Hi there!
I've a pair of questions about the spell Telekinesis:
1) If I lift an object in the air and then I drop it on some enemies, how can I calculate the damages?
I can't find nothing on manuals about damage from falling objects. I believe that using just the falling damage (1d6 / 10 feet) is not enough.
2) In the case that I hurl the object directly against an enemy, how should I calculate the damages?
I think that this could be similar to the spell Catapult (from "Elemental Evil Player's Companion"), but I can't figure how much damage could inflict a 1000lb object, in comparision with a 5lb object suggested from that spell.
Thank you
1: You falling 10' onto the ground is physically identical to having the planet fall 10' on you. So 1d6/10' works just fine.
2: Figure out how much damage a 1000lb object would deal if someone gently placed it on you. Then add 1d6/10' that.
I'd also be very, very cautious about designing these rules on your own.
3e, for instance, tried this with Complete Warrior's improvised weapon rules based on weight, which makes perfect sense for improvised weapons in a bar fight or what happens when an ogre tips a wagon over on you. Those are the same rules that broke a quadrillion d6 damage with the Hulking Hurler.
mellored wrote:
Hamsterkill wrote:
mellored wrote:
Hamsterkill wrote:
mellored wrote:
I'd also go by 1d6 damage per 10ft rule for any heavier object that actually can hurt (not a feather), simply out of the reason that it will do similar damage than if you lifted the creature itself with the spell and anything else would probably be unbalanced.
Alternatively: Make the creature do a strength saving throw with DC depending on the weight of falling object and adjust damage depending on how badly the character failed.
kinetic energy (damage) = mv²
figure it out 
If you really think it's important...suggestion?
Base = 1d6 per 10ft fallen. Slide decimal place left, add "d6."
+1d6 per 100lbs (100=+1d6, 200=+2d6, etc). So take the weight of the thing, slide the decimal place left twice, slap "d6" at the end. Do nothing if less than 100lb. Add result to the above value.
(If object is over 100lbs and falls less than 10ft, still add d6's this way.)
So, say you have a 100lb weight falling 100ft.
100ft / 10 = 10d6 dmg
100lb / 100 = 1d6 extra
10 + 1 = 11d6 dmg
Average 39 dmg, or slightly more lethal than skydiving 100ft. Drop a grizzly bear on someone, you're looking at 20d6 or so. Definitely lethal to a lvl1, eventually survivable. Fall damage is already wacky, but at least you've accounted for weight, if you thought it was important. If you're looking at weaponized telekinesis and such, just the base falling rules seem fine for balancing purposes. If dropping rocks on people always does scads more damage than any other option, you'll just see players tripping over themselves to throw rocks at every baddie they see.
Thank you for your answers!
mellored wrote:
Given that the object is moving at walking pace, cannot control its descent, and only attacks from directly above, a dex saving throw for no damage is probably fair.
I'm not sure what system I'd use to hit. Either some sort of Intelligence check to try to work out from the angles whether the object is actually directly above the target or not. Or just treat it as a 5ft vertical cylinder AoE attack, but that doesn't really represent the realism of physics that you are trying to introduce.
To be frank, best bet might just be to look at the damage of boulders thrown by Giants, and knock an bit off the to hit and damage due to not being able to aim, and the fact that they are just being dropped, not thrown.