Line of Sight and opennings. [Archive] - Wizards Community

Line of Sight and opennings. [Archive] - Wizards Community

Post/Author/DateTime Post
HIDragonstar
03-05-07, 12:02 AM How big of an opening would someone have to consider to cast either Magic Missile or Fireball?

I have a player who is a wizard and says he can throw fireballs through keyholes. The Player's Handbook says that the fireball is a 'pea-sized' and he is "Right Up" at the keyhole he should be able to cast fireballs through the keyhole, as well as Magic Missiles. I know for the fireball you had to 'roll a to hit', but the magic missles it says always hits.

Players knock at the door. Bouncer opens the window at the eye level of the door to see who it is. Magic Missiles fly through the keyhole. Take down the bouncer. Next round... fireball flies through the keyhole and wipes the room.
StoneStokes
03-05-07, 02:07 AM ...
I have a player who is a wizard and says he can throw fireballs through keyholes. The Player's Handbook says that the fireball is a 'pea-sized' and he is "Right Up" at the keyhole he should be able to cast fireballs through the keyhole, as well as Magic Missiles. I know for the fireball you had to 'roll a to hit', but the magic missles it says always hits.

If you don't want to allow this there is a simple solution: "keyholes in this world are not the see-all-the-way-through variety as seen in cartoons; they resemble modern keyholes with lots of mechanics in the way."

Players knock at the door. Bouncer opens the window at the eye level of the door to see who it is. Magic Missiles fly through the keyhole. Take down the bouncer. Next round... fireball flies through the keyhole and wipes the room.

I would be inclined to let the magic missiles hit so long as the spellcaster can see the target, and has a clear line of effect. On the other hand, fireballs have a chance of missing the opening. This would be very bad news for the PCs!

If you are playing in a low fantasy setting, even ordinary glass in the peep hole makes the plan a bit harder to execute. In a high fantasy setting, if the peep hole is at the door to a powerful secret society, consider replacing ordinary glass with something like a well-cut diamond (this will be very hard to break, but still allows the bouncer to see out...in fact, you could make it one-way optics as well).
Merestil Haye
03-05-07, 12:58 PM Line of Sight is simple. If you can see something directly, you have line of sight to it. But that's not the only thing you need to worry about. You also need to consider line of effect, And it is line of effect that decides whether you can shoot a spell through an obstruction.Line of Effect

A line of effect is a straight, unblocked path that indicates what a spell can affect. A line of effect is canceled by a solid barrier. It’s like line of sight for ranged weapons, except that it’s not blocked by fog, darkness, and other factors that limit normal sight.

You must have a clear line of effect to any target that you cast a spell on or to any space in which you wish to create an effect. You must have a clear line of effect to the point of origin of any spell you cast.

A burst, cone, cylinder, or emanation spell affects only an area, creatures, or objects to which it has line of effect from its origin (a spherical burst’s center point, a cone-shaped burst’s starting point, a cylinder’s circle, or an emanation’s point of origin).

An otherwise solid barrier with a hole of at least 1 square foot through it does not block a spell’s line of effect. Such an opening means that the 5-foot length of wall containing the hole is no longer considered a barrier for purposes of a spell’s line of effect.The key is this. If the door or wall has a hole in it with an area of less than 1 square foot, you cannot cast the spell on the target or affect that area. Is the keyhole an area of 1 square foot or larger? That's the only question to answer.
Millennium
03-05-07, 01:26 PM Line of Sight is simple. If you can see something directly, you have line of sight to it. But that's not the only thing you need to worry about. You also need to consider line of effect, And it is line of effect that decides whether you can shoot a spell through an obstruction.
This is important to keep in mind: line of sight and line of effect are two different things. Sometimes -often, even- they coincide, but sometimes they don't. To give two examples, fog blocks line of sight but not line of effect, while the surface of a body of water blocks line of effect but not line of sight.
Nom
03-05-07, 07:43 PM Beyond Merestil's answer, there are special rules for fireball (only) that allow you to shoot throw a smaller-than-normal space. I don't think I'd let you fireball through a keyhole, though; the pea wouldn't fit without touching the sides (Boom!). A small window, yes.
Dragonteuthis
03-06-07, 07:04 PM Pretty unrelated, but I just had an idea for peepholes: No holes in the door at all, but instead a section of door that's been enchanted to let the occupants see through the door (yet still opaque from outside).

Obviously, not good for operations running on a shoelace. But acceptable for a major theif guild's base, or an arcane lab, etc.

Post/Author/DateTime	Post
HIDragonstar 03-05-07, 12:02 AM	How big of an opening would someone have to consider to cast either Magic Missile or Fireball? I have a player who is a wizard and says he can throw fireballs through keyholes. The Player's Handbook says that the fireball is a 'pea-sized' and he is "Right Up" at the keyhole he should be able to cast fireballs through the keyhole, as well as Magic Missiles. I know for the fireball you had to 'roll a to hit', but the magic missles it says always hits. Players knock at the door. Bouncer opens the window at the eye level of the door to see who it is. Magic Missiles fly through the keyhole. Take down the bouncer. Next round... fireball flies through the keyhole and wipes the room.
StoneStokes 03-05-07, 02:07 AM	... I have a player who is a wizard and says he can throw fireballs through keyholes. The Player's Handbook says that the fireball is a 'pea-sized' and he is "Right Up" at the keyhole he should be able to cast fireballs through the keyhole, as well as Magic Missiles. I know for the fireball you had to 'roll a to hit', but the magic missles it says always hits. If you don't want to allow this there is a simple solution: "keyholes in this world are not the see-all-the-way-through variety as seen in cartoons; they resemble modern keyholes with lots of mechanics in the way." Players knock at the door. Bouncer opens the window at the eye level of the door to see who it is. Magic Missiles fly through the keyhole. Take down the bouncer. Next round... fireball flies through the keyhole and wipes the room. I would be inclined to let the magic missiles hit so long as the spellcaster can see the target, and has a clear line of effect. On the other hand, fireballs have a chance of missing the opening. This would be very bad news for the PCs! If you are playing in a low fantasy setting, even ordinary glass in the peep hole makes the plan a bit harder to execute. In a high fantasy setting, if the peep hole is at the door to a powerful secret society, consider replacing ordinary glass with something like a well-cut diamond (this will be very hard to break, but still allows the bouncer to see out...in fact, you could make it one-way optics as well).
Merestil Haye 03-05-07, 12:58 PM	Line of Sight is simple. If you can see something directly, you have line of sight to it. But that's not the only thing you need to worry about. You also need to consider line of effect, And it is line of effect that decides whether you can shoot a spell through an obstruction.Line of Effect A line of effect is a straight, unblocked path that indicates what a spell can affect. A line of effect is canceled by a solid barrier. It’s like line of sight for ranged weapons, except that it’s not blocked by fog, darkness, and other factors that limit normal sight. You must have a clear line of effect to any target that you cast a spell on or to any space in which you wish to create an effect. You must have a clear line of effect to the point of origin of any spell you cast. A burst, cone, cylinder, or emanation spell affects only an area, creatures, or objects to which it has line of effect from its origin (a spherical burst’s center point, a cone-shaped burst’s starting point, a cylinder’s circle, or an emanation’s point of origin). An otherwise solid barrier with a hole of at least 1 square foot through it does not block a spell’s line of effect. Such an opening means that the 5-foot length of wall containing the hole is no longer considered a barrier for purposes of a spell’s line of effect.The key is this. If the door or wall has a hole in it with an area of less than 1 square foot, you cannot cast the spell on the target or affect that area. Is the keyhole an area of 1 square foot or larger? That's the only question to answer.
Millennium 03-05-07, 01:26 PM	Line of Sight is simple. If you can see something directly, you have line of sight to it. But that's not the only thing you need to worry about. You also need to consider line of effect, And it is line of effect that decides whether you can shoot a spell through an obstruction. This is important to keep in mind: line of sight and line of effect are two different things. Sometimes -often, even- they coincide, but sometimes they don't. To give two examples, fog blocks line of sight but not line of effect, while the surface of a body of water blocks line of effect but not line of sight.
Nom 03-05-07, 07:43 PM	Beyond Merestil's answer, there are special rules for fireball (only) that allow you to shoot throw a smaller-than-normal space. I don't think I'd let you fireball through a keyhole, though; the pea wouldn't fit without touching the sides (Boom!). A small window, yes.
Dragonteuthis 03-06-07, 07:04 PM	Pretty unrelated, but I just had an idea for peepholes: No holes in the door at all, but instead a section of door that's been enchanted to let the occupants see through the door (yet still opaque from outside). Obviously, not good for operations running on a shoelace. But acceptable for a major theif guild's base, or an arcane lab, etc.