Scale system for EP

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yuriAza yuriAza's picture
Scale system for EP

So as we all know, one of the very few weaknesses of EP is its difficulty with big things, like anything much bigger than a motorcycle or person that's not a set piece. the Size traits definitely help, but armor and durability quickly become unfun as the numbers rise. I'm trying to remedy this with a scale system that keeps the numbers manageable at all sizes while keeping interactions between them realistic, so here goes:

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--(rules voice)--

There are 5 scales: I(nfantry), P(owered armor/car), M(echa/fighter jet), F(rigate), and C(apital); each is five times (x5) the previous one (625I:125P:25M:5F:1C). Both objects and their equipment/augmentations can have their own scales.
Convert damage (not Durability or Armor) before rolling it, like this (where X is a given scale, Y is the scale above X, and Z is the scale above Y):

1d10X DV → 1Y DV
1d10Y DV → 5d10X DV
5X DV ↔ 1Y DV
<5X DV → 0Y DV
<25X DV → 0Z DV
<5d10X DV → 0Z DV

(In general, dice convert to dice, modifiers convert to modifiers, and you multiply or divide by five and round down for each summed part. Notice that dmg “stabilizes” as it converts in both directions.)

Hybrid damage (AOE, explosions, environmental effects, anti-vehicle weapons, and other things that hurt in rough proportion to size) has multiple consecutive scales (the most common types IP, IPM, or MFC), and matches scales as best it can before converting.
Criticals (, called shots, etc.), rather than ignoring armor, reduce it one scale (ie. divide by 5 and round down) or ignore it if it was I.
All P scale objects are considered to have the Large Size trait, and M scale objects to have the Very Large Size trait (but see below for exceptions to those trait’s rules).
Attackers suffer -10 to hit per scale their target is smaller than the weapon they are using (in addition to Small Size or Very Small Size modifiers); they similarly gain +10 to hit per scale their target is larger than their weapon (this includes and does not stack with Large Size or Very Large Size modifiers).
Collision/fall damage is hybrid damage whose scales range from I to the scale of the colliding object (also apply this damage individually to each passenger), size related traits do not affect the collision damage received by things that are larger than I scale.
During grappling or other direct contests of strength (ie. where both actors would only be able to use a multiple of SOM or a skill linked to it, and which are not attacks), if one object is a scale larger than the other, the larger scale object receives +30; if the two objects are two or more scales apart, the larger scale object will usually automatically succeed and beat the other object.

DM tips for making scales fair:
- Scale factors of x5 are a big hurdle, but a realistic one which is surmountable with preparedness
- Remember +5 DV per 30 MoS (+1 DV at one scale higher) and ±10s to hit
- Treat things one scale above the party as minibosses, treat things two scales above more like puzzles to be circumvented or exploited
- M scale things (mecha, helicopters) can’t really operate properly in urban areas
- Most combatants carry a mix of weapons of their scale and the two below it (usually only 1 or 2 built-in/natural weapons per scale)
- Give players access to grenades and/or anti-armor hybrid damage weapons when/if they need them and give them time/warning to prepare (knowledge tests, mission briefings, loud rumbling noises, etc.)
- AOE damage is often hybrid damage

--(/rules voice)--

My goal is to be as realistic as possible and have scales be all that is needed to differentiate the very big from the very small (all the stat ranges stay the same). A group of I scale PCs going up against a P scale tank or powered armor is very much intended to go like the climactic fight in the original Ghost in the Shell movie.

Granted, really using this system means making new stats besides just the military craft. Man portable IP anti-tank and IPM anti-air missiles should be as common as they are in real life, and vehicles would usually be armed with a mix of weapons of their scale and the two below it: while shooting a guy out in the open with the main gun of a tank is overkill, it's a trick shot and it makes more sense to just shoot him with the tank's machine gun turret (mechanically, you're trading 4/5th of your damage output (which you don't really need for a kill) for +10 to hit).

I chose a scale factor of 5 because it was a common house rule for CthulhuTech (which this subsystem is admittedly inspired by, along with EarthScorpion's A Strangely Eclipsed Aeon) and because 5.5 is the average result of a ten sided die, which makes the math that much neater. Also notice that the possible damage rolls turn into tighter bell curves when you convert scales in either direction.

I made this subsystem to be used with a few other rules of mine for crashes, piloting, and mecha-vs-mecha fights with destructible terrain, but I think it should be able to stand on its own. Also notice that if all objects are I scale, nothing changes from RAW and you can still use the Size traits as normal.

What do you guys think? Got any ideas for stats for vehicles or anti-vehicle weapons that would be good for playtesting? Is 5 scales with a scale factor of 5 a good fit?

CordialUltimate2 CordialUltimate2's picture
It works!!!

It works!!!
It at least alleviates he issue of daitya having more durability than Fenrir.

It is good to run ocassionnal encounter with heavy armor. Treating all seeker weapons as at least one scale higher, and normal full sized as at least 2 scales higher depending on their payload. Anti-vehicle anti-armor full sized seeker missile can hurt C-scale objects.

I would rule that damage from bigger weapons doesn't get multiplied when targeting smaller objects and just adjust the damage of the weapon along with the durabilities of the vehicles. This would make the system somewhat exponential, but it would be easier for GM to adjust.

Now that I thought about it as RPG systems are notoriously unwieldy when running fights on scales other than infantry scale. And any enemy you encounter that is a mecha or a tank or a frigate you can just rule that mecha is immune to most antipersonnel weapons, tank is immune to anything but dedicated anti-armor weapons
And a frigate? You can try to scratch their paint with that seeker launcher of yours. You need at least artillery grade weapons. Finally some use for gunnery skill.

So the fights between differently scaled combatants would be better handled by GM adjudication, than a system. If you want to run combined arms warfare just adapt Eclipse Phase to some different system. I hear that Warhammer Dark Heresy is a nice percentile based system that has anything between servo skull, and a titan (giant ass robot).

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CordialUltimate2 CordialUltimate2's picture
It works!!!

Double post

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yuriAza yuriAza's picture
Thanks for the input!

Thanks for the input! (My responses in the order you brought up the original points:)

I totally agree with you on seekers, especially given how they are described in the setting (although the specific implementation would be that they are I scale weapons (so a single person can still use one) but deal IP (for seekers) or IPM (for full missiles) damage). Same goes for grenades. (By today's 21st century standards, a grenade deals IP damage, a man-portable missile deals IPM damage, and a cruise missile (which really can't be mounted on an I scale platform ie a person) deals MFC damage.)

Damage not getting multiplied for smaller scale targets is exactly what the hybrid damage mechanic is for, so seekers and grenades being dealing IP hybrid damage gives them more punch against vehicles (which are now free to go bigger by having larger scales rather than just adding DUR), but has no effect on infantry vs infantry combat.

It would be simple to say that tanks etc. are immune to small arms, but in reality they aren't and it would be harsh on players (allowing chip damage makes being unprepared a big problem, rather than a death sentence). It would make combat against armor be just puzzle solving and less about tactical advantage, and the principle would get clunky once those tanks started shooting at each other and at even bigger things.

I like EP. And I especially like EP because of its core skill resolution mechanic (and I was never into complex hit tables). And DM adjudication may be ok for a one-off against a tank, but it's not enough for a real modern battlefield or a space battle.

(And besides, Gunnery is for drones and turrets, not just vehicles, which don't have to be set pieces anymore.)