Non-Binary Gravity

In arcane space gravity is either binary (flat, 2-sided) or spherical (attractive in all directions). Unfortunately, there are many exceptions to this, such as the Scorpion ship (which has a gravity plane that actually curves along the tail and makes a 180 degree turn), some of the artificial objects in RealmSpace (like the wizard's tower and the mind flayer "beehive"), and the ships of the tripartite creatures. Being bothered by this, I have sat down to do some fiddling with the gravity system.

My original thought was to have different sorts of gravity due to magical spells, but looking at the 7th level spell reverse gravity made me pause - if this simple spell only lasts a short time and has a very specific effect, spells that were long-lasting and general would have to be 9th level or higher! Thus the use of such magics by the Scro for their ships would be almost impossible.

Trying to circumvent this problem, I noticed something. All forms of gravity that we know of (in real space or arcane space) are attractive. The reverse gravity spell makes gravity act in a repulsive fashion. This must be contrary to the basic laws of the universe, thus the high level of the spell. Spells which alter the direction of gravity but still allow it to remain an attractive force should be much simpler.

I therefore came up with the following theory and a new set of spells affecting gravity. All three spells can be made permanent with the permanency spell (XP cost = 500 x spell level).

Theory of Nonbinary Gravity
There is a very brief state in which the gravity of objects is neither binary (with down on both sides of an object) nor spherical (like a planet): a disclike state that begins to bulge out into a double-saucerlike state, and finally to spherical. However, the difference between a binary-gravity state and a spherical-gravity state is probably only on the order of a few hundred pounds of material (i.e., very minor, cosmically speaking). Essentially gravity is an either-or situation (like quantum mechanics' wave-or-particle theory) and natural situations that fit neither state are going to be so rare as to be practically nonexistant. Magic can alter the effects of gravity, of course.

Lesser Gravity Alteration
Transmutation
Level: Sor/Wiz 3
Components: V, S, M
Casting Time: 1 action
Range: Medium (100 ft. + 10 ft./level)
Area: Two 10 ft. by 10 ft. cubes per level (S)
Duration: 1 minute/level
Saving Throw: None
Spell Resistance: No

You turn the directive force of gravity from its normal orientation, allowing sloping or vertical walls to be traversed by normal walking rather than climbing. Gravity orients to point "down" to the closest physical surface, although the spell cannot cause gravity to change more than 90 degrees from normal (limiting its use to sloping and vertical surfaces but not allowing walking on ceilings, for example). In places where surfaces meet at an angle (such as a floor and a wall), the gravity changes to a 45-degree angle relative to the two surfaces for a 5-foot span on each surface, allowing creatures to walk from one to the other. Entering an area of different gravity requries a Balance check (DC 10 for a 45-degree angle, 20 for a 90-degree angle) to remain standing.
   Creatures taller than the height of the area of altered gravity who try to move must make Balance checks (DC 5) each round or only be able to move half speed that round. Flying creatures that pass through the area of altered gravity must make Balance checks (DC 5) or lose 5 feet of flying movement that round.
   Normally this spell is made permanent and used to make a gravity transition on a spelljamming ship smooth, allowing more of the ship's surface to be used. For example, a ship with a forecastle might have this spell on one wall of the forecastle, allowing the crew to walk on the side of it as if it were a floor, freeing up space elsewhere in the ship. It can also be used to allow multiple creatures to walk up a wall, down a cliff face, and so on.
    The spell does not penetrate the surface it is cast upon. This means that while one side of a wall may be affected by this spell, the other side acts like a normal wall (creatures are not pulled toward it as if it were a floor).
    Material Component: A paste made of iron filings, diamond dust, and grav blood worth 50 gp.

Greater Gravity Alteration
Transmutation
Level: Sor/Wiz 5

As lesser gravity alteration, except as noted above and that it can even alter gravity greater than 90 degrees from normal, allowing walking on ceilings.

Gravity Shunt
Transmutation
Level: Sor/Wiz 7
Components: V, S, M
Casting Time: 1 action
Range: Medium (100 ft. + 10 ft./level)
Area: One 10 ft. cube per level (S)
Duration: 1 minute/level
Saving Throw: None
Spell Resistance: No

You cause the fundamental gravitational force of matter to align itself against itself, resulting in an area of no gravity (in other words, every other square inch of the area of effect aligns its gravity one way, while the remaining spaces align their gravity in the opposite direction, canceling each other out). This effect is similar to being next to a crystal shell or a starbeast -- there is no pull towards that object. Without gravity, creatures can easily push themselves off of the surface, although without the ability to fly moving in the air is difficult (as a full-round action, a character can "swim" in the air, moving a number of feet equal to a Strength check minus 10, or half that with a move-equivalent action*).
Material Component: A paste made of iron filings, diamond dust, and grav blood worth 50 gp.

*If Andy Collins already covered moving in zero-gravity in his Shadows of the Spider Moon spelljammer campaign setting he wrote for Polyhedron, ignore this improvised rule and use that instead.