Unbuildable Spell: Floating Disc
I'm proposing this as a Wall spell.
The disc is 3 ft wide, with a 1 inch height, making a concave surface. This is called a 'spherical cap'. The area of a spherical cap simplifies to
pi (a2 + h2)
where a is the 'base' of the cap, and h is the height of the cap. For our disc, that comes out to ~7.09 sq ft. That's...not very different from just a flat circle, but, this is ACKS. I'll be using this value to provide a relative value for the area.
Floating Disc
Wall
| Area: 7 sq ft | 0.035 |
| Duration: 6 turns | 2 |
| Disc expires if forced >10' away | 0.5 |
| Impermeable to creatures | 25 |
| Range: 10' | .5 (edit, rounding via Ary's post makes no change in ttl) |
| TTL | 0.3 |
The area is the cost of 7/100ths of a 100' sq ft wall. The range is calculated from the difference in 0' and 30' range in Wall. The 'Disc Expires' multiplier is stolen from Illusion "Effect expires if creature moves - 0.5x".
This doesn't explain anything else about the disc, however - how it carries things, how it's mobile.
After a bit of consultation with L&E, I find that a 2HD spider or beetle could be postulated that can carry 500 lbs (50 stone) at a BME of 1.68/1.62 and a CCF of .426 or .43. Let's assume we've got a spider-shaped 'Unseen Servant' that carries that disc around?
Summon
| Summon a Creature | 65 |
| Duration: Until task complete (carry the disc) | 2 |
| Limited to the creature type that carries discs | .7 |
| 2HD | .25 |
| Range: 10' | 1 |
| Creature is limited to behavior expected of Floating Disc | .4 |
| TTL | 9.1 |
The duration is until the task is complete (the disc is carried until it pops), and the creature has essentially no interactive parts - it carries the disc the way it carries the disc, cannot be ordered, cannot attack, etc, etc. This is, obviously, the cheesiest of my choices, and I made this as high as possible and as limited as probable without writing a contract.
It does, however, open up the possibility of higher-level discs, so.
This makes for a total of 9.4, rounded to 9.