How to run tactical combat on the Plane of Air?

Question

My party recently got themselves accidentally transported to the Plane of Air by way of a cursed throne that once belonged to a cloud giant. While there, I intend to run at least one combat where there is no "ground" to act as a reference.

The Plane of Air uses Subjective Directional Gravity, where inhabitants of the plane determine their own “down” direction. Under these conditions I believe that each creature will fall at least 150 feet per round in a direction (mostly) of their choice. I'm expecting this to cause some issues while running tactical combat.

I normally run combat on a square-grid battlemat, 5 feet per square. My party has struggled with theatre-of-the-mind or less structured combat in the past. I don't think that will work here due to the scale involved. I can change the scale to accommodate a larger map but that doesn't entirely solve the problem.

My main concerns are:

1. Creatures can travel enormous distances extremely quickly. Combat can be spread over more than 1000 feet in 3 dimensions within 2 rounds.
2. Managing range for spells and ranged attacks. While "falling" it is difficult for the players to control their positioning to allow them to use ranged effects.
3. Three-dimensional combat with no clear reference system might be disorientating.

How do I manage airborne combat in a plane with Subjective Directional Gravity?

Answer 1

Get rid of the grid

We had a very similar situation recently, where our team had an air battle against flying foes with high movement rates.

A grid won't work, because unless you use a barn floor for the map, creatures with high flying speed will be off that grid in no time. You could use larger feet per square to rein it in, but in my experience (and as you say yourself), this still will not help:

Once you get into calculations of height and distance, as described in Niko's answer, you'll be spending your whole session doing trigonometry. I know, because we did. No fun. And as long as you use a grid, it is really hard to get away from that. We tried to spitball it all and loosely track movements on a large-scale 2-D grid, but as soon as it did matter if you can reach or shoot someone, out came the calculators to demonstrate to the DM that the distance was different than what he thought. And from what you say "the system should be prepared for the fact my players will likely make it 3d", your players are no different. So any kind of grid will not work.

The Air Combat Mini-Game

If this is a one-time situation, then all you need to achieve is to represent the alien environment in a fun way. To make this an exciting, workable encounter, you can use another system instead of the standard movement rules, which never were made for 3-D, a new mini-game that reflects the strange environment.

Having a mini-game also may help your players if they are not able to handle pure theatre of the mind well (we have the same issue): It provides clear, if different, rules how things work.

As the environment is very different from what your player characters are used to, and as you say, disorienting, with new mini-games rules the players may have fun working out in real-time how to effectively combat under these changed rules, just as their characters are trying to work out how to combat under these changed conditions.

What is a good mini game?

What worked for us was entirely getting rid of the map, and just using a concept of zones for combat, as Dresden Files uses. You define a couple of zones like "at the heart of combat", next to it "close to combat", next to that "in the distance", and after that "lost out of reach". The last one is special, you cannot pursue someone who gets there, and combatants there are not considered in the same zone, but you can get back into "in the distance" from there.

Melee attacks only happen in the same zone, as do short range (less than 100 feet) missile or spell attacks, longer range weapons can only attack into adjacent zones. Movement only can move you from one zone to the next if you spend a full round, or within a zone into melee if you spend a normal move.

To account for the special gravity (which we did not have), you might add something like a "dropped to the side" zone. If you cannot fly, make a saving throw to see if you can steer your falling movement the way you want (into melee to attack, or to get to another zone), else you move to the "dropped to the side" and then after that "lost out of reach".

There are, of course, many other ways to handle such a mini-game. The point is that it should be abstract enough to shield you from getting into distance calculations, simple enough to learn in a minute, and complex enough to allow for some tactics.

Answer 2

Fighting in the plane of air without a fly speed is pretty tricky, as you've mentioned it'd mostly be a lot of falling and fumbling around with range and disorientation. That said there should be a few ways to manage an interesting encounter that isn't a nightmare to run while still staying withing the rules of Pathfinder.

A Bit of Scenery

Having a battle in a vast empty expanse is somewhat uninspiring and doesn't help players or the GM keep track of where things are. By having some amount of "terrain" or other features that characters can be positioned in reference to, that may help keep things straight and address your 3rd concern.

Flying creatures have great advantages here, though nonnatives of all sorts might find themselves constrained by the lack of solid ground. Such material does exist, in the form of great chunks of drifting ice originating from the adjacent Plane of Water and magically suspended hunks of earth and crystal—but such places are few and far between.

One option is to have the fight in an area with these great chunks of drifting ice and/or hunks of earth and crystal, allowing non-flying characters to subjectively fall between islands if they need to move around. On a battle map, putting height markers or dice next to these "islands" could help folks wrap their minds around what's happening in the battle.

This also has the advantage of making a fight more tactically interesting than just an open sky, as even characters with flight could be interested in hiding behind these islands or using them for cover. Even just one moderately-sized island could showcase the unique considerations of the plane, allowing walking characters to circumnavigate the tiny planet thanks to the subjective gravity.

An less intrusive option could be to position a few large clouds throughout the area, keeping track of characters in relation to things like "between those two clouds" or "one turn of falling past that cloud". This works far better with actual flight speeds, but it could still be helpful if the fight stays centered on one particular area for some time.

And to your concern #1, keeping the fight centered on a particular area would be very helpful to avoid having characters fall hundreds of feet away from each other. Putting some critical plot item/NPC where you want to center the battlefield could ensure the party stays focused on the action instead of falling off the map.

Chase Sequence

Another option would be for the party to fall in one particular direction and have flying enemies give chase. Either the enemies won't be able to catch up or the party will effectively be standing still on the map as they fall and the enemies move relative to them. Definitely the most likely option to result in chaos if anyone decides to split the party, so I wouldn't recommend this unless the party decides to try fleeing a battle.

Everybody can Fly

A pretty good option might be to just give the players all flight of some variety before a fight kicks off, maybe with some reusable magic item like a wand of fly that they find. This should reduce the havoc that selectively falling will cause on the battlefield, while also giving more control to the players.

This does make for complicated battlefields but putting tokens on dice representing their altitude could help with making a good battle map. And this would offer the most control for your players if they wish to attempt ranged attacks/spells as your 2nd concern.

Player's would still be able to stop flying and start falling at any time, so this really doesn't prevent the first or third concerns of yours. Some mixture of flight and focusing the battle around something might be the best bet at addressing all three of your main concerns.

Answer 3

We Apply Mathfinder. Particularly, the round down, Pythagorean theorem and conditional formula >=.

A Pythagorean theorem has sides A, B and C. C being the hypotenuse.

BASIC

Suppose A, your character, is on the ground and wants to attack a flying creature. Find the distance between your character and the target and then find the altitude of that target.

Suppose we've found out that distance of target is 30ft. and altitude/fly height of the target is 45ft. The formula would be like this: 30² + 45² = N². Your character's position can be A or B and the Pythagorean could be upside down, your call. The hypotenuse is 54.08326. We round down that to 50 since Pathfinder uses a round down system when a decimal is involved as a result of an equation and squares use multiples of 5.

Now that we have 50, the next step is to compare it with the ranged increment or a spell with range requisites. We'll use ranged composite longbow as an example. The conditional formula would be:

If Bow-Range-Increment >= Rounded-down-Hypotenuse, then WITHIN RANGE. Otherwise, apply INCREMENT PENALTY to attack roll.

For ranged spells, the maximum limit as described is the limit.

If Spell-Max-Range >= Rounded-down-Hypotenuse, then WITHIN RANGE

As GM, either do not allow casting a spell beyond that range or allow but spell fails because of range.

WHAT IF BOTH ARE FLYING

Suppose we've found out that distance of target from character is 30ft, the altitude/fly height of the target is 45ft. In addition, character is flying at an altitude of 60ft.

Find the lowest altitude among character and target and subtract it by that same amount so that we get a ZERO. In our example, 45ft. becomes ground zero while 60ft minus 45 becomes 15FT. Thus, for purposes of computation. The formula is 30² + 15² = N².