Thursday, April 11, 2019

Battlesuit Design


This popped in my head when I saw this thread on the GURPS forum, and I decided to resurrect my long-dead blog for it (I originally planned to do so by hijacking it for things I’d worked out for the DF-ish setting I’ve been working on recently, but all that still needs some work and this was comparatively simple to make).  As with the previous entries in this blog, this first part has all the calculations, justifications, and so forth - scroll down to Implementation for the final rules.  This wouldn’t be a proper Overhaul if I didn’t overdo things, so these rules can also be used for designing cybernetic limbs or giant mecha.  I feel I should preface this by stating I find it more appropriate to have power armor add to Basic Lift rather than directly to ST, with ST calculated from the new BL.  If you prefer adding straight to ST, build the armor for someone with ST 10, then have the same bonus to ST apply to everyone.  Under this system, the +25 lb BL power armor I’ll be using for examples here would instead just be a straight +5 ST.

When considering a system for building power armor statistics, it seems to me it would be appropriate to look at biology - or at least, biology as it works in GURPS.  A standard GURPS human has ST 10 and is around 150 lb.  A healthy human is typically around 30-40% skeletal muscle and 15% skeleton by weight - we’ll go with 30% for the muscle, for 45 lb and 22.5 lb, respectively.  The reason we include the skeleton is because any muscle system needs some sort of scaffolding to work off of.  Biotech suggests that the above skeleton could actually support up to ST 12.  However, we’re working with an exoskeleton, which are typically less efficient than endoskeletons, so we’ll ignore that.  ST scales with the cube root of weight, while BL scales with the square of ST, meaning our power armor’s BL is going to scale with the 2/3 power of muscle weight (as we would anticipate from the square-cube law).

From this, a theoretical suit of power armor made of living muscle and bone would be designed as follows.  Take the BL bonus, cube it, take the square root, and finally divide by 2.  This tells you how much muscle weight is needed - use half this value for the weight of the bone scaffolding.  For +25 lb BL power armor made in this way, muscle weight would be 62.5 lb and bone weight would be 31.25 lb.

You may notice that the increase to BL is apparently insufficient to offset the weight of the exoskeleton.  However, a properly designed suit of power armor supports its own weight, in the same way a human’s muscles and bone support his weight.  Multiply the combined BL of character and power armor by 7.5 to determine the full weight - including that of the character, suit, and any carried gear - the combination can support.  Any weight in excess of this counts as encumbrance; any weight less than this functionally gives the character something like an external payload.  An otherwise-naked standard GURPS human (BL 20, weight 150 lb) wearing the above muscle suit would have a nominal comfortable weight of 337.5 lb, yet the combination would only weigh 243.75 lb, for a “free” payload of 93.75 lb.

Optionally, underweight character+armor combinations can actually make the character faster.  Based on P=Fv (P=power, F=force, v=velocity), speed would scale linearly with the BL-to-weight ratio (BL should scale linearly with power).  My Mass and Volume Overhaul had every +20% to Move correspond to a +1 to skills that are penalized based on encumbrance.  I don’t feel this is appropriate for power armor, but a bonus to DX-based uses of Battlesuit skill wouldn’t be out of the question.  Our naked man running around in a muscle suit would have a Move of 5*(45/243.75)/(20/150)=6.92, which I’d round up to Move 7.  This is +40% to Move, so a bonus of +2 to Battlesuit skill could be justified.  Optionally, if you feel the armor shouldn’t make the character absolutely faster, treat the boost as Enhanced Move (so it’s only available when sprinting) and Super Jump only.

Of course, an actual suit of power armor isn’t going to be made of meat.  For such, you would divide the muscle weight from above by how much stronger the synthetic muscle is than human muscle.  Looking up some current attempts at making synthetic muscle, I’m getting powers anywhere from 3x human muscle to 200x human muscle, meaning nearly any multiplier is justifiable.  I’d go with 5x at TL9, 10x at TL10, 20x at TL 11, and 50x at TL 12.  Our reference +25 lb BL power armor can thus reduce its muscle weight to a mere 6.25 lb at TL 10.  As the muscles are ridiculously light, I suggest making them with fairly low density.  For no appreciable size increase (so that armor is normal weight), an SM+0 battlesuit can give up to +35 lb BL at TL9, +60 lb BL at TL10, +90 lb BL at TL11, and +150 lb BL at TL12.  Increasing volume allows this to improve - every +5% armor weight is +5% to MaxBL.  Beyond BLx6 (x14.7 to muscle weight), you’re piloting a mecha rather than wearing a battlesuit!
(Realistically, BLx2 is probably the largest a “true” battlesuit can get, with a sort of transition between battlesuit and mecha from BLx2 to BLx6, but a hard cutoff works better for GURPS)

The scaffolding of an actual suit of power armor similarly isn’t going to be made of living bone.  Steel seems likely, but is actually a fairly poor contender when it comes to weight, as living bone is roughly 5x stronger than steel.  The strongest currently known material is graphene at around 200x stronger than steel (40x stronger than living bone).  Diamondoid is essentially graphene, so that gives us our TL11 structural material.  The most common titanium alloy, grade 5, is around 1.5x stronger than living bone, and is probably appropriate for what Spaceships calls Light Alloy (TL7).  This doesn’t quite give us an SSR-linear progression, but it would probably work OK to use a divisor of 10 at TL9 (advanced metallic laminate), 20 at TL 10 (nanocomposite), 50 at TL 11 (diamondoid), and 100 at TL 12 (exotic metal laminate).  Our reference +25 lb BL power armor can thus reduce its structural weight to a mere 1.5625 lb at TL10.  This reduces the total weight of our reference power armor to a mere 7.8125 lb.

Not all power armor is created equal - many give different bonuses to Striking vs Lifting ST.  You may designate extra pounds of BL that apply to only Striking or Lifting ST, at half normal weight for the muscles.  For simplicity, assume the same volume as an equal weight of normal synthetic muscle.  For the scaffolding, Striking ST needs more support than Lifting ST, for a 70/30 split there.

A suit of power armor consumes energy while powered up.  Assume a suit of power armor outputs Watts equal to 5xBL.  This is roughly what a human of comparable strength would output as useful energy if working at a rate that drained 1 FP every hour (say, rowing a boat at travel speed), which is probably a fair enough average for power armor in active use.  How much energy input it requires is going to be a function of efficiency, which would scale by TL.  lwcamp’s “Burninators” has such a scaling hidden in it - 30% at TL9, 50% at TL10, 70% at TL11, and 100% at TL12.  That doesn’t sound too horrible, so we’ll go with it.  To my knowledge, there’s no official energy content for UT power cells, so I’ll just pull the values from my rough Vehicles to Spaceships conversion.  This means for E cells and larger (20+ lb), you’re looking at 2 kWh at TL9, 3 kWh at TL10, 5 kWh at TL11, and 7 kWh at TL12.  D cells and smaller (5- lb) store half as much energy per pound; one assumes there’s some transitional effect in play with power cells between 5 and 20 lb.  Sticking with E-cells and larger, and factoring in efficiencies (and scaling to SSR), that’s a net output of 700 Wh/lb at TL9, 1500 Wh/lb at TL10, 3000 Wh/lb at TL11, and finally 7000 Wh/lb at TL12.  An E-cell lasts for 150/BL hours at TL9, 300/BL hours at TL10, 700/BL hours at TL11, and 1500/BL hours at TL12.  Our +25 lb BL power armor would last 12 hours on an E-cell at TL10.

Once you’ve built the exoskeleton and determined what sort of power supply it needs, now you need to actually armor the thing.  I suggest using the Armor Design articles from Pyramid to do so.  Built-in accessories and similar modifications (Sealed, Waste Relief System, Air Tank, etc) are extremely common for battlesuits.  Most battlesuits are designed so that the weight of the exoskeleton, armor, accessories, and the power supply work out to 7.5x the BL of the suit, so that it perfectly eliminates the encumbrance it creates.

The most common optional accessory for a battlesuit is likely biomedical sensors, in large part because the sensor system needed to detect and translate the user’s movements into those of the battlesuit can be easily modified to function as such.  The price and weight of the default sensor system is included in the price of the muscles, modifying it to function as biomedical sensors is only $100.

All that’s left at this point is cost.  The scaffold is probably around 5x the cost of the material (roughly something akin to Plate construction), and the armor and various accessories are already set from the books and articles.  The problem is the synthetic muscle, which I have no good way of estimating an appropriate price for.  I’m going to try a not-so-good way, however.

TL9 Powered Combat Armor gives +10 to Striking and Lifting ST, or +60 lb BL in my system.  Its synthetic muscles therefore weigh 18.4 lb.  It has DR 70 on the Chest and Skull, DR 50 elsewhere.  Assuming +20% to weight due to increased bulk, and assuming titanium nanocomposite with plate construction, the armor portion should weigh around 138.3 lb and cost $172875.  The suit also has biomedical sensors ($200, 0.2 lb), a waste-relief system ($500, 1 lb), tactical ESM ($1000, 2 lb), a filter mask ($150, 0.5 lb), GPS, hearing protection ($50), a small radio ($50, 0.05 lb), a small laser comm ($400, 0.5 lb), hyperspectral sensors ($2000, 0.6 lb), and a large air tank ($200, 10 lb).  It is sealed ($128.10) with vacuum support and climate control (LSS; $1000, 2 lb) and IR cloaking ($1921.5, 76.86 lb).  Altogether, that’s $180,294.60 and 250.41 lb, with only the weight of the synthetic muscles in play.  Unfortunately, even without accounting for the price of the synthetic muscles, it’s over twice as expensive and around 85 lb heavier than the armor in UT.  Of course, Powered Combat Armor isn’t made of titanium nanocomposite (the first armor design Pyramid article was years away when UT was written), but more likely whatever TL9 combat hardsuits are made of.  Including a helmet scaled up to DR 50/30, those would be around $14050 and 41 lb without all the accessories.  That’s around $350/lb and a W of 0.053 when already taking into account the effects of construction.  Made of that wonder material, the armor portion of our battlesuit would be 76.35 lb and $26723.13, for a total of $34142.73 and 188.46 lb.  Interestingly, not increasing surface area by 20% would give a result of around 163 lb, almost identical to the 165 lb in UT.  If we leave out the surface area boost, we’re looking at $29368.625 and 163 lb.  That means the synthetic muscles cost $60631.375, which we’ll round down to $3000/lb.  That’s for TL9 synthetic muscle.  TL10 synthetic muscle is $7000/lb, TL11 synthetic muscle is $15,000/lb, and TL12 synthetic muscle is $30,000/lb - but as each +1 to TL is around -2 SSR to weight, this means synthetic muscles of equal BL cost roughly the same at each TL.  To allow lower TL materials to be competitive at higher TL, reduce price/lb by -1 SSR per TL after introduction.  Because muscle weight will almost always be a small fraction of a battlesuit’s total weight, expect battlesuits to have the lowest TL muscles necessary to get the desired BL for their volume.


Implementation

Effect of TL:  Many of the equations below include a value, T, which is based on the TL of the material/device.  Note a single battlesuit can have different parts with a different value for T - a TL12 battlesuit might use cheaper TL10 synthetic muscle, a titanium alloy scaffold, and a TL12 power supply.  T is 1 for TL9, 0.5 for TL10, 0.2 for TL11, and 0.1 for TL12.

BL vs ST:  The below designs battlesuits as having their own BL score.  When worn, add the BL of the character and that of the battlesuit to determine actual BL.  To calculate effective ST, multiply the combined BL by 5 and take the square root.

+ST:  Optionally, if you prefer your battlesuits function like those in UT (simply adding to ST), design them as though they were for a character with ST 10.  A +5 ST battlesuit is designed as +25 lb BL, as a character with ST 10 (BL 20 lb) would need +25 lb BL to increase to ST 15 (BL 45 lb).

Muscle:  The first step for designing your battlesuit is to set how much it increases BL.  Once you have done so, you can calculate muscle weight based on the TL of the battlesuit.  To determine weight in lb, use the following equation: (T/10)*S^(3/2), where S is the suit’s BL.

Volume:  A strong battlesuit may make a character functionally larger, making the suit more expensive to armor.  The maximum bonus to BL is +35 lb BL at TL9, +60 lb BL at TL10, +90 lb BL at TL11, and +150 lb BL at TL12.  Every +5% to BL beyond this is +5% to armor weight, to a maximum of +500%.  Any larger than this, you are piloting a mecha rather than wearing a battlesuit.

Striking vs Lifting:  Optionally, you may add additional muscle mass that only adds to Striking ST or Lifting ST.  To do so, design a musculature with the desired total BL bonus.  Subtract the weight of your base musculature, halve the remainder, and add it to the weight of your current musculature to determine the actual weight.  For purposes of Volume, above, treat such specialized musculature as the same volume as an equal weight of general synthetic muscle.

Price:  TL9 synthetic muscle is $3000/lb, TL10 is $7000/lb, TL11 is $15000/lb, and TL12 is $30000/lb.  A given synthetic muscle material is -2 SSR per +1 TL after introduction (TL9 synthetic muscle costs $1500/lb at TL10, $700/lb at TL11, and $300/lb at TL12).

Scaffold:  The scaffold represents the rigid bars the muscles attach to.  To determine its weight in lb, use the following equation: (T/40)*S^(2/3).  TL9 is for titanium nanocomposite, TL10 is for advanced polymer nanocomposite, TL11 is for diamondoid, and TL12 is for hyperdense.

Striking vs Lifting:  If you add additional muscle mass that only adds to Striking ST or Lifting ST, it still needs support.  Striking-only muscle requires 70% as much support as normal muscle, Lifting-only requires 30% as much support as normal muscle.

Lower Tech:  Note you can use lower tech materials here if desired (or if you feel the above is too generous).  To do so, divide tensile yield strength of the material (in MPA) by its density (in g/cc).  Divide 1300 by this number to find T.  For example, grade 5 titanium alloy has a yield strength of 880 MPA and a density of 4.43 g/cc, for a yield/density of around 200 and a T of 6.5.

Price:  Titanium nanocomposite is $1250/lb ($300/lb at TL10+), advanced polymer nanocomposite is $250/lb ($125/lb at TL11+), diamondoid is $250/lb ($125/lb at TL12), and hyperdense is $250/lb.  For other materials, assume the price is the same as plate armor of equal weight (so, 5x the nominal price per pound).

Power:  A battlesuit requires a power supply to function.  To determine how many hours an E cell will last, use the following equation: 150/(T*S).
Striking vs Lifting:  For battlesuits with higher Striking or Lifting BL, count the bonus at half value.
Power Plant:  Some battlesuit designs might have a built in power plant or connect to some other power-generating device rather than relying on energy cells.  Such a power plant needs a usable energy output of 5*S Watts.

Control:  Controlling a battlesuit requires a series of built-in sensors that detect how the user is attempting to move so the suit can move in the same fashion.  These are included in the price of the synthetic muscles.  However, battlesuits also require a Complexity 1 program to run diagnostics on the suit and prevent unsafe movements, so at a minimum the suit must have an integral Complexity 1 computer, typically imbedded in the Chest.  Most have computers more advanced than this to run other programs as well.

Armor:  Battlesuits other than exoskeletons are usually heavily armored.  Such armor is typically built-in, but can be designed to be attached instead as a feature (no effect on cost/weight).  Design battlesuit armor the same way you design armor for a person of the same height.

Scaffolding:  Armored battlesuits may not require separate scaffolding, as the muscles can attach to the armor itself.  If the armor weighs at least 4x as much as scaffolding of the same material would, you may ignore the need for scaffolding.  If the armor has different DR values for the arms, legs, and torso, work out if it would be heavy enough if it were all the same DR as the lowest value.

Accessories:  Any and all standard armor accessories are available for battlesuits, and in fact are more prevalent amongst them than amongst lesser armors.  Biomedical scanners can be added for no increase in weight and only $100, replacing the normal sensors used for controlling the suit.

Optional Rules

Yo Dawg, I Heard You Like Battlesuits…:  Mathematically, it is more efficient by the above rules to design a weak battlesuit, put a weak battlesuit on top of that, and a weak battlesuit on top of that, rather than simply designing a single strong battlesuit.  This is a limitation of the model, not a legitimate way to do the design process!  If you find this limitation problematic, build a suit that has the same BL as the character, then build a suit that has the desired total BL.  The actual weight of the suit is the difference between the two.

Battlesuit Weight:  Battlesuits typically weigh far less than they could support.  A character in a battlesuit can support weight equal to 7.5xBL before encumbrance can start to come into play.  Subtract this number from the character’s full weight (that is, weight of character, battlesuit, and anything carried) before calculating encumbrance.

Underweight:  If the above is a negative number, the battlesuit has power to spare, making it faster.  Divide the current BL-to-weight ratio by that of the character when he is naked.  Multiply Land Move by the result.  Every +20% to Move also gives a +1 to DX-based Battlesuit skill (including for purposes of determining maximum skill level for other skills).  The maximum boost is x2 Move and +5 Battlesuit, but use the full calculated multiplier when jumping.

Partial Battlesuit:  Instead of a full battlesuit, you can design one that only covers one limb.  Determine the needed weight for musculature and scaffolding for a full battlesuit of the desired BL.  If this is no more than 50% of the character’s BL, each full arm+hand is 15% of this weight, each full leg+foot is 20%.  If it is more than 50% of the character’s BL, each limb is 25% of this weight, with power arms covering part of the chest, power legs covering part of the abdomen.

Arm ST vs Leg ST:  A battlesuit can be designed to have boosted Arm or Leg ST, rather than (or in addition to) general boosted Striking/Lifting ST.  Designing this basically follows the rules for the Partial Battlesuit, above.  Arms don’t have to be boosted symmetrically, but legs do.  Arm ST determines damage from hand weapons and how much you can lift at a time, Leg ST determines damage from kicks and encumbrance (which can influence movement and jumping).

Scaffolding Options

Scaffolding as Armor:  It is possible - sometimes probable - to strike the scaffold in combat.  Most crushing and cutting attacks will always strike the scaffold, and it gives 1/6 protection against impaling, piercing, and tight-beam burning.  More diffuse attack types (like burning and corrosion) ignore the scaffold.  When struck, treat the scaffold as giving DR equivalent to plate armor of 4x the weight.  Optionally, if the scaffold is struck and its DR is penetrated, roll against HT, or HT-5 if the penetrating attack dealt damage of at least twice the scaffold’s DR.  On a Failure, that section of scaffolding is damaged, halving the BL of the affected limb until Minor Repairs have been performed.  On a Failure by 5 or more, or any Critical Failure, that section of scaffolding is broken, crippling the affected limb until Major Repairs have been performed.  Damaged/destroyed Chest scaffolding affects one arm, while damaged/destroyed Abdomen scaffolding affects one leg (in either case, decide randomly).  Note the scaffold doesn’t extend to the head.

Armor as Scaffolding:  As a corollary to the above, armor of sufficient strength can replace scaffolding, as the synthetic muscles simply attach to the armor rather than a dedicated scaffold.  Armor must be 4x the weight of the necessary scaffolding of the same material to qualify.  If also using Scaffolding as Armor and allowing for damage to the scaffold, crushing and cutting attacks that penetrate the armor’s DR can break the scaffolding as normal, and impaling/piercing/tight-beam burning attacks have a 1/6 chance of being able to have such an effect.

Endoskeleton:  A battlesuit can be designed to have the scaffolding on the inside, typically right up against the wearer.  This is more efficient - the scaffolding is only 20% normal weight.  This is actually a bit more difficult to design - scaffolding is a net 50% normal cost.  For balance, assume this option isn’t available unless Armor as Scaffolding is available.  If allowing for damage to the scaffold, an endoskeleton’s musculature is susceptible to damage - while it is too diffuse to be affected by impaling, piercing, and tight-beam burning, other attacks will damage it normally.  The musculature has total HP equal to 6 times the cube root of weight in lb, and limbs are crippled as normal for a character (damage to the Torso can be ignored).  Endoskeleton battlesuits are easier to conceal than exoskeleton ones, so a lower LC may be appropriate.

Cybernetics:  Instead of a worn suit, the same design process can be used to replace missing limbs.  Use an endoskeleton scaffold (see above) even if such are unavailable for battlesuits.  Determine the needed weight for musculature and scaffolding for a full battlesuit of the desired BL.  If this is no more than 1.5x the BL of the character, each full arm+hand is 15% of this weight, each full leg+foot is 20%.  If endoskeleton battlesuits are available, you may combine a cybernetic limb with a partial battlesuit to exceed the 1.5x BL limit.  In all cases, the cybernetic limb uses only its own BL to determine ST.  Each cybernetic arm requires a C2 program to control, while one or two cybernetic legs require a single C1 program to control.

Mecha:  Instead of a worn suit, the same design process can be used to design a piloted mecha.  Minimum size for a mecha is x6 armor weight, which corresponds to x2.45 to height (between +2 and +3 to SM).  Use an endoskeleton scaffold (see above) even if such are unavailable for battlesuits.  A mecha uses only its own BL, as the pilot is unable to contribute.  A single C3 program can fully control a mecha, run diagnostics, and so forth.

Sight:  While battlesuits can get away with a visored helmet (or, technically, no helmet at all), mecha typically require a video camera wired to an internal screen (or the HUD of the character’s helmet).  Any of the cameras from UT will work, but note unless the system is capable of 3D recording and displays, the character will function as though he had the One Eye disadvantage.

Speed:  For mecha lighter than 7.5xBL, divide weight by BL and multiply by 1.25 to determine Move.  Optionally, apply +(Move-5) to Hnd.  For mecha heavier than 7.5xBL, treat as having Move 5 and count weight above 7.5xBL as encumbrance.

Controls:  A standard control station for a mecha is a cramped seat with hand (and possibly head and foot) controls, and costs $1000.  Some mecha instead have a special supported bodysuit that allows the character to move around, his movements replicated by the mecha (and with safe force-feedback from the mecha).  This allows the character to control the mecha with Battlesuit skill, and reduces the Complexity of the controlling program to C1.  Such bodysuits cost $3000.  A mecha can also be designed to use a neural interface instead of normal controls.  Such a setup requires some means of interface (such as a neural interface implant in the pilot), but reduces the cost of the needed seating to only $100.
Optionally, a character controlling a mecha with Battlesuit skill suffers a penalty equal to the difference in SM between the character and the mecha, which can be negated with a per-SM Perk.  Without the Perk, simply raising Complexity of the controlling program back to C3 will negate the penalty.

Hydraulics:  A mecha that is controlled using a supported bodysuit can be designed to integrate that character’s strength, allowing him to contribute to BL.  The additional musculature that allows this is at 1/10th normal weight.  Note this usually isn’t worthwhile unless the character is abnormally strong or the mecha is particularly weak.


Example:  Let’s say we want to design a battlesuit at TL10 that will give an ST 10 character a net Striking ST 15, Lifting ST 20.  That means general BL is going from 20 to 45, while Lifting BL is going from 20 to 80.  The +25 lb BL general suit has (0.5/10)*25^(3/2)=6.25 lb of TL10 synthetic muscle and (0.5/40)*25^(3/2)=1.56 lb of advanced polymer nanocomposite scaffolding.  A +60 lb BL general suit would instead have 23.24 lb of TL10 synthetic muscle and 5.81 lb of advanced polymer nanocomposite scaffolding.  That would be +16.99 lb muscle and +4.25 lb scaffolding, but as this is Lifting BL only, the additional muscle weight is halved to 8.5 lb, and the additional scaffolding weight is reduced to 30%, or 1.275 lb.  Total weight is therefore 14.75 lb TL10 synthetic muscle ($22125) and 2.835 lb advanced polymer nanocomposite scaffolding ($708.75).  With a 150 lb pilot, that’s a total of 167.59 lb, leaving us with up to 432.41 lb of additional payload before we need to even worry about encumbrance.

A standard 20 lb E-cell will power such a battlesuit for (150/(0.5*42.5))=7.06 hours.  If we instead wanted a dedicated power plant, it would need an output of (5*42.5)=212.5 W.  We’ll want to include some sort of computer - we’ll go with a Hardened Tiny Computer (C5, 2A/20 hr, $100, 0.1 lb).  For armor, typical threats are going to be piercing (bullets) or burning (lasers), so we’ll cover it in bioplas.  That’s MaxDR 138/46 for the Skull/Chest, 92/30 for everywhere else.  We’ll go with an optimized fabric bioplas suit of 135/90 (45/30 against everything but pi/burn), which is 10.773 lb for the Skull/Chest, 15.876 lb for everywhere else, and thus 26.65 lb total.  Cost would be $31980, but we’ll have 1/6 protection on the Face be transparent (so the wearer isn’t blind), which boosts cost by $75.60, to $32055.60.

As for accessories, we’ll want Sealed ($106.75), a waste relief system ($500, 1 lb), biomedical sensors ($100), a personal radar/ladar detector ($50, 0.5 lb), trauma maintenance ($2000), a large air tank ($200, 10 lb), an extended life support system ($2000, 1 lb, 1C/18 hours), a tiny radio ($50, 0.05 lb), a filter ($100), a provisions dispenser ($50, 1 lb), hearing protection ($50), and a hyperspectral HUD ($2000, 0.6 lb).  None of the accessories burn through energy quickly enough to make a real impact on endurance, so it will stay at 7 hours per E cell.

All told, after rounding to 2 significant figures, we’re looking at $62,000 and 59 lb.  Counting our 150 lb wearer, that’s a total weight of 208 lb out of an expected 600 lb.  Assuming less than 92 lb of gear (including the power cell and any backups), the character will have Movex2 while within the suit, and +5 to DX-based Battlesuit skill.  His chest and skull have DR 135 against pi/burn (protecting from a point defense laser, anti material rifles firing APHC, or sniper railguns) and DR 45 against everything else (protecting from a gatling pulse laser).  Everywhere else is DR 45 against pi/burn (protecting from a laser rifle, assault carbine firing APHC, or a gauss PDW) and DR 15 against everything else (protecting from a survival pulse laser).

Thursday, March 2, 2017

Combat Posture, Simplified

During discussion on the GURPS forums, I realized there's a way to make things a bit simpler.

Integration

Starting MP:  Characters start with 20 MP.  Optionally, characters can start with more MP, at [10] per +1.  Less MP might also be an option, similarly at [-10] per -1.  Limits are up to the GM; +10 is suggested.

Bonus MP:  Characters with high skills and defenses can gain additional MP by opting not to use them.  A character who chooses not to invest any MP in Attack or Aim gains 1 Bonus MP for every 2 points their best melee or ranged skill is above 14.  Such Bonus MP can be invested in Defense, Awareness, Evaluate, or Ready.

A character who instead chooses not to invest any MP in Defense gains 2 Bonus MP for every point his Dodge is above 9.  He also gains 1 Bonus MP for every point his best defense is above Dodge or 9, whichever is higher.  Such Bonus MP can be invested in anything but Defense, Awareness, or Evaluate.

Optionally, if the character has higher Melee skill than Ranged, his Bonus MP is based on Ranged skill, and he also has Melee MP equal to the difference.  Melee MP only boosts Defense against melee attacks, Awareness only gives a bonus within Per yards, Evaluate works normally, and Ready only works melee weapons.  If the character has higher Ranged skill than melee, his Bonus MP is based on Ranged skill, and he also has Ranged MP equal to the difference.  Ranged MP only boosts Defense against ranged attacks, Awareness works normally, Evaluate doesn't work at all, and Ready only applies to ranged weapons (and reloading them).

Similarly, it may be appropriate to not allow Bonus MP from Parry or Block to improve Attack, Damage, or Aim for ranged attacks

Trading FP for MP:  A character can exchange FP for MP at any point, at a rate of 4 MP per FP.  This replaces the normal rules for Extra Effort in Combat.  If using The Last Gasp, you may instead exchange AP for MP.

Acrobatics MP:  Once per turn, at any point, a character may attempt to use Acrobatics or similar to gain additional MP.  On a Success, the character gains 2x(MoS), minimum 1, MP.  On a Failure, the character loses 2x(MoF) MP.  Gained MP can be spent to negate Attack penalties for Acrobatic Attack, to enhance defense (in the manner of Acrobatic Dodge), or for Movement.  Lost MP from a Failure can be reclaimed by lowering the character's Posture - going from standing/crouching to sitting/kneeling or sitting/kneeling to prone/supine recovers 4 MP, while going form standing/crouching to prone/supine recovers 8 MP.  If a character has already allocated his MP for the round when making this attempt (such as for an Acrobatic Dodge), lost MP is taken from Defense.  If falling prone/supine and losing the ability to defend is insufficient to offset the MP loss, the character suffers a pratfall and must roll against HT+5 - Success means he is Stunned, Failure means he is rendered unconscious.  An already Stunned character doesn't get a roll here, and is simply rendered unconscious.

Stunning:  A character who is Stunned is at 1/4 MP (base 5).  Bonus MP from Acrobatics or forgoing attacks/defenses (see later) are similarly reduced, but those from spending FP/AP are not.  He can still spend MP normally, however.  This allows him to attempt weak attacks, clumsy defenses, or stumble away at reduced Move.


MP may be spent as follows.

Attack:  Making an attack costs 6 MP, which allows an attack at -4 to skill.  Each additional MP gives a +1 to attack, to a maximum of +4 for melee attacks; ranged attacks are limited to a maximum of +2.  Optionally, every 2 points above skill 14 increases this cap by +1 for melee attacks; ranged attacks are instead +1 per 4 points above skill 14.  MP can also be spent to reduce or negate penalties other than those resulting from Range or use of Deceptive Attack, Setup Attack, Predictive Shot, or similar - every 2 MP negates up to -3 in penalties.  Penalties for hit locations and similar are still limited to 1/2 the initial penalty being negated, however.  For melee attacks, you may add one - and only one - extra yard of Reach to your attack for 4 MP (optionally, use "A Matter of Inches," with each step above Average being -1 MP to cost, each step below Average being +1 MP to cost).  For a ranged attack to benefit from a previous Aim, you must spend an additional 2 MP.

Note the above is a one-time cost - to get additional attacks, use Dual Weapon Attack, Rapid Strike, etc, at the normal penalties.  MP invested to reduce penalties can eliminate these as well.

Damage:  If making an attack, damage can be improved.  Every 2 MP is +1 or +0.5/die to damage, whichever is better.  This cannot exceed +4 (8 MP) for an attack dealing 1d+n damage, or +3.5 (14 MP) for an attack dealing 2d+n damage or more.  Additionally, melee impaling weapons that strike a target can be purposefully wrenched out to cause additional damage.  This costs at least 1 MP and calls for an attack roll, at -4 relative to the first.  This can be defended against normally, with a successful defense meaning the weapon is pulled out without further injury, but the defense suffers the full Shock penalty of the initial injury.  Swing impaling weapons are harder to do this with, due to poor leverage, calling for an additional -3 to skill (total -7).  Barbed weapons are also harder to remove, suffering the same -3.  Every MP results in 20% of the initial injury being suffered as the weapon is pulled out, to a maximum of 60% for 3 MP.  For barbed weapons, this is instead 30% per MP, to a maximum of 90% for 3 MP.  For swing impaling and barbed weapons, dealing 60% or more injury prevents them from being stuck in the target.

The character can reduce the MP cost for attacking by dealing less damage.  This is 5 MP for -1/die, 4 MP for -2/die, and 3 MP for causing no damage.  A no damage attack can be a tap (for delivering touch effects) or a Feint or similar.  For characters making multiple attacks, this damage reduction must apply to all of them to get the discount.

Defense:   Being able to defend costs 6 MP, which allows defenses at -2.  8 MP increases this to -1, and 10 MP allows full defense.  Following this, you may improve defenses, at a rate of 2 MP per +1 to a single use of a defense, 4 MP per +1 to all uses of a given defense, or 8 MP per +1 to all defenses.  You may also spend 4 MP for a single use of a Double Defense, or 8 MP to make all defenses for the round Double Defenses (a Double Defense is where you get to roll two different defenses against a single attack).

A character who starts with less than 5 MP, due to Stun or similar, can opt to spend all MP on defense, allowing defenses at -4.

Movement:  You get a free Step or Retreat.  Each additional Step costs 2 MP, to a maximum of half Move (the GM may extend this to full move for chambara and similar games).  Simply moving up to half Move costs 6 MP, while moving up to full Move costs 10 MP.  If making an attack with a ranged weapon, half Move results in an attack penalty equal to half Bulk, while full Move results in an attack penalty equal to Bulk.  Changing Posture costs 10 MP to go a single step (prone->kneeling, kneeling-crouching/standing), 20 MP to go two steps (prone->crouching/standing).

Awareness:  If using Situational Awareness from Tactical Shooting, the default is -4 to the roll for 0 MP (a glance).  Every 2 MP is worth +1 to this, to a maximum of +8 or (skill/2+1), whichever is better.  "Skill" here is the best of Perception, Observation, Per-based Soldier, and Per-based Tactics.

Recovery:  If using The Last Gasp, it costs 2 MP to attempt to recover AP.  This allows for an HT-4 roll.  Each additional MP is a +1 to this roll.

Aim:  If using Take Aim, resolve this as an attack (but with no option to increase or reduce Damage).  If not, Aim costs 10 MP.

Concentrate:  For actions that require a roll, treat this much like Attack, above.  For actions that require multiple rounds of Concentrate, followed by a roll, you must spend at least 6 MP each round on Concentrate, and roll based on the average MP spent (it's easiest to just maintain the same cost each round, however).  For actions that don't require a roll, Concentrate costs 10 MP.

Evaluate:  Every 3 MP spent on Evaluate negates -1 in penalties from Feints, Deceptive Attacks, etc from the target in question over the round, and also give you an additional 1 MP to spend only against that target next round.  Such Evaluate MP are limited to the greatest of Melee MP, Ranged MP, and Dodge MP.

Ready:  As Concentrate, above.  If Fast-Draw reduces this to a free action, it costs 0 MP.

Wait:  A character can opt to delay his turn with a specific trigger, as usual.  Optionally, he must dictate his Combat Posture (where he is spending his MP) upon declaring the Wait.


Redistributing MP:  A character can reclaim "overspent" MP and spend it elsewhere (typically on either Defense or Evaluate, but Awareness may also be an option).  If the character was prevented from using some amount of MP, he can reclaim up to half of it.  If he did use it, but had a higher MoS than needed, he can reclaim up to a third of the excess.  Note this latter option essentially retroactively drops your effective skill, so you may not want to do it if you expect to make further rolls against that skill, and you can only reclaim points based on your lowest such roll during the round.



Let's rerun our example character through the paces.  Once again, he's a rifle-toting TL 5 mage named Jack, with ST 13, HT 12, Dodge 11 and Move 7.  His best melee skill is Spear 16 (for bayonet fighting), his best ranged skill is Guns(Longarm) 18, he has Acrobatics 14, Path of Energy 20, and Fast Draw (Ammo) 18.  His best Awareness skill is Per-based Soldier, at 14.  He also has Bayoneteer (no Guns penalty for having an attached bayonet), Combat Reflexes, Ritual Adept, Ritual Mastery (MTC Shot), and Quick Reload (Muzzleloading Rifle).  He could also have a Hold Spell Perk (letting him finish gathering energy for a ritual, then wait to actually cast it, rather than doing so immediately), but I think that functionality is balanced enough to be the RPM default.

He starts with 20 MP, as normal.  If he opts not to attack, he has Bonus MP 1, Ranged MP 1.  If he chooses not to defend, he has Bonus MP 2, Melee MP 1.

At base, Jack can attack with his bayonet at skill 12 or his rifle at skill 14 for 6 MP, Dodge at 9 and Parry at 10 for 6 MP, or move up to 4 yards for 6 MP.  If not spending anything on Awareness, he rolls against 12 there.  He can attempt to recover AP with a roll against 8 (HT-4) for 2 MP.  He can boost Spear up to Skill+5, or Guns(Longarm) up to Skill+6.  He's at Dodge 10 Parry 11 for 8 MP, Dodge 11 Parry 12 for 10 MP, after which he uses the normal (2 MP per single +1, 4 MP per outright +1 to single defense type, 8 MP per +1 to all defenses).

Let's say Jack is in a long battle, and has exhausted his supply of MTC Shot Charms (MTC Shot is a 30 energy ritual that enhances the burn of gunpowder, markedly increasing damage).  He gets behind some cover and starts loading a normal bullet while gathering energy for MTC Shot.  Reloading with Fast Draw is going to take him 12 seconds.  As he's not going to Attack, he gets 1 Bonus MP and one Ranged MP, in addition to his base 20 MP.  He spends 6 on Concentrate, 8 (6 base, 1 bonus, 1 ranged) on Ready, and 8 on defense.  He continues this for 5 rounds without issues, calling for a roll against MTC Shot.  With only 6 MP invested in it, he's rolling against an 18.  He gets a 10, gathering 8 energy.

He continues on, but when he rolls an 8 against his Awareness 12, he notices a sorcery-twisted, misshapen husk of a man charging him with an oversized sword.  Rather than fight with his back to the wall, he temporarily stops reloading, continues spending 6 MP on his ritual, spends 2 MP for an extra Step, spends 9 (7+2) on Defense, and the remaining 7 on an attack, charging and thrusting at the creature at skill 13.  He scores a hit, but it bats his weapon aside and steps in with a swing.  He burns 1 FP, spending 2 MP on getting a +1 to this Dodge, and 2 MP on getting an extra Step, which he uses to Retreat, for an effective Dodge 14, letting him get out of the creature's way.  Some bullets are hitting the ground near him, so he knows he needs to end this quickly and get back to cover before his foes decide to aim first, so he eschews defense this next round, gaining Bonus MP 1 and Melee MP 1.  He spends 6 MP on Concentrate, 10 MP (8+2) on his attack, 2 to increase damage, 2 to rip the bayonet out for still more damage (assuming a hit), and 2 to negate -3 of the penalty to stab the thing in its exposed neck.  That's an attack at 16 (seriously screwed up my math in the previous example), with a success dealing 1d+4 (2d) damage and allowing for an attack at 12, with success dealing a further 40% of initial damage.  He opts for a -4/-2 Deceptive Attack, for skill 12, and he rolls a 7 on his attack  The target fails its defense, and he rolls for damage - 10.  This becomes 20 injury, and he rolls against 12 (opts against going deceptive), rolling an 11.  Thanks to the -4 from shock, the creature fails its defense against this, and suffers a further 8 injury.  It fails its Death Check markedly, and the GM rules Jack very nearly decapitated it ripping his blade out.  Jack uses the free step remaining in his maneuver to get back into cover.

The rest of his time reloading and gathering energy is uneventful - on second 10 he rolls a 9, gathering 9 energy.  On second 14 (he lost 2 seconds killing his attacker) he finishes reloading - as each second he spend actually reloading was with 8 MP, he rolls against 16 to reload, and succeeds - his rifle is ready for shooting.  Without reloading eating up his concentration, he puts the 12 MP into Concentrate, 10 (8+2) into Defense, for Dodge 11 against ranged attacks (Dodge 10, Parry 11 against melee).  He gets another roll against Path of Energy, which spent 4 seconds of the last 5 with skill 18, 1 second with skill 24, for an average of skill 19, which gets reduced to 18 for being the third gathering attempt - a 12 means 6 more energy (running total is 23).  Figuring he'll have the spell ready soon, he changes things up again - 8 in Concentrate, for skill 20, 10 (8+2) in Defense, for 11 Dodge/Parry, and 4 in Awareness, boosting that to 14, so he can try to find someone worth shooting.  By the end of those 5 seconds, he's located an enemy mage protected by more of those misshapen men, and is ready to roll to gather again.  Effective skill is 19 (again, -1 for beyond beyond the 3rd gathering attempt), and he rolls a 10 - enough to complete the ritual.

With the ritual ready to go, he takes aim at his target.  He spends 10 on Defense and 10 on Aim, letting him do so at full skill (minus half range).  He succeeds, and rolls well enough that he gets his full Acc (4) against the target.  He's in a decent defensive position, and he has his eyes on a high-value target, so he eschews defenses for the follow up attack (for +2 MP).  He needs one last Concentrate to finish his ritual, and also needs an Attack to actually fire the weapon.  6 MP is the minimum he can spend for the Concentrate, putting him at skill 18.  He spends 16 (14+2) MP total on Attack - 12 to attack at Skill+2, 2 to negate -2 for targeting the Vitals (leaving -1 left) and 2 to benefit from Acc (+4).  Against a target 20 yards away (-10), that's an effective skill of 13.  He rolls a 15 on the spell, successfully casting it, and an 11 on the attack.  The enemy mage - who failed to notice Jack taking aim at him - is struck by that magically-enhanced bullet and collapses to the ground.

Tuesday, February 28, 2017

Combat Posture

For our first Overhaul on this blog, we'll be getting rid of the distinctions amongst maneuvers.  The original plan was to combine Extra Effort in Combat, All Out Defense, Defensive Attack, Committed Attack, and All Out Attack, using the Technique Design System from Martial Arts, into one cohesive whole, but things ended up going a bit further than that.  This is largely inspired by this post of mine on the GURPS forum, and is arguably only an option for cinematic campaigns.  In addition to unifying these to get a smoother progression, this is also meant to give high skill characters a reason to use (the equivalent of) All Out and Committed Attacks.

Those who would prefer to look at the system without reading everything that went into it will be well served by skipping down to Integration.

First off, we need to define what modifiers are available.  Note all cases of +n to damage can also be interpreted as +(n/2) per die to damage.

Extra Effort lets you trade in 1 FP for one of +2 on a defense, +2 damage on an attack, full Move instead of a Step, 1 extra hex of Reach, or +3 to hit, but only to negate the penalty for a Rapid Strike.

All Out Defense means forgoing an attack this round but gives +2 to Parry or Block, +2 to Dodge and half move, or lets you use two defenses against a single attack (Dodge and Block, say).

Defensive Attack means you suffer a -2 to damage but gives you +1 to Block or Parry (or +2 to avoid a Leg Grapple or a fall, when kicking) or lets you Parry with an Unbalanced weapon.

Committed Attack means you suffer a -2 to defense, the loss of the defense associated with the attacking weapon (Parry for a weapon strike or punch, Block with a shield bash, Dodge with a kick), and the loss of the ability to Parry, in exchange for a +1 to damage or +2 to hit.  It also gives the option of taking a -2 to hit to get an extra Step.

All Out Attack means you lose the ability to defend outright.  In exchange, you can move up to half Move and get a +4 to hit, +2 to damage, attack twice at no penalty, or an extra hex of Reach.

For Extra Effort, as Techniques, those are worth -4 to hit, -4 to hit, -5 to hit, -4 to hit, and -3 to hit, respectively.  For Great Lunge, the effect is the same as taking a Step forward, attacking, and taking a Step back, for 2 extra Steps (because it still allows you to take your normal one) which are worth -4.  The fact you can't take the Steps is balanced out by the fact that you don't Step - you can use this to strike a foe on the other side of a chasm.  Overall, this works out to about a +4 to hit for 1 FP.  Technically, that first one, as a Technique, would give you +2 on every use of that particular defense (say, Parry), while Feverish Defenses only gives you a +2 on one.  This is worth further consideration, but let's keep going.

For All Out Defense, +2 Parry, Block, or Dodge is worth -4 to hit.  Half move is arguably worth -3 - it's worth more than the -2 of Extra Step, but not as much as the -5 of getting full Move.  -3 seems about right - half the penalty (round against the character, as is GURPS standard) for half the movement.  By probability, getting two defenses is roughly equivalent to getting one at +2, so it's also worth -4 to hit.  All Out Defense is thus worth +4 to hit for most uses, or +7 for Improved Dodge.

For Defensive Attack, that -2 to damage is worth +4, while the +1 to Block or Parry is only worth -2.  Parrying with an Unbalanced Weapon isn't defined, but I'd be tempted to call it a -2 to hit.  Kind of a raw deal - you're only getting a benefit from half of your damage penalty.

For Committed Attack, -2 to defense is worth +4 to hit.  Loss of one defense and ability to Retreat is arguably worth +1.  This is also a raw deal, as for +5 worth of penalties you can only get +2 to hit or +1 to damage (which is worth the same as +2 to hit).

For All Out Attack, half move is worth -3 (as noted above), and each Dedicated, Strong, and Long are worth -4.  Double is with -4 if you use different weapons for each attack, -6 if you use the same.  Overall, All Out Attack is worth around +7 to hit.


So, where do we go with this wall of text?  First off, let's revisit those defense bonuses.  We're rather consistently seeing them being traded in for less than they are worth - -4 for +2 to a single use (instead of -4 for +2 to all uses for the round) with Extra Effort, Improved Parry, Improved Block, and Double Defense are each worth roughly half what All Out Attack is worth, despite the fact the two All Out options should be equivalent, and similarly we see -4 traded for a +1 to Block or Parry with Defensive Attack.  The solution here actually seems easy enough to me - we assume the Technique Design System is wrong about what defense bonuses are worth.  Instead of -2 to hit being worth +1 to a defense for that round, -2 to hit is worth a +1 to a [i]single[/i] defense that round.  Note this maintains parity with the rules for penalizing a foe's defenses - you only penalize the foe's defense against that one attack, not all of his defenses for the round.  Getting a +1 to all uses of that defense for the round is worth -4.

That fixes Feverish Defenses, most of All Out Defense, and Defensive Attack with balanced weapons.  Note this means All Out Defense is actually worth +8, rather than the +7 of All Out Attack.  It may be appropriate to have an unlimited boosted defense actually be -3.5 per +1, for a progression of -4, -7, -11, -14, etc.  For Improved Dodge, well, I've never been that fond of it giving you half Move there anyway, so we'll just outright drop that (but note you can add it back in once we're done).  For Defensive Attack with Unbalanced weapons, an easy out would be to say that retaining defenses with a Parry U weapon is actually worth -4, not -2.  If you feel -2 is a more appropriate price, however, then you'll end up with +2 left over.

As mentioned in the linked thread, the +7 for All Out Attack could be standardized to a character with Parry 10 and Dodge 9.  The character gets a +4 to attack by suffering a -2 to all defenses, gets a +1 for suffering a further -1 to all defenses better than Dodge (dropping everything to 7, the lowest you can go before risk of Critical Failure goes up), and finally gets a +2 for outright giving up the ability to defend, itself broken into +1 for giving the defense related to the attack and losing the ability to Retreat, and +1 for expanding this to giving up all defenses.  A character with higher defenses can get a better rate - drop defenses as above until everything is at 7, then apply a further +2 for giving up all defenses.  For example, a character with Dodge 10 and Parry 14 would get a +6 for dropping to Dodge 7 and Parry 11, +4 for dropping Parry down to 7, and +2 for giving up all defenses, for a total of +12.  Ignore DB for these calculations - while using a Balanced sword with which you have a Weapon Bond gets you a better rate, lugging around a shield doesn't.  For characters with defenses too low for a +7, simply give them a +7 for giving up defenses.

All Out Defense follows something of a similar trend.  Work out the bonus the character would get for giving up defenses.  This is what opting to give up attacks is worth, and is made in a staggered fashion - for a character who gets a +7, it's simply a damage penalty, -0.5 per die (-1 with 1d) per +1 to hit (-3.5 per die means no damage - or no attack - for +7).  For those with higher defenses, subtract 7 from the bonus you'd get with All Out Attack.  These additional points may be traded in equally following the -1 per die, -2 per die, and -3 per die, for -1 to hit, favoring penalties sooner rather than later.  For our Dodge 10, Parry 14 character from above, he has +5 left over.  His progression for boosting his defenses is -1 per die for +2, -2 to hit for +2, -1 per die for +2, -2 to hit for +2, -1 per die for +2, -1 to hit for +1, and finally -0.5 per die, reducing damage to zero, for +1, for his total of +12.


With all that out of the way, here's how I see things working out.  First off, All Out Defense, Defensive Attack, Committed Attack, and All Out Attack are no longer their own maneuvers.  Rather, each time the character chooses a maneuver, he may set his Combat Posture (better names welcome - this overlaps a bit too much with actual Posture; Combat Stance might be better, although that might overlap too much with the options from Gladiators).  Combat Posture dictates what resources you are attributing to Attack, Damage, Defense, and Movement.  Instead of the +n notation from above, let's make these their own points - PP (Posture Points) or AP (Action Points) would be ideal, but those abbreviations are already taken.  I'm tempted to go with MP, for Maneuver Points (as you're dictating the nature of your maneuver for the round).  You normally have 0 MP.

Attack:  Every +1 to hit costs 1 MP, to a limit of +(skill/2-3), minimum +4.  Every +3 for purposes of negating penalties other than those for using Deceptive Attack costs 2 MP.  You may add one - and only one - extra yard of Reach to your attack for 4 MP.

Every -1 to hit gives you 1 MP, to a limit of -(skill2-3), minimum -4.  Opting not to attack at all is worth a further 3 MP.

Damage:  Every +1 to damage costs 2 MP, to a maximum of +4 to damage for 8 MP.  For characters who deal 2d-1 or greater damage, this is instead +0.5 per die to damage for 2 MP, to a maximum of +3.5 per die (double damage) for 14 MP.  A character who injures a foe using an impaling attack may spend MP to tear the weapon out, increasing injury.  This is a free attack, at -4 to skill, and costs 1 MP per +10% injury, to a maximum of +50%.  For barbed weapons, this is instead +15% per MP, to a maximum of +75%.  For swing impaling and barbed weapons, there's a further -3 penalty due to poor leverage, but dealing +50% injury automatically dislodges the weapon, leaving it ready for further action.

-1 per die to damage is worth 1 MP.  -2 per die to damage is worth 2 MP.  Dealing no damage is worth 3 MP.  Note you must actually be able to make an attack in order to claim MP for taking a damage penalty.  If not using Technical Grappling, grapples cannot opt for reduced damage.

Defense:  Every +1 to a single use of a defense costs 2 MP.  Every +1 to all uses of a single defense during the coming round costs 3.5 MP (round final cost up).  Every +1 to all defenses costs 7 MP.  Using two different defenses against a single attack costs 4 MP.  Using two different defenses against each attack during the coming round costs 7 MP.

Every -1 to all defenses is worth 2 MP, to a minimum of Dodge 7.  If you have any defenses that are better than Dodge, every -1 to all defenses but Dodge is worth 1 MP, to a minimum of Dodge.  Giving up the defense associated with the action you have taken this round (Parry for a sword strike, Dodge for a kick) and the ability to Retreat is worth 1 MP.  Outright giving up all defenses gives 2 MP above the worth of reducing all defenses to 7 or lower, to a minimum of 7 MP.

Movement:  Each Step beyond the first costs 2 MP, including Retreats; distance traveling this manner cannot exceed half Move.  Normal movement up to half Move costs 3 MP.  Normal movement up to full Move costs 7 MP.  Sprinting, using Enhanced Move, or similar costs 10 MP.  Changing posture by 1 step costs 7 MP, while doing so by 2 steps costs 14 MP.

Giving up the ability to Step and Retreat is worth 2 MP.  Note you may not combine this with the Retreat-limiting Defense option, above.

Other Actions:  If we're getting rid of maneuvers, we need the handle things like Concentrate, Evaluate, Ready, and Wait.  Actions that call for Concentrate or Ready cost 7 MP - most characters will forgo an attack to use such.  If they call for a roll (and I'm personally inclined to have Ready for weapons call for a roll against weapon skill), you may reduce the MP cost by penalizing the roll.  This is typically -1 to the roll per -1 to MP cost, to a limit of -(skill/2-3), minimum -4, maximum -7.  You may also be able to gain a bonus for spending extra MP, for +1 to the roll per +1 to MP cost, to a limit of +(skill/2-3), minimum +4.  Some cases are different - for example, the Per/Observation roll for "Situational Awareness" (TS11) is at only -4 for a free action (0 MP), implying -2 MP per -1 to skill, to a maximum of -7 MP for -4 to skill.  It may be appropriate to use the same trend for bonuses in this case - 2 MP cost per +1 to the roll, to a limit of +(skill/2+3), minimum +4.

Evaluate we'll handle in a bit (see Unspent MP, below).  With Wait, you're basically just delaying your action in the turn sequence, so nothing special is needed here.  Optionally, you could require the character to set his Combat Posture upon declaring a Wait - note this will prevent the character from being able to switch between Attack and All Out Attack (or, rather, their equivalents) based on what happens between declaring and activating the Wait.

Negative MP:  A character cannot take any action that will drop him below 0 MP.

Getting Extra MP:  At any time, a character may exchange FP for MP, at a rate of 1 FP becoming 4 MP.  If using The Last Gasp, you may instead exchange AP for MP, at a rate of 2 AP becoming 1 MP.  Additionally, Acrobatics or similar skills may be used once per round, at any point, in an attempt to gain an MP boost.  Success gives MP equal to Margin of Success (minimum 1 MP), Failure costs MP equal to twice Margin of Failure.  If you don't have MP to spare, you must make up for it by spending FP/AP or taking defense penalties.  The GM may also allow you to suffer a fall, regaining 4 MP if you go from standing/crouching to sitting or kneeling/sitting to prone/supine, or 7 MP if you go from standing to prone/supine.  Gained MP must be spent in a manner appropriate for the skill - for acrobatics, this might be reducing the penalty for a Acrobatic Attack, spending MP on an acrobatic stand, increasing Dodge, or similar.

Unspent MP:  If you still have MP left at the start of your next turn, divide it by 3, dropping fractions.  Each such MP must be assigned to a particular foe (typically all will be to the same foe, but splitting MP between foes is an option), and can only be used for Attack, Damage, or Defense against that particular foe.  If those MP remain at the start of the following turn, they are lost, unless you assign more leftover MP this round; each additional MP stabilizes one other (so if you had a foe that you had 4 MP assigned to last round and you assign another 3 this round, 1 MP is lost and you have 6 MP assigned to him).  This replaces the Evaluate maneuver.

AP Recovery:  If using The Last Gasp, a character may spend MP to attempt to recover AP.  Spending 1 MP allows an HT-8 roll.  Each additional MP is a +2 to this roll.  A typical character who eschews offense, defense, and movement in order to rest has 16 MP to spare (7 for not attacking, 7 for not defending, 2 for no movement), which is sufficient for an HT+18 roll!  The roll - and subsequent AP gain - occurs at the start of the character's next turn.

Stunning Fun:  Optionally, a character who is Stunned may, instead of the normal effects (cannot move, cannot attack, -4 to all defenses), be treated as having -20 MP, needing to take appropriate penalties to bring this up to at least 0.  The character always has the option of simply being treated normally for Stun.

Adjusting Combat Posture:  A character can change his Combat Posture between turns, so long as doing so wouldn't have had a negative effect on his previous actions.  The exchange rate is poor, however - every MP is worth half its normal effect.  For example, a character who intended to attack but wasn't able to (say, his movement activated a Wait that prevented him from reaching a target) could claim the 7 MP he would have had he opted to not attack at all, repurposing them to defense or similar.  Additionally, when the character succeeds at an action, before final resolution he may opt to reduce his MoS - every -3 to MoS is equivalent to taking a -1 to the roll.  For example, a character who succeeds at an attack with MoS 9 could drop this to MoS 0 and regain 3 MP (provided he could have taken a -3 to the attack).

Spending MP between turns uses the normal rate, but can typically only be used for improving defenses (either directly or by taking a Retreat).  MP gained by sacrificing FP or AP also uses the normal rate.


What About Range?
All of the above looks at things in terms of melee, but how should ranged combat work with Combat Posture?  First off, the Combat Posture system should be used in conjunction with Take Aim.  That has Aim basically following the same trend as attacking, above, so we can just replace one with the other without serious issue.  Even if not using that system, making Aim the equivalent of an unrolled Ready or Concentrate would be fine.

For All Out Attack, first off that's basically indistinguishable from the melee version at extreme close range, so we're good there.  At longer range, what do we get out of it?  A +2 to hit (+1 normally, but I'm using Take Aim here), half Move, and (if using Tactical Shooting) the ability to benefit from an Aim.  Now, we should note here that Move and Attack is different with ranged weapons than with melee - the penalty is equal to the weapon's Bulk, minimum -2.  Instead of our -3 (3 MP) from above, that implies half Move would suffer half Bulk, minimum -1.  A "typical" ranged weapon is probably Bulk -4 or Bulk -5 (carbines and assault rifles), although this varies with TL (most bows and crossbows hover around Bulk -6, most carbine/rifle-type beam weapons hover around Bulk -3 or Bulk -4).  Regardless, the 3 MP charge for movement would be enough to negate up to Bulk -8, so we're good there (yes, we're letting the same MP spent for movement serve to negate the penalty for movement here, but that's kind of how Move and Attack works above anyway).  The next 2 MP are only getting us a +2 to hit, implying that being able to benefit from Aim is worth 2 MP.  Alternatively, if you don't want to have any sort of extra charge to benefit from Aim, simply halve the bonus you get from investing MP in the attack.

All that in mind, here's how things look for ranged attacks.

Attack:  Every +1 to hit costs 1 MP, to a limit of +(skill/4-1.5), minimum +2.  Within melee range, simply use the same progression as melee.  Every +3 for purposes of negating penalties other than those for using Prediction Shot costs 2 MP.  If attacking after a successful Aim, benefitting from this costs 2 MP.  Note attacks in melee range may suffer Bulk penalties (which you can buy off, as above) and do not have the option of benefitting from Aim.

Every -1 to hit gives you 1 MP, to a limit of -(skill/2-3), minimum -4.  Opting not to attack at all is worth a further 3 MP.

Damage:   This follows the same progression as melee.  However, those rules only apply with thrown weapons and similar (such as those launched with slings), unless playing a highly cinematic game (where dealing extra damage from a gunshot is fluffed as striking a vulnerable sublocation).

Defense:  This follows the same progression as melee.

Movement:  This follows the same progression as melee.  However, if both moving and attacking, add 8 to the weapon's Bulk score, treating any result greater than 0 as 0.  If moving half Move, apply half the remainder as a penalty to the character's attack.  If moving full Move, apply the full remainder as a penalty to the character's attack.


Wait, Let Me Grab my Sword First
An oddity of the system is that, at high skill levels, a character using his favored weapon is better at dodging, noticing threats, or even casting spells.  Similarly, a character with a high enough defenses gets a larger bonus for out-of-combat actions than other characters.  To avoid this, it is appropriate to limit what MP can be spent on, based on where it came from.  It's also more appropriate to set the points a character gets for, say, not making an attack to his highest combat skill, such that a skilled swordsman doesn't have worse situational awareness when he doesn't have a sword in hand.

What MP from a given source can be spent on is up to the GM, but here are some ideas.  First off, any combat skill or defense is legitimate to use MP gained from penalties to it to enhance Situational Awareness.  Also,   For melee combat skills, penalties to Attack or Damage can be used to enhance any defense, but enhancing Dodge against ranged attacks is only half as effective.  For ranged attacks, penalties to Attack or Damage can be used to enhance Dodge against ranged attacks, but enhancing any other defense (including Dodge against melee) is only half as effective.  In either case, they can pay for Movement freely (a more skilled combatant can move a bit more freely).  For MP gained from reducing Defense, those gained from only reducing defenses higher than Dodge can be used for Attack or Damage with melee attacks only, or for Movement.  Those for reducing all defenses can be spent freely for Attack, Damage, or Movement.  Note such limitations only apply to those gained beyond the minimum 7 for each category.


Integration

All of the above has Combat Posture feel more like something added in, rather than something that's an innate part of things.  Instead of having characters reshuffle MP, what if we had them start each round with a set amount, and have them spend them on what Combat Posture they'd prefer?  Here's how I see it working out.  Note some numbers have been shifted slightly from the above, simply to make things work out a bit more easily.

Starting MP:  Characters start with 20 MP.  High Dodge increases this - add MP equal to 2x(Dodge-9), minimum 0.  High combat skills and defenses can give an additional bonus, but this MP is only usable for certain uses.  Melee MP and Ranged MP are linked - spending one automatically spends the other for the same purpose (but these do not stack), even if such a use isn't available.

Melee MP:  The character has Melee MP equal to the sum of (Skill/2-7), minimum 0, based on his highest melee skill, and the lower of (Defense-9) and (Defense-Dodge), minimum 0, based on his highest Block or Parry, ignoring modifiers for gear, DB, etc.  Such MP can be spent on Attack, Damage, and Defenses, but only for (and against) melee attacks.  It may also be spent on Readies for weapons of the appropriate skill.  It can also be used for Movement and Awareness.

Ranged MP:  The character has Ranged MP equal to (Skill/2-7), based on his highest ranged skill.  Such MP can be spent on Attack, Damage, and Defenses, but only for (and against) ranged attacks.  It may also be spent on Readies for weapons of the appropriate skill.  It can also be used for Movement and Awareness.

Acrobatics MP:  Once per turn, at any point, a character may attempt to use Acrobatics or similar to gain additional MP.  On a Success, the character gains 2x(MoS), minimum 1, MP.  On a Failure, the character loses 2x(MoF) MP.  Gained MP can be spent to negate Attack penalties for Acrobatic Attack, to enhance defense (in the manner of Acrobatic Dodge), or for Movement.  Lost MP from a Failure can be reclaimed by lowering the character's Posture - going from standing/crouching to sitting/kneeling or sitting/kneeling to prone/supine recovers 4 MP, while going form standing/crouching to prone/supine recovers 8 MP.  If a character has already allocated his MP for the round when making this attempt (such as for an Acrobatic Dodge), lost MP is taken from Defense.  If falling prone/supine and losing the ability to defend is insufficient to offset the MP loss, the character suffers a pratfall and must roll against HT+5 - Success means he is Stunned, Failure means he is rendered unconscious.  An already Stunned character (see later) doesn't get a roll here, and is simply rendered unconscious.

Trading FP for MP:  A character can exchange FP for MP at any point, at a rate of 4 MP per FP.  This replaces the normal rules for Extra Effort in Combat.  If using The Last Gasp, you may instead exchange AP for MP

Stunning:  A character who is Stunned has a base 6 MP, rather than 20, and is at -2 to all defenses.  He can still spend (and acquire, from Acrobatics or FP/AP) bonus MP normally, however.  This allows him to attempt clumsy attacks or defenses, or stumble away at half Move.


MP may be spent as follows.

Attack:  Making an attack costs 6 MP, which allows an attack at -4 or -(skill/2-3) to skill, whichever is worse.  Each additional MP gives a +1 to attack, to a maximum of +4 or +(skill/2-3) to base skill, whichever is better, for melee attacks; ranged attacks are limited to a maximum of +2 or +(skill/4-1.5), whichever is better.  MP can also be spent to reduce or negate penalties other than those resulting from use of Deceptive Attack, Setup Attack, Predictive Shot, or similar - every 2 MP negates up to -3 in penalties.  Penalties for hit locations and similar are still limited to 1/2 the initial penalty being negated, however.  For melee attacks, you may add one - and only one - extra yard of Reach to your attack for 4 MP (optionally, use "A Matter of Inches," with each step above Average being -1 MP to cost, each step below Average being +1 MP to cost).  For a ranged attack to benefit from a previous Aim, you must spend an additional 2 MP.

Note the above is a one-time cost - to get additional attacks, use Dual Weapon Attack, Rapid Strike, etc, at the normal penalties.  MP invested to reduce penalties can eliminate these as well.

Damage:  If making an attack, damage can be improved.  Every 2 MP is +1 or +0.5/die to damage, whichever is better.  Additionally, melee impaling weapons that strike a target can be purposefully wrenched out to cause additional damage.  This costs at least 1 MP and calls for an attack roll, at -4 relative to the first.  This can be defended against normally, with a successful defense meaning the weapon is pulled out without further injury, but the defense suffers the full Shock penalty of the initial injury.  Swing impaling weapons are harder to do this with, due to poor leverage, calling for an additional -3 to skill (total -7).  Barbed weapons are also harder to remove, suffering the same -3.  Every MP results in 20% of the initial injury being suffered as the weapon is pulled out, to a maximum of 60% for 3 MP.  For barbed weapons, this is instead 30% per MP, to a maximum of 90% for 3 MP.  For swing impaling and barbed weapons, dealing 60% or more injury prevents them from being stuck in the target.

The character can regain some MP by dealing less damage.  This is 1 MP for -1/die, 2 MP for -2/die, and 3 MP for causing no damage.  A no damage attack can be a tap (for delivering touch effects) or a Feint or similar.

Defense:   Being able to defend costs 6 MP, which sets all defenses at 7 or Defense-2, whichever is worse.  Increasing defenses follows a stepwise pattern.  Every 2 MP negates -1 to all defenses from the above until Dodge reaches its normal state.  Once Dodge is at its full value, every 1 MP negates -1 to all other defenses from the above until they are full.  Following this, you may improve defenses, at a rate of 2 MP per +1 to a single use of a defense, 4 MP per +1 to all uses of a given defense, or 8 MP per +1 to all defenses.  You may also spend 4 MP for a single use of a Double Defense, or 8 MP to make all defenses for the round Double Defenses (a Double Defense is where you get to roll two different defenses against a single attack).

Movement:  You get a free Step or Retreat.  Each additional Step costs 2 MP, to a maximum of half Move (the GM may extend this to full move for chambara and similar games).  Simply moving up to half Move costs 6 MP, while moving up to full Move costs 10 MP.  If making an attack with a ranged weapon, half Move results in an attack penalty equal to half Bulk, while full Move results in an attack penalty equal to Bulk.  Changing Posture costs 10 MP to go a single step (prone->kneeling, kneeling-crouching/standing), 20 MP to go two steps (prone->crouching/standing).

Awareness:  If using Situational Awareness from Tactical Shooting, the default is -4 to the roll for 0 MP (a glance).  Every 2 MP is worth +1 to this, to a maximum of +8 or (skill/2+1), whichever is better.  "Skill" here is the best of Perception, Observation, Per-based Soldier, and Per-based Tactics.

Recovery:  If using The Last Gasp, it costs 2 MP to attempt to recover AP.  This allows for an HT-4 roll.  Each additional MP is a +1 to this roll.

Aim:  If using Take Aim, resolve this as an attack (but with no option for a Damage component).  If not, Aim costs 10 MP.

Concentrate:  For actions that require a roll, treat this much like Attack, above.  You also have Concentration MP (usable only for actions related to the relevant skill) equal to (Skill/2-7), where skill is the actual skill being used.  For actions that require multiple rounds of Concentrate, followed by a roll, you must spend at least 6 MP each round on Concentrate, and roll based on the average MP spent (it's easiest to just maintain the same cost each round, however).  For actions that don't require a roll, Concentrate costs 10 MP.

Evaluate:  Every 3 MP spent on Evaluate negates -1 in penalties from Feints, Deceptive Attacks, etc from the target in question over the round, and also give you an additional 1 MP to spend only against that target next round.  Such Evaluate MP are limited to the greatest of Melee MP, Ranged MP, and Dodge MP.

Ready:  As Concentrate, above.  If Fast-Draw reduces this to a free action, it costs 0 MP.

Wait:  A character can opt to delay his turn with a specific trigger, as usual.  Optionally, he must dictate his Combat Posture (where he is spending his MP) upon declaring the Wait.


Redistributing MP:  A character can reclaim "overspent" MP and spend it elsewhere (typically on either Defense or Evaluate, but Awareness may also be an option).  If the character was prevented from using some amount of MP, he can reclaim up to half of it.  If he did use it, but had a higher MoS than needed, he can reclaim up to a third of the excess.  Note this latter option essentially retroactively drops your effective skill, so you may not want to do it if you expect to make further rolls against that skill, and you can only reclaim points based on your lowest such roll during the round.



Let's run an example character through the paces.  He's a rifle-toting TL 5 mage named Jack, with ST 13, HT 12, Dodge 11 and Move 7.  His best melee skill is Spear 16 (for bayonet fighting), his best ranged skill is Guns(Longarm) 18, he has Acrobatics 14, Path of Energy 20, and Fast Draw (Ammo) 18.  His best Awareness skill is Per-based Soldier, at 14.  He also has Bayoneteer (no Guns penalty for having an attached bayonet), Combat Reflexes, Ritual Adept, Ritual Mastery (MTC Shot), and Quick Reload (Muzzleloading Rifle).  He could also have a Hold Spell Perk (letting him finish gathering energy for a ritual, then wait to actually cast it, rather than doing so immediately), but I think that functionality is balanced enough to be the RPM default.

He starts with 24 MP (20 base, +4 for his high Dodge).  He has Melee MP 2 (1 for high skill, 1 for high Parry) and Ranged MP 2 (for high skill).  When using Path of Energy, he has Concentration MP 3 (for high skill), or 4 if using it with MTC Shot.

At base, Jack can attack with his bayonet at skill 11 or his rifle at skill 12 for 6 MP, defend at 7 for 6 MP, or move up to 4 yards for 6 MP.  If not spending anything on Awareness, he rolls against 12 there.  He can attempt to recover AP with a roll against 8 (HT-4) for 2 MP.  He can add up to +10 (+5 from base) to his attack with the bayonet for 10 MP, or +12 (+6 from base) to his attack with the rifle for 12 MP.  He can boost both Dodge and Parry to 11 (base Dodge, Parry -1) for 8 MP, boost Parry to 12 (base Parry) for another 1 MP, after which he uses the normal (2 MP per single +1, 4 MP per outright +1 to single defense type, 8 MP per +1 to all defenses).  And so on.

Let's say Jack is in a long battle, and has exhausted his supply of MTC Shot Charms (MTC Shot is a 30 energy ritual that enhances the burn of gunpowder, markedly increasing damage).  He gets behind some cover and starts loading a normal bullet while gathering energy for MTC Shot.  Reloading with Fast Draw is going to take him 12 seconds.  Of his base 24, he spends 6 on Concentrate, 6 on Ready, and 12 on defense.  He spends all 4 of his Concentrate MP on Concentrate, boosting it to 10, and both points of Ranged MP to boost the Ready to 8.  As there's no equivalence for his Melee CP, those are functionally wasted.  He continues this for 5 rounds without issues, calling for a roll against MTC Shot.  With only 10 MP invested in it, he's rolling against an 18.  He gets a 10, gathering 8 energy.

He continues on, but when he rolls an 8 against his Awareness 12, he notices a sorcery-twisted, misshapen husk of a man charging him with an oversized sword.  Rather than fight with his back to the wall, he temporarily stops reloading, keeps spending 10 MP (6 base + 4 Concentrate MP) on his ritual, spends 2 base MP for an extra Step, spends 12 (10 base +2 ranged) on Defense (this also means he automatically spends his 2 melee MP on defense), and the remaining 8 base on an attack, charging and thrusting at the creature at skill 13.  He scores a hit, but it bats his weapon aside and steps in with a swing.  He burns 1 FP, spending 2 MP on getting a +1 to this Dodge, and 2 MP on getting an extra Step, which he uses to Retreat, for an effective Dodge 14, letting him get out of the creature's way.  Some bullets are hitting the ground near him, so he knows he needs to end this quickly and get back to cover before his foes decide to aim first, so he eschews defense this next round - he still spends 10 MP on Concentrate, but spends 10 MP (8 base + 2 Melee) on his attack, 6 to increase damage, 2 to rip the bayonet out for still more damage (assuming a hit), and 2 to negate -3 of the penalty to stab the thing in its exposed neck.  That's an attack at 19 (he makes it -4/-2 Deceptive, for skill 15), with a success dealing 1d+6 (3d-1) damage and allowing for an attack at 15 (assuming no Deceptive Attack), with success dealing a further 30% of initial damage.  He rolls a 7 on his attack  The target fails its defense, and he rolls for damage - 12.  This becomes 24 injury, and he rolls against 15 (opts against going deceptive), rolling an 11.  MoS 4 is less than his MoS 8 above, but is enough to reclaim 1 MP (dropping it to MoS 1, the previous to MoS 5), which he promptly reinvests to boost the damage from ripping the bayonet out to 45% (an extra 10 injury).  Thanks to the -4 from shock, the creature fails its defense against this, and suffers a further 10 injury.  It fails its Death Check markedly, and the GM rules Jack very nearly decapitated it ripping his blade out.  Jack uses the free step remaining in his maneuver to get back into cover.

The rest of his time reloading and gathering energy is uneventful - on second 10 he rolls a 9, gathering 9 energy.  On second 14 (he lost 2 seconds killing his attacker) he finishes reloading - as each second he spend actually reloading was with 8 MP, he rolls against 16 to reload, and succeeds - his rifle is ready for shooting.  Without reloading eating up his concentration, he puts the 6 base MP from reloading into Concentrate, boosting effective skill to 24, and the 2 melee/ranged CP into Defense, boosting Dodge and Parry to 11.  He gets another roll against Path of Energy, which spent 4 seconds of the last 5 with skill 18, 1 second with skill 24, for an average of skill 19, which gets reduced to 18 for being the third gathering attempt - a 12 means 6 more energy (running total is 23).  Figuring he'll have the spell ready soon, he changes things up again - 12 (8+4) in Concentrate, for skill 20, 14 (12+2) in Defense, for 11 Dodge/Parry, and 4 in Awareness, boosting that to 14, so he can try to find someone worth shooting.  By the end of those 5 seconds, he's located an enemy mage protected by more of those misshapen men, and is ready to roll to gather again.  Effective skill is 19 (again, -1 for beyond beyond the 3rd gathering attempt), and he rolls a 10 - enough to complete the ritual.

With the ritual ready to go, he takes aim at his target.  He spends 14 (12+2) on Defense, for Dodge/Parry 11, and 12 on Aim, letting him do so at full skill (minus half range).  He succeeds, and rolls well enough that he gets his full Acc (4) against the target.  He's in a decent defensive position, and he has his eyes on a high-value target, so he eschews defenses for the follow up attack.  He needs one last Concentrate to finish his ritual, and also needs an Attack to actually fire the weapon.  10 MP (6+4) is enough for the Concentrate, putting him at skill 18.  He spends 16 (14+2) MP on Attack, 6 to get to attack, 6 to boost skill to full (18), and 2 to benefit from Acc (+4).  Against a target 20 yards away (-10), that's an effective skill of 12.  He rolls an 11 and the enemy mage - who failed to notice Jack taking aim at him - is struck by that magically-enhanced bullet and collapses to the ground.