Spellcasting across mana boundaries

[arnej]

So Magey Mageguy is standing in a normal mana zone, and casts his Sleep spell across the room on Bobby the Barbarian.

Halfway across the room, the mana level drops to Low. Bobby is in the Low mana zone.

Magey made his adjusted roll by X.

Does Bob have to make his HT resist roll by X? Or, since magic in general is weaker where he is standing, does he resist vs X-5?

[Anaraxes]

The 3e answer was that you take the lowest mana zone between subject and caster. 4e Magic didn't change much.

Originally Posted by Roleplayer 20

A missile spell would continue across the boundary into a no-mana zone. No other spell or spell effect would cross into a no-mana zone.

When a spell is cast between different zones, both of which contain mana, calculate penalties as for the lower of the two zones. Thus, if either the caster or the subject is in a low-mana zone, the roll will be at -5. In the case of a spell like Great Voice, in which the "target" of the spell is the speaker, the location of the listener(s) doesn't affect the spell, as long as they are not in a no-mana zone.

A caster in a zone of very high mana has the benefit of fatigue-free casting (if he's a mage) and the problem that any failure will be very dangerous, regardless of where his subject is standing.

http://www.sjgames.com/gurps/Rolepla...#anchor1158242

Note that you can choose a non-straight-line path for your spell to take (Word of Kromm), assuming you're willing to soak the additional range penalties. Spells don't have to follow minimum-distance straight lines. This is perhaps most important when someone wants to hide behind a small no-mana zone. They're not completely safe unless they're completely surrounded.

[arnej]

Originally Posted by Anaraxes

The 3e answer was that you take the lowest mana zone between subject and caster. 4e Magic didn't change much.

Awesome, that's what I needed. Thanks!

[Plane]

Originally Posted by Anaraxes

The 3e answer was that you take the lowest mana zone between subject and caster.

Re http://www.sjgames.com/gurps/Rolepla...#anchor1164591 it mentions:

if either the caster or the subject is in a low-mana zone

I'm not sure it addresses the idea of what if both caster/subject were in normal-mana zones but there was a low-mana zone somewhere between the straight line.

Originally Posted by Anaraxes

you can choose a non-straight-line path for your spell to take (Word of Kromm), assuming you're willing to soak the additional range penalties

Immediately before the WOK it says missile spells have to go in straight lines though...

Q: Can you curve a missile spell around a NMZ? What is the penalty for aiming missile spells in this manner?

Missile spells always travel in straight lines. You cannot curve them to travel around NMZs.

Q: If magic cannot traverse areas without mana, does this apply even if the spell could travel around the no-mana zone? As apart from either caster or target being surrounded by the NMZ?

A spell always travels from caster to subject via the shortest route that contains mana. If any of that route is in a low mana area, there is a -5 to skill; if there are two routes and only one crosses low mana, the one with the lowest total skill penalty (for distance & mana) will be taken. Distance penalties (regular or long-distance) are figured based on the actual path taken, not the straight-line distance from caster to subject. This means that a caster can affect a subject who is separated from her by a no mana zone (NMZ), provided her skill is high enough to absorb the penalties for casting around it.

Does this mean we need to invent some kind of modifier for missiles spells to allow them to curve around corners or no/low mana zones?

[PTTG]

This is going to need the GM to describe their magic system. Is a fireball spell a mundane ball of fire and fuel conjured by the wizard? Then only the location of the wizard matters. Is it a spirit of fire that flies directly at the target, then "plays" with them via combustion? Then it could get blocked or weakened by even a small are of low mana in-between.

If all the wizard is doing is supplicating the innate ignus energy of the world around the target to mainfest, then the wizard might even be able to do so while standing in a null-mana zone, so long as his words can reach the right spot.

[Not another shrubbery]

Originally Posted by arnej

So Magey Mageguy is standing in a normal mana zone, and casts his Sleep spell across the room on Bobby the Barbarian.

Halfway across the room, the mana level drops to Low. Bobby is in the Low mana zone.

Magey made his adjusted roll by X.

Does Bob have to make his HT resist roll by X? Or, since magic in general is weaker where he is standing, does he resist vs X-5?

Regarding resistance - The effect of Low Mana is on the spellcaster's success roll, so Magey would have had a -5 penalty on his skill level with Sleep for targeting Bob in an LMZ. Assuming that is factored into Magey's adjusted roll, Bobby will have to make his resistance roll by X.