run a 2000-point supers game. It was exhausting until I started house ruling this stuff away.) It's a lot more convenient to keep the scale manageable.

Re: How do *you* build Mechas?
 

The real problem comes from scaling DR versus Innate Attack. A 2d Crushing Attack costs 10 CP while DR 7 costs 35 CP. Of course, you can combine Damage Reduction with DR to balance things, but you never really catch up. DR 4 with Damage Reduction 4 costs 120 CP, which would get you a 24d Crushing Attack. With an average of 84 HP, your resistance and reduction reduces it to 20 HP, which is better than the 60 HP that would penetrate DR 24, but you are still suffering massive damage with each hit. In effect, GURPS focuses on creating glass cannons that depend on defense, not resistance, to survive attacks (especially when you reach high levels of damage).

Of course, the damage from Spaceships weapons does not scale quite as horribly, but neither does the resistance. Giving vehicles Damage Reduction equal to SM does help though, as the damage from Spaceships scales slowly enough that you stop fighting like glass cannons and start fighting like living creatures, but it is just a house rule. Even so, it is better to depend on defense than resistance.

Re: How do *you* build Mechas?
 

Anyone have recommendations for balancing (and, for that matter, running) combat against the kaiju? I have a clear idea of the level of lethality and the pacing of combat -- I want it to be a tactical puzzle, which means that it will be a bit of a stalemate at first, with a kind of strategic toggle: if you commit to a good strategy, you'll probably win with moderate damage but no casualties. If you instead commit to a poor strategy, you will likely lose a mech and possibly a PC, and that's if you can't escape.

At this point as long as the mecha are reasonably tough compared to humans, they can be any point value, and I have even more flexibility with the kaiju. The first couple combats will feature one sole kaiju, but (naturally) later ones will see two or even three. It's also possible that there will be a mecha rebellion, so the PC mechs may fight NPC mechs... or each other. Those fights will probably be easier to balance and harder to run.

Let's see, other considerations... generally a mecha should be much harder to destroy than it is to disable, with killing the pilot being possible but difficult.

Re: How do *you* build Mechas?
 

In Horror, they deal with kaiju. They treat finding the solution to the kaiju as a unique invention. Combat with a kaiju is difficult because their ST and HP is in the thousands and their DR is in the hundreds (along with Damage Reduction). I would have a small kaiju possess SM+10, ST 2000, DR 200, and Damage Reduction (10). It would kick for 201d+201 crushing damage with Brawling at DX+2 and throw hills 2000 yards for 201d crushing damage.

Re: How do *you* build Mechas?
 

Well, you'll almost certainly want to use D-scale or even C-scale hit points and DR (that is, divide all the relevant values by 10 or 100) - if all the fights are kaiju vs. mecha, the numbers using regular scale are going to just get silly. However, if you do use one of the higher-scale numbers, be aware that damage then becomes much more variable. 100d of damage will vary reliably produce 350 points of actual damage, the average, so 350 DR will reliably stop it, 340 will reliably let 10 through, and so on. But when you switch the scale and start rolling 10d D-damage the odds of it being so reliably 35 points of of damage actually drop, because of the way the probability of dice work. And it's even worse if you use C-scale - sure, the average of 1d of C-scale damage may still be 3.5, but actually, every result (1, 2, 3, 4, 5, and 6) is equally likely to occur.

What I'd strongly suggest is using some variation on the "DR as dice" system. This has been well-covered by Douglas Cole, particularly in "Armor Revisited" in Pyramid #3/34, but the gist of the system is actually quite simple: convert the DR into the number of dice of damage it stops on average, and subtract those from the damage before rolling. To find the average number of dice a given bit of armor would stop, divide its value by 3.5. So, for example, our hypothetical DR 350 mech would stop 100d of damage. A weapon that did 102d of damage would roll just 2d against it, but whatever it rolled would be the amount of damage it took. This system has the advantage of working very well no matter what scale you choose to use: 35 points of d-scale DR subtracts 10 dice from D-scale attacks, and 3.5 points of c-scale DR subtracts 1d from C-scale attacks, which all works out to the same average damage penetrating.

Re: How do *you* build Mechas?
 

A couple of general points from having run a mecha versus giants game, which is conceptually similar but different:

* Precalculate as much as you can. I put together a table of Acc bonuses versus Aiming times after the second session, because people were having problems calculating the bonuses of Acc 6+3 (with a +3 gunnery bonus that kicks in after 2 turns of Aiming) weapons.

* Make a cheat sheet or summary of all the special rules you're using for mecha fights, unless you're just treating mecha as really, really tall humans and using only standard GURPS rules. And even then, you're probably going to increase the map scale to 5 yards to the hex or something, and that's going to affect how people move, and you'll need to think about and create a cheat sheet for those changes.

* Don't use Armor as Dice. I did in my Mecha game and was a mixed bag. AaD is great in concept, but it can be a little confusing in play, especially if you have people shooting APDS rounds through cover to hit their targets. I'd recommend (without having tested it) using minimal variation fixed damage, where you convert all damage over 3d to a fixed value. Instead of dividing DR by 3.5 to convert it to dice, subtracting the armor dice, and rolling damage, you just roll a few dice and add or subtract numbers. So a 7.62mm rifle would do 3d+14, for instance, and if you shoot it through a DR 10 obstacle, it does 3d+4 to it's target. (With armor as dice, you'd have to convert the obstacle to 3d on the fly, subtract 3d from 7d, and roll 4d damage for the target, which can be a hassle in game). Much easier, but it's still low variation so you don't have to worry about a lucky damage roll from a weak weapon blowing through someone's armor.

* I personally find Injury Reduction to be confusing, but you'll have to decide for yourself.


As far as mecha and kaiju design goes:
* If mecha are supposed to be easy to disable but hard to destroy, give them a lot of torso and cockpit armor, but significantly weaker armor on the limbs. Kaiju will be incentivized to dismember them instead of wrecking the torso or cockpit and destroying them.

* Kaiju should not be doing nearly enough damage to one-shot a mecha, or even take off a limb in a single attack. If it's a puzzle battle, the PCs are going to need some time to figure out what works and what doesn't, and that won't happen if a PC mecha is going down every time a kaiju attacks.

* Kaiju should be nigh-invulnerable to mecha weapons, aside from weak points/tactical considerations. PCs shouldn't expect to be able to grind a kaiju down without doing something clever. Conversely, almost any attack at their weak point should succeed, and should give immediate feedback that the kaiju was badly hurt and the PCs should try to repeat that attack. Except for evolving kaiju, of course, where the puzzle is to keep coming up with new attacks, but for those kaiju, you want the kaiju to react and then cover up it's weakness.

I'm not sure what numbers I'd use for the kaijiu and mecha, and to a large extent, it doesn't matter what the actual values are. As long as the two sets of numbers are appropriately scaled, you should be fine.

Re: How do *you* build Mechas?
 

I would suggest building mecha as characters, not equipment, but you'll be operating in a range where GURPS character building has issues, so I recommend an advantage along the lines of:
Mecha-Scale
You're functioning on the scale of mechs, rather than humans. As long as you are fighting other mechs, use the normal GURPS combat rules. If for some reason you have to interact with non-mech-scaled opponents, make the following adjustments:

• Base SM is <X>. Set <X> to a value that matches common mechs in the setting -- for example, <X> is +4 for Macross (9 meters) while it's +10 in Pacific Rim (80 meters).
• Any powers that reference hexes actually function in scale hexes. To determine the size of a scale hex, look up <X-2> on the range/speed chart. Thus, a Macross hex is 5 yards.
• Any powers that reference time function in scale time units. Scale time units are optional, but having the giant monsters function on a 5-10s turn can be useful for PC survivability when they're out-of-mech.
• Any powers that reference pounds actually function in scale pounds. To determine the size of a scale pound, multiply by 10 for each +2 to <X>, and if <X> is an odd number, multiply by 3. Thus, a Macross pound is 100 lb.
• When interacting with human scale targets, giant robots have a DX penalty of <X>. This includes attack rolls. However, giant robots also measure range penalty based on scale hexes (alternately, ignore the first <X> in range penalties).
• Damage, Damage Resistance, and Hit Points are all measured in scale hp. Don't try to come up with formulas based on SM, just pick a scale that works well. D-scale works fairly well for smaller mechs that are supposed to be at least somewhat worried about humans, kaiju might be C or M scale.
• To balance innate attack against DR and melee attacks, innate attacks are limited to (Swing) dice of damage.
• Exact point value of all this is irrelevant, as it's a setting switch -- when you're in a mech, you have mech-scale abilities.