Egres said:
Ok,this is the situation.
If an Arcane Archer fires an arrow imbued with a Fireball spell,and he misses his target,how can we establish where the arrow will land in order to know the Fireball area of effect on the grid?
Thank you in advance!
Well... I don't know if the rule survived in the 3.5 DMG, but one of my favorite optional rules from the 3.0 DMG deals with missed ranged attacks (arrows, rays and so on). The rule is very complicated, but I like to us it because players should beware where they are pointing their missile weapons and spells. OK, here goes:
PC rolls attack roll as normal.
First you check if the arrow connected, that is, if it was good enough to hit if it had been a ranged touch attack. If that is the case, the arrow hits it's target, but just didn't penetrate the armor. In your case, the fireball would be exactly where your AA wanted it.
If it didn't connect, the projectile is considered "errant."
First of all, you now need to learn the path of the errant projectile. This depends on whether is was a direct fire shot or an indirect fire shot.
If the target was further away than the listed distance, the attack is indirect fire, if it as far or closer than the listed distance, the attack is direct fire:
MAXIMUM DIRECT FIRE RANGE:
Ray: Infinite
Heavy crossbow: 250'
Light crossbow: 200'
Hand crossbow: 120'
Long composite bow: 120'
Longbow: 100'
Short composite bow: 80'
Shortbow: 60'
Sling: 50'
Any thrown weapon: 20'
Now, if the fire is DIRECT, we determine it's deviation:
1d20:
1-8: Left deviation
9-16: Right
17-19: Long
20: Short
1d20: (round to nearest square)
1-12: 1/10th of range to target
13-17: 1/5th of range to target
18-19: 1/3rd of range to target
20: Half of the range to target
Now we know where the errant projectile is headed (note it might still hit in the square where the target is, it just doesn't hit the target), and now you trace the path of the arrow. If there are any characters in the path, you start with the one nearest the attacker and check whether or not the projectile connected with that character. You do this by rolling a ranged touch attack roll as normal, but you discount the skill of the attacker (but leave in magical adjustment and modifications for cover). If it connected the projectile stops in this square, and if the attack roll would even defeat the AC of the unlucky character in the projectiles path, you roll for damage. If the touch attack doesn't connect, you roll a ranged attack roll for the next character in the line of fire and so on until the projectile hits the ground in the square indicated by the deviation rolls above. (Or a wall or similar)
If the fire is INDIRECT it is a little easier. The deviation for indirect fire is:
1d20:
1-4: Left
5-8: Right
9-14: Long
15-20: Short
1d20:
1-12: 1/10th the range of the target
13-17: 1/5th
18-19: 1/3rd
20: 1/2
When the deviation has been found, you know which square the projectile landed in. If there is a character in that square you roll a ranged touch attack as above (without taking into account the skill of the attacker, only magical bonusses and modifications for cover). If succesful, it connects with the target, and if the attack roll beats the AC it does damage. If the ranged touch attack fails the projectile hits the ground in the square and stops.
Not very streamlined but those are the official 3.0 rules (I haven't bought the 3.5 DMG yet), and of course they are only really relevant in cases such as your own or in cases where someone callously fires projectiles or rays at a target in the middle of a crowd or engaged in melee or something...
I hope it will help you...