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Author Topic: High/Low Gravity - When should it start applying??  (Read 286 times)

NeonKnight

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High/Low Gravity - When should it start applying??
« on: 12 November 2019, 11:38:19 »
I've asked this in the RULES QUESTION, but I am hoping to spark a discussion (civil please)...but WHEN exactly should we really start applying the rules from Tac Ops for High/Low Gravity?

The rules on Page 55 (New PDF version), states that worlds with Greater/Lesser gravity than Earth's can impact Mechs/Vehicles movement etc.

My question is...when? The rules here are kind of vague.

Example. Nanking has a Gravity of 1.06 (and in the TOTAL CHAOS campaign scenarios) States to use the High Gravity rules from TacOps.

But, with a low change to Gravity as 1.06, it is not until a Unit has a Walk/Cruise Speed of 9+ that any impact is seen.

The Rule:

Quote
To determine a unit’s movement rates as affected by gravity, divide its Walking (or Cruising) and Jumping MP by the G-rating of the world and round to the nearest whole number (round down at .5).

Walk 7 / 1.06 = 6.6 = 7 (round up)

Walk 8 / 1.06 = 7.54 = 8 (round up)

Walk 9 / 1.06 = 8.49 = 8 (round down)

Worlds Like Detroit (gravity of 1.02) which means a unit needs to have walk/cruise of around 25 or 26 to see a movement impact.

Next would be Jumping Damage. The rules state:

Quote
Make a Piloting Skill Roll, applying a modifier for every full 0.5 gravities above or below 1. For example 0.2 gravity would apply a +1 modifier, while a 2.6 would apply a +3 modifier.

So, worlds like Nanking or Detroit, even with the miniscule 0.06 and 0.02 would impact jumping movement.

Using Comparisons to Planets in our own Solar System, Mars has a Gravity of 0.375 compared to Earth's, so a 100 lb person on Earth weighs 38 lbs on Mars, or that 100 Ton Mech is 38 Tons on Mars.

Using a nice Graphical Gravity Converter I found at: http://howthingsfly.si.edu/gravity-air/gravity-keeps-us-down-earth
We can see that Earth with a Gravity of 1.00 compares to other Planets as:

Mercury - 0.38
Venus  - 0.91
Mars - 0.38
Jupiter - 2.36
Saturn - 0.92
Uranus - 0.89
Neptune - 1.12
Pluto - 0.06

Heck, Even Earth does not have a Constant 1G:

https://en.wikipedia.org/wiki/Gravity_of_Earth

https://www.newscientist.com/article/dn24068-gravity-map-reveals-earths-extremes/

therefore, knowing all of the above, we can then extrapolate that a 100 ton 'Mech on Earth is 100.06 tons on Nanking and 100.02 Tons on Detroit.

In other words, is the 1G cut-off for High/Low gravity a little off? Shouldn't the cut-off be a little more, like maybe don't start Calculating until Gravities are Greater/Lesser that 0.95-1.5?
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Weirdo

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Re: High/Low Gravity - When should it start applying??
« Reply #1 on: 12 November 2019, 12:18:56 »
Use your judgement. If tracking the effects of minor grav differences is a pain, then ignore them until it's drastic enough to noticeably affect ground movement.

And if the gravity affects some units more than others...that's just the nature of the game.

Environmental conditions that affect everything equally do nothing for a game except slow it down, unless it affects win conditions(such as if one side's victory conditions don't actually require killing the enemy). For general clashes, I advise only using environmental conditions that emphasize the difference between various units or swing the balance towards one side or the other.
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NeonKnight

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Re: High/Low Gravity - When should it start applying??
« Reply #2 on: 12 November 2019, 12:34:44 »
Yeah, I'm pretty much going that route (i.e. I'm working on a campaign for Detroit and just recently played the Total Chaos scenario Jinx set on Nanking), which led me down this Rabbit hole, but it obviously still got me thinking.

Yes, I could just say, yeah...No but doesn't really help answer where a good cut-off actually is. And that is the whole...where to actually put a cut-off.
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grimlock1

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Re: High/Low Gravity - When should it start applying??
« Reply #3 on: 12 November 2019, 13:16:25 »
Heck, Even Earth does not have a Constant 1G:

https://en.wikipedia.org/wiki/Gravity_of_Earth

https://www.newscientist.com/article/dn24068-gravity-map-reveals-earths-extremes/
Variations in local gravity are a thing, but for all but a few applications, it's not worth worrying about. We had to prove it when my job went with using an accelerometer as a calibration standard for other pieces of equipment.

If you are doing large scale survey work, it can bite you.  When they were surveying for the Mason-Dixon line, they discovered that the mountains on one side of the line were actually tugging on the plumb bob by just enough to throw them off when the did their verification.

As to when to apply high/low grav rules?  Put 10% of your weight into a backpack and walk around for an hour.  Or look up your car's curb weight, not gross weight, and add 10% of that in cargo or people.  Compare acceleration and gas mileage.
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NeonKnight

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Re: High/Low Gravity - When should it start applying??
« Reply #4 on: 12 November 2019, 13:38:41 »
Variations in local gravity are a thing, but for all but a few applications, it's not worth worrying about. We had to prove it when my job went with using an accelerometer as a calibration standard for other pieces of equipment.

If you are doing large scale survey work, it can bite you.  When they were surveying for the Mason-Dixon line, they discovered that the mountains on one side of the line were actually tugging on the plumb bob by just enough to throw them off when the did their verification.

As to when to apply high/low grav rules?  Put 10% of your weight into a backpack and walk around for an hour.  Or look up your car's curb weight, not gross weight, and add 10% of that in cargo or people.  Compare acceleration and gas mileage.

Yep...that I would see, 10%.

But...put on a completely empty Backpack and walk around for an hour ;)

in other words a huge difference between 90 tons (1 G), 108 tons (1.2 G) and 91.8 tones (1.02 G). If we are going to hung up on that level minutiae, then one could argue as a mech sheds it's tons of ammo/armor it would become more likely to suffer damage from movement.
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Re: High/Low Gravity - When should it start applying??
« Reply #5 on: 12 November 2019, 14:50:08 »
Sounds like you want to do your grav calculations in 0.1G increments, with effects only being calculated for each full tenth of a G above or below normal.
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nckestrel

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Re: High/Low Gravity - When should it start applying??
« Reply #6 on: 12 November 2019, 15:00:55 »
Quote
for every full 0.5 gravities above or below 1
Wouldn't do anything until 1.5 (or .5).  1.06 wouldn't have any full 0.5 gravities above or below 1?
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Re: High/Low Gravity - When should it start applying??
« Reply #7 on: 12 November 2019, 15:16:25 »
Then go by the actual rules, yes. I misread, and thought it said 0.05 gravities. 0.5 means there'd be exactly zero effects between 0.51 and 1.49 gravities. Values closer than that would be solely for fluff reasons, or maybe RPGs.
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NeonKnight

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Re: High/Low Gravity - When should it start applying??
« Reply #8 on: 12 November 2019, 15:39:34 »
Sounds like you want to do your grav calculations in 0.1G increments, with effects only being calculated for each full tenth of a G above or below normal.

Yeah, 10% or 0.1 G works.  Otherwise, it becomes extremely fiddly, and headachy as .01 G (or lower even) has the impact (under the current rules) of affecting Missiles and Ballistic attacks. It also allows (when running ongoing campaigns) of having 'near-Earth' Gravities (+/- 0.9 G) not require a ton of recalculations for no major gain. See Attachment

Don't know if I'd go to 0.5 only as you would really only have the 2 steps above 1: 1.5G and 2.0G, and at 2G you're starting to get close to Jovian Gravity there.

***Updated Chart to go from 1.1G - 2.0G

« Last Edit: 12 November 2019, 15:52:19 by NeonKnight »
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nckestrel

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Re: High/Low Gravity - When should it start applying??
« Reply #9 on: 12 November 2019, 16:20:30 »
The full 0.5 requirement is only on the damage from jumping. 
The other effects (movement speed, damage from running faster than normally allowed) don't have such a limit.

I do like the per full 0.1 addition on the other effects though. 
« Last Edit: 12 November 2019, 16:22:05 by nckestrel »
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NeonKnight

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Re: High/Low Gravity - When should it start applying??
« Reply #10 on: 12 November 2019, 16:54:45 »
The full 0.5 requirement is only on the damage from jumping. 
The other effects (movement speed, damage from running faster than normally allowed) don't have such a limit.

I do like the per full 0.1 addition on the other effects though.

Ah...ok, I think I see what you're saying.
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Iceweb

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Re: High/Low Gravity - When should it start applying??
« Reply #11 on: 12 November 2019, 17:13:29 »
Personally I would ignore any grav differences less than .25 from 1G.  A 10 or 20 percent change in gravity while it sounds like a lot could probably be dealt with by techs on planet by a little reinforcing, and tweaking the actuators.  This is mostly because of the +1 to hit rolls that you get for a gravity difference, which is annoying at small changes of gravity.  It makes the game longer, and I think is unrealistic that it could not be compensated at for under a 25% gravity change. 
Technically even a 1.01 gravity planet would incur the +1 to hit issue for being a different gravity. 

If you were more than .25 difference I would then work in .05 increments for rounding as it gets too fiddly and multiplying by 5s and 10s is just easier.   

Frabby

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Re: High/Low Gravity - When should it start applying??
« Reply #12 on: 13 November 2019, 05:17:47 »
A hard physics simulation approach to big stompy robots means hammering a square peg into a round hole to begin with.

That said, the gravity rules are optional. Use them if and when they improve your game.

For me, that means they are useless in pickup games except for when the players deliberately want to try them out.
They may be useful to have in a fixed scenario, in order to tilt game balance in other ways than BV or terrain. I did this myself with the BattleCorps scenario "Twins", though explicitly as an optional rule. (Another optional rule from my submission was cut from the published scenario.)
Best use is probably in campaign play. As a GM, I was a stickler for details and if my players operated on a world with a different gravity then they had it coming if they didn't take gravity modifiers into account for unit selection and tactics. The OpFor certainly did. (Though we used house rules for gravity. I don't think there were official rules at the time.)
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