Flying into a Wall of Force effects?

[Lord Thurham]

One of my players has found a rather useful approach for dealing with flying creatures. He’ll ready an action to cast Wall of Force in front of the flying creature. Since the wall is invisible, the creature flies right into it and then….


This is where it gets sticky, I don’t know how to address the effects of a flying creature running into a stationary invisible wall. One could argue that it is like falling damage. So, if the creature is flying at 150’, it would take 15d6 damage??? Or if it is flying at 30’, it would take 3d6 damage? Seems a bit much to me. More to add onto this, the player wants some sort of a roll to find out if the creature can continue flying after the shock of running into a wall. He feels that the flying creature would fall to the ground unless it is able to regain it’s flight mode. Seems like a reasonable request, but all of a sudden, the Wall of Force is a bit powerful in this type of a use. Very creative, but how does the math work on it? Oh and one more thing, can Blindsight see the Wall of Force?

I’ve browsed through the PH and DMG to no avail of a ready answer, so, I bring this question to the collective minds of EN World in the search of a happy solution. Let me know what you guys and gals think of this? Thanks!

LT

 

[Dr_Rictus]

Your analogy to falling damage is very, very flawed. At the end of a 150 foot fall, which only takes about 3 seconds, you are going about 100 feet per second. That's nothing like going 150 feet over the course of a 6-second period of time. The speeds that most creatures can achieve while moving are more analogous to the speed at the end of a 10-foot fall, at most. They are, in other words, pretty negligible for damage purposes.

As to whether the creature can continue flying, that's determined by its maneuverability rating. If it can't turn in place, it obviously cannot recover from being stopped abruptly. If it can, then why should it have any more trouble than after any other surprising event? It's not like flying requires Concentration checks or anything.

 

[Shalewind]

Good question. I had one of my favorite sorcerers about to be gulped by this huge diving dragon. The nasty had begun his dive from (DM said) about 400 ft in order to add to my terror. So I readied an action to cast a wall of force in front of me right before he got there. The DM didn't know what to do.

The dragon went SPLAT. And rightly so. (he wasn't that smart any way). The damage curve for falling in DnD is light (this IS Fantasy). However, flying straight into an object is MUCH different from a dive.

Just cruising at 150' per 15 seconds (10 ft/s) is a constant speed. Assuming the falling damage is based on the velocity of the impact:

10ft - Fall of 0.8 seconds - velocity 16.0 MPH - 1d6 damage
20 ft - Fall of 1.15 seconds - velocity 25.0 MPH - 2d6 damage
30 ft - Fall of 1.4 seconds - velocity 31 MPH - 3d6 damage

cruising at 10 ft/s is about 7 MPH. If you use the falling damage to determine impact... I'd say 1d4 and loss of flight.

Then again. Real physics has no place in DnD.

 

[LokiDR]

I agree with Dr. Rictus. Physics doesn't have any place in D&D, as Shalewind said. I don't know what rules you should use, but here are a few ideas.

Damage for the creature might be 1d6/30' intended movement. A lot less than falling, but linear with speed as falling. Adjust to tast.

Then the question of what happens after the crash. You could give the creature a fort save, DC of the spell, or be stunned for a round. Optionally, this effect could only come into effect if the creature is moving faster than 50' in that round. Or it could be a fort save, DC 1/10th intended move, since the spell DC doesn't make much sense. The save could be will if you think of it as regaining your wits, or ref if you think of "regaining balance". I would go with fort to match the "stunning attack" monk ability. If the creature is high enough to not hit the ground in a round (is it 1600 feet for 6 seconds?), it can regain flight as if it had been diving.

I do think there should be damage based on speed, and some sort of check after hitting the wall or you fall some amount.

 

[magnas_veritas]

Good question. I had one of my favorite sorcerers about to be gulped by this huge diving dragon. The nasty had begun his dive from (DM said) about 400 ft in order to add to my terror. So I readied an action to cast a wall of force in front of me right before he got there. The DM didn't know what to do.

(cut)

Then again. Real physics has no place in DnD.

Well, the rough translation is speed/10=mph...so the dragon hit the wall of force at 40 mph or so, same as if a character on a 3x5 magic carpet hit one at a double move. That would *hurt*.

I just have no idea how much damage it'd do, if any. Well, let's see...time to break out d20 Modern (sigh).

Okay, they have vehicle collision rules. Oh, that's just mean. (Note: Reference is d20 Modern, p. 156 and p. 160)

Roughly...they divide speed into five levels: Stationary (0), Alley Speed (1-20), Highway speed (21-50), and All-out (51+). The number indicates the number of 5-foot squares the entity is moving. So, that diving dragon is moving around 400 feet, or 80 squares, so it's going all-out.

Damage dice are decided on the highest speed of the creatures, and all-out is d12s. The number of dice is decided based on the smallest object involved. Let's say Huge, based on the dragon, since a wall of force can get pretty big. That'd be 12 dice.

So, the dragon would take 12d12, and quite possibly should have some cartoon physics involved (i.e. slide down the wall of force slowly for the rest of the round). I'm not sure if DR would apply; I don't think it would, but that's just me. A quick FAQ check didn't show anything, though inertial barrier suggests that falling damage isn't normally stopped by DR.

Brad

 

[Shalewind]

Well, the rough translation is speed/10=mph...so the dragon hit the wall of force at 40 mph or so, same as if a character on a 3x5 magic carpet hit one at a double move. That would *hurt*.

CUT

So, the dragon would take 12d12, and quite possibly should have some cartoon physics involved (i.e. slide down the wall of force slowly for the rest of the round). I'm not sure if DR would apply; I don't think it would, but that's just me. A quick FAQ check didn't show anything, though inertial barrier suggests that falling damage isn't normally stopped by DR.

Brad

Not bad. Yep. That dragon HURT though. The fighter came to rescue me a few seconds later. Sorry you had to bust out the d20 Modern book. I wouldn't ask anyone to go that far.

 

[Destil]

DMG 69 has the rules for creatures who do not mantain their minimum forward speed to mantain flight. Creaturs fall 150' in the first round, and in the second must make a DC 20 reflex save to recover from the stall of fall a further 300 feet. Every round after that is treated like the 2nd round.

By the rules a creature with blindsight should see an wall of force (Since a wall of force is described as invisible and invisibility is negated through blindsight per the rules).

Though as a DM I think I would rule that a wall of force is not a physical wall at all, but rather a force effect that resists movement, so I don't see there as being anything there to 'see'.

 

[Sixchan]

Another thing to consider is the manner in which the victim is flying. A creature flying vertically won't be so badly hurt. A creature that hits a wall HEAD FIRST will take a LOT of damage. Probably.

 

[Locpik]

By the rules a creature with blindsight should see an wall of force (Since a wall of force is described as invisible and invisibility is negated through blindsight per the rules).

so would a person with "see invisibility" see the wall? I would think ot would fall more under detect magic, the wall is not really there, it is a magic force.

 

[Otterscrubber]

Your analogy to falling damage is very, very flawed. At the end of a 150 foot fall, which only takes about 3 seconds, you are going about 100 feet per second. That's nothing like going 150 feet over the course of a 6-second period of time. The speeds that most creatures can achieve while moving are more analogous to the speed at the end of a 10-foot fall, at most. They are, in other words, pretty negligible for damage purposes.

Actually I've seen plenty of people walk into a glass door and get a nice bump so I imagine that a creature moving faster than a man sprinting and slamming into a wall of force would be signifigant, not negligible. Especiall if it was a big creature with a lot of mass.

And in fact there are rules for creatures regaining their strability after losing it while in flight listed in the DMG, I just dont have the page numbers handy at the moment. Pretty sure they are near the descriptions of the different types of maneaverability.