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If a battle were to be fought on a high gravity world - how would you alter the rules?
Would a -1 to all Movement characteristics be unfunctional?
Note: Balance doesn't matter here, I'm just looking for rules which could represent the high gravity, and which could be fun to play with. (Balance aside)
Andy Chambers wrote:
To me the Chaos Space Marines needed to be characterised as a threat reaching back to the Imperium's past, a threat which had refused to lie down and become part of history. This is in part why the gods of Chaos are less pivotal in Codex Chaos; we felt that the motivations of Chaos Space Marines should remain their own, no matter how debased and vile. Though the corrupted Space Marines of the Traitor Legions make excellent champions for the gods of Chaos, they are not pawns and have their own agendas of vengeance, empire-building vindication or arcane study which gives them purpose.
Ouch -2 to movement! That's some penalty! Lower WS and BS should also mean significantly fewer casualties during a battle!
Andy Chambers wrote:
To me the Chaos Space Marines needed to be characterised as a threat reaching back to the Imperium's past, a threat which had refused to lie down and become part of history. This is in part why the gods of Chaos are less pivotal in Codex Chaos; we felt that the motivations of Chaos Space Marines should remain their own, no matter how debased and vile. Though the corrupted Space Marines of the Traitor Legions make excellent champions for the gods of Chaos, they are not pawns and have their own agendas of vengeance, empire-building vindication or arcane study which gives them purpose.
Chaospling wrote: If a battle were to be fought on a high gravity world - how would you alter the rules?
Would a -1 to all Movement characteristics be unfunctional?
Note: Balance doesn't matter here, I'm just looking for rules which could represent the high gravity, and which could be fun to play with. (Balance aside)
I'd probably do something like...
(1) Models get -1" to their movement, unless they have the Fly keyword, in which case they get -2".
(2) Vertical distance going up is doubled, but going down is halved.
(3) The Grenades Stratagem has its range halved.
(4) Weapons have their max range reduced by one-third, to a minimum of 3".
1 is simple.
2 is a little more complicated.
3 is more just for fluff.
4 might need a bit of math, but you can do it all pre game.
Clocks for the clockmaker! Cogs for the cog throne!
Break out the Oldhammer rules, and make everything difficult terrain.
Half movement for everything! A guardsman's dream!
BorderCountess wrote: Just because you're doing something right doesn't necessarily mean you know what you're doing...
"Vulkan: There will be no Rad or Phosphex in my legion. We shall fight wars humanely. Some things should be left in the dark age." "Ferrus: Oh cool, when are you going to stop burning people to death?" "Vulkan: I do not understand the question."
– A conversation between the X and XVIII Primarchs
Chaospling wrote: If a battle were to be fought on a high gravity world - how would you alter the rules?
Would a -1 to all Movement characteristics be unfunctional?
Note: Balance doesn't matter here, I'm just looking for rules which could represent the high gravity, and which could be fun to play with. (Balance aside)
I'd probably do something like...
(1) Models get -1" to their movement, unless they have the Fly keyword, in which case they get -2".
(2) Vertical distance going up is doubled, but going down is halved.
(3) The Grenades Stratagem has its range halved.
(4) Weapons have their max range reduced by one-third, to a minimum of 3".
1 is simple.
2 is a little more complicated.
3 is more just for fluff.
4 might need a bit of math, but you can do it all pre game.
I’d actually say double for going down as well, as you’d have to brace your legs and recover from the drop. Given the two separate stories about marines in terminator armor falling through stairs and needing a excavation crew to pull them out while their battle brothers laughed at them, I wouldn’t be surprised if units had to account for it and take time to scan the floor for safe spots to land even more than before.
This message was edited 1 time. Last update was at 2025/09/30 00:05:21
One day I will have something funny enough to be in a signature.
Chaospling wrote: If a battle were to be fought on a high gravity world - how would you alter the rules?
Would a -1 to all Movement characteristics be unfunctional?
Note: Balance doesn't matter here, I'm just looking for rules which could represent the high gravity, and which could be fun to play with. (Balance aside)
I'd probably do something like...
(1) Models get -1" to their movement, unless they have the Fly keyword, in which case they get -2".
(2) Vertical distance going up is doubled, but going down is halved.
(3) The Grenades Stratagem has its range halved.
(4) Weapons have their max range reduced by one-third, to a minimum of 3".
1 is simple.
2 is a little more complicated.
3 is more just for fluff.
4 might need a bit of math, but you can do it all pre game.
I’d actually say double for going down as well, as you’d have to brace your legs and recover from the drop. Given the two separate stories about marines in terminator armor falling through stairs and needing a excavation crew to pull them out while their battle brothers laughed at them, I wouldn’t be surprised if units had to account for it and take time to scan the floor for safe spots to land even more than before.
Fair! Probably simpler that way too.
Clocks for the clockmaker! Cogs for the cog throne!
You could argue that the lethality would either end up the same or worse due to gravity.
Any injury that affects your movement could see you on your back taken out of the game, when under normal gravity you could push through it. You are more vulnerable to being disabled under higher gravity.
So you could argue that you get -1WS to hit, but the target is at -1T due to the increased chance of being disabled and removed from play.
There might be less absolute lethality, but in terms of taking you out of the fight for the purposes of winning the game, it could be more.
Doubling movement going up or down terrain means that most units basically can't utilize the second level of maybe literally every ruin at my local GW. Or at least, they can't leave the second floor after being deployed there.
Vertical movement penalties also raise interesting (and math-y) questions about trying to use Fly units' diagonal movement to get over a ruin.
JNA's approach to movement penalties is probably a good way to go. -2" is just brutal on the slower units in the game. Probably don't want necrons moving a measley 3". Amusingly, -2" to fly units does mean that spore mines are reduced to moving 2" per turn.
Weapons reducing their maxed range by a third works pretty well mechanically. The fluff weirdness there comes in with energy weapons. I'm not sure a lasgun's projectile would be pulled earthward by the extra gravity the way a bullet would be. Then again, I guess you could argue the range penalty is more about the difficulty of aiming well in unfamiliar gravity.
The tricky thing about high gravity rules, I think is coming up with something that captures the fluff but isn't just a slog to actually play with. Like, some kind of movement penalty makes sense, but you don't want to spend the whole game sighing because your army feels like it's moving through molasses.
I'd be tempted to do something like:
* All guns have their BS reduced by 1, but they also all gain Heavy.
* -1" movement. Another -1" if you opt to move more than 8" (highest infantry speed I'm aware of outside of a solitaire or jump units.). Another -1" when you advance. So you're noticably slower, but the slowness scales up with your overall movement so that we're not just slowing necron warriors to a crawl.
The idea being that you end up with units being incentivized to set up firing lanes and hold still and generally feel "heavy", but units with Assault weapons or good movement stats will proportionately feel quite a bit faster than their opponents.
Fluffy but completely unfair rules: Let harlequins straight up ignore all these penalties because flip belts (grav tech) is a part of their basic kit. Maybe even let aeldari/cron/tau tanks ignore it since those all use anti-grav tech that presumably counters at least the movement part of the above rules.
ATTENTION. Psychic tests are unfluffy. Your longing for AV is understandable but misguided. Your chapter doesn't need a separate codex. Doctrines should go away. Being a "troop" means nothing. This has been a cranky service announcement. You may now resume your regularly scheduled arguing.
My 9th edition theatres of war project, use or copy/update at your leisure although I am afraid I never got to a high gravity world. What I tried to do with all of mine is to have downsides paired with upsides, so if I nerfed shooting I would have a different buff to shooting. https://www.dakkadakka.com/dakkaforum/posts/list/796068.page
A possible effect of fighting on a spaceship I came up with was -2 to charge/advance or -2 to Movement depending on if the spaceship was doing evasive manouvres or putting out maximum thrust.
You could have people go splat when they jump down, like take a S3 hit when you jump down from 4+" unless they have FLY. You still allow for vertical fighting, but your guys are going to hurt doing it. Then increase the power of firing from a high point. Taking the high ground becomes a scary but powerful prospect. Have charges be slower, but carry more impact so you get +1 S on the charge but -2 to charge distance.
It depends on what your goal is I think, fun and fluffy is hard to say because a game with little movement is generally a bad one and having battlefield downsides is just inherently anti-fun and something a game designer might try to avoid, at the same time it would be a super common battlefield feature. Something else to consider is whether players know what they are getting into, if they do then you can be more heavy-handed.
Here's what ChatGPT came up with:
Spoiler:
Here’s a full Theatre of War: High Gravity World ruleset for Warhammer 40,000 9th Edition, written to mirror the style, tone, and scope of your Low Gravity World rules while providing an opposite but thematic play experience.
HIGH GRAVITY WORLD
The crushing pull of a massive world makes even the simplest act of movement a struggle. Armour strains, lungs burn, and war machines groan under their own weight. For the defenders of such planets, the gravity itself is a weapon, slowing invaders to a crawl and sapping their strength. For attackers, only the strongest—or most desperate—armies will dare wage war beneath such crushing skies.
When fighting a battle on a high gravity world, the following rules apply:
HEAVY AS LEAD
The weight of armour and weapons drags even the strongest warriors down.
Reduce the Move characteristic of all non-TITANIC units by 2" (to a minimum of 1").
Units cannot pile in or consolidate more than 2".
STRAINED MACHINES
Engines and weapons fight against unbearable pressure.
VEHICLE and BIKE units subtract 1" from Advance and Charge rolls.
Ranged weapons with a Range characteristic of 36" or more reduce their range by 6" (to a minimum of 18").
BATTLEFIELD TWISTS
Before the battle, one player rolls one D3 and consults the battlefield twists table below, or both players can agree on the most suitable option. This roll cannot be re-rolled unless otherwise specified.
Crushing Atmosphere: The air itself resists every action.
All units suffer -1 to Advance and Charge rolls.
FLY units subtract 2" from their Move characteristic.
Pulverising Storms: High gravity storms pound warriors with stone and shrapnel.
At the end of each Battle Round, roll one D6 for each unit that is not wholly within a terrain feature. On a 5+, that unit suffers 1 mortal wound.
Core-Tremors: The planet’s tectonics strain under immense mass.
At the start of each battle round, roll one D6. On a 1-2, all units subtract 1" from their Move characteristic until the end of the round.
MYSTERIOUS OBJECTIVE MARKERS
If you are fighting a battle that uses any objective markers, before deployment, one of the players should roll one D3 and consult the mysterious objective markers table below to see what additional rules apply to the objective markers on the battlefield. This roll cannot be re-rolled.
Dense Ore Vein: The ground here is rich but impossibly heavy.
Units within 3" of this objective subtract 1" from their Move characteristic but gain +1 to armour saving throws.
Gravity Sinkhole: The pull of gravity is even stronger here.
Units within 3" of this objective count as being within Difficult Ground.
Stabilisation Beacon: Ancient technology helps counteract the world’s immense gravity.
Units within 3" of this objective ignore penalties from Heavy as Lead and Strained Machines.
TERRAIN TRAITS
Before the battle, one player should roll one D3 and consult the terrain traits table below, or both players can agree on the most suitable option.
Reinforced Structures: Buildings and ruins on such worlds are braced to withstand crushing pressure.
INFANTRY units wholly within Ruins gain +1 to their armour saving throws.
Collapsed Ravines: The immense weight of stone and soil often causes sudden collapses.
If a unit Advances into or through an Area Terrain feature, roll a D6. On a 1, the unit suffers D3 mortal wounds.
Mag-Grav Fields: Strange gravitic distortions pool around certain terrain.
Units within 6" of this terrain cannot Advance.
STRATAGEMS
If your army is Battle-forged, you have access to the Stratagems shown below whilst using this Theatre of War.
UNYIELDING RESOLVE – 1 CP
Even under unbearable gravity, warriors steel themselves against the crushing weight.
Use this Stratagem at the start of your Movement phase.
Select one INFANTRY unit. Until the end of the phase, that unit ignores the Heavy as Lead penalty to its Move characteristic and pile-in/consolidation distances.
REINFORCED SYSTEMS – 1 CP
Vehicles are pushed beyond safe limits to endure the world’s deadly pull.
Use this Stratagem when a VEHICLE model from your army is targeted by an attack. Until the end of the phase, improve its armour saving throws by 1 (to a maximum of 2+).
CRUSHING MIGHT – 1 CP
The strength required to fight in such conditions can be turned against one’s foe.
Use this Stratagem in the Fight phase.
Select one INFANTRY or MONSTER unit from your army. Until the end of the phase, improve the Strength characteristic of models in that unit by +1.
Regarding Movement: How about it scales to the size/weight of the model?
1 Wound: No Penalty
2-10 Wounds: Reduce Movement by 1.
11-20 Wounds: Reduce Movement by 2.
And so on.
Models with the Fly keyword are unaffected.
Andy Chambers wrote:
To me the Chaos Space Marines needed to be characterised as a threat reaching back to the Imperium's past, a threat which had refused to lie down and become part of history. This is in part why the gods of Chaos are less pivotal in Codex Chaos; we felt that the motivations of Chaos Space Marines should remain their own, no matter how debased and vile. Though the corrupted Space Marines of the Traitor Legions make excellent champions for the gods of Chaos, they are not pawns and have their own agendas of vengeance, empire-building vindication or arcane study which gives them purpose.
Chaospling wrote: Regarding Movement: How about it scales to the size/weight of the model?
1 Wound: No Penalty
2-10 Wounds: Reduce Movement by 1.
11-20 Wounds: Reduce Movement by 2.
And so on.
Models with the Fly keyword are unaffected.
Makes sense with the square cube law. Most models with over 10 wounds would have high enough Movement to not get completely gutted by -2 either, I would probably stick with -2 instead of adding a -4 for models with 32 wounds, just for simplicity, although you might not get the idea across in that case. Remember it would be a Wounds characteristic, so it does not get modified when units are damaged. Flying units would use tonnes of extra resources flying. Do you want a tonne of flying units in your high grav games? Maybe it makes sense to you that armies would bring anti-grav tech maybe not. You could add additional rules to make it suck (some of the time) to have FLY or be an AIRCRAFT.
Glancing through my 3rd edition 40k rulebook.
High gravity worlds say that normal movement is reduced by 1d6" , or, you would roll 3d6 and pick the highest for moving through open ground, and only roll 1d6 for the distance you move through difficult ground.
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