# How do inanimate objects react in subjective gravity?

I am thinking of running a campaign that takes place on the Elemental Plane of Air with the PCs being sky nomads. Naturally, they'll have a ship, but I am not sure how inanimate objects react when in subjective directional gravity.

Do objects float until something pushes them? Are objects only weighed down when creatures attend them? Is an object's gravity decided by the majority of the people in it, on it, or around it?

• Can you provide a reference to what causes this subjective gravity in the plane of air? Commented Apr 27, 2018 at 13:36
• @royalmurder (Links to those descriptions added by the editor.) Commented Apr 27, 2018 at 13:40

Subjective Directional Gravity states the following:

The strength of gravity on a plane with this trait is the same as on the Material Plane, but each individual chooses the direction of gravity’s pull. Such a plane has no gravity for unattended objects and nonsentient creatures.

So, as the objects themselves provide are free of gravity in and of themselves, the only times they would be affected by gravity would be when attended by a sentient creature. In which case they would behave as per the attending creature:

Characters [and other sentient creatures] on a plane with subjective directional gravity can move normally along a solid surface by imagining “down” near their feet. If suspended in midair, a character “flies” by merely choosing a “down” direction and “falling” that way.

When specifically on the Elemental Plane of Air, as you specify, we have to consider the following addition to the rules of subjective directional gravity, cited in the planar traits section:

Subjective Directional Gravity: Inhabitants of the plane determine their own “down” direction. Objects not under the motive force of others do not move.

Now that we know how gravity affects objects on the plane of Air, we can address your questions.

For the first and second question:
Objects do not move unless they are attended. If they are attended they will move towards the "down" position of the attender.

For the third question:
To determine who is attending an object, we look to the rules on damaging objects, and specifically on saving throws for objects:

... An item attended by a character (being grasped, touched, or worn) makes saving throws as the character (that is, using the character’s saving throw bonus).

Large vehicles are slightly more complex than simple objects, however, so a quick visit to the rules concerning vehicles is in order. There we can find that a vehicle is only controlled if it has a driver:

A vehicle is a special movable object that requires two things to keep it moving—a driver and a method of propulsion. A driver is a creature with an Intelligence score of 3 or more who is physically able to use the vehicle’s driving mechanism.... Without a driver, a vehicle will not move or will continue moving in a straight line, depending on the vehicle’s state when it becomes driverless. A creature must be the size of a vehicle or smaller in order to drive it.

So, the rules indicate that only the driver can navigate the vehicle, and even take into account "weird currents":

Navigating currents of magical energy, burning magma, or the murky rivers of the Shadow Plane could use a number of skills, but likely use skills similar to those needed to operate water-current and air-current vehicles. Weird-current vehicles always have their driving check DCs increased by 10, and sometimes by 15 in more exotic locales and conditions.

This aligns with the DC15 Wisdom check to change a person's "down" position when in subjective directional gravity. Extrapolating from that:

Only the driver would be able to navigate a ship in the Elemental Plane of Air, and does so by changing their position of "down" to move the ship forward (toward that "down").

• @HeyICanChan excellent point; I've since found the rules concerning vehicles and updated the answer accordingly. Commented Apr 27, 2018 at 15:46