QUOTE (Ascalaphus @ May 28 2010, 02:15 PM)
Your interpretation seems sensible, but how do you handle a mage holding his fingers before his eyes to screen out part of the area of effect? I'm having trouble describing why it wouldn't work, but it feels wrong somehow.
I don't have an in-game fluff reason for why it wouldn't work, but I don't like it, and I don't allow it in my games. I'd tell the players before-hand so they're not surprised by what sounds like an arbitrary ruling.
This was originally documented in the SR3 FAQ (http://www.shadowrun4.com/resources/sr3faq.shtml). For your convenience I'll reprint that portion of text below:
[ Spoiler ]
If a magician holds up his hand, or a piece of paper, or whatever, to block a target from his vision, does that mean they're not a "valid target" for an area effect spell? In SR3, do magicians who try to intentionally limit their area effect spells suffer some penalties or chance of spell misfire?
In FanPro's opinion, no GM should allow players to get away with this kind of stunt without penalty. A magician who plays these sorts of mind games with himself is asking for it--any attempt to thwart the intent of a spell simply causes it to fail outright, but the caster gets slammed with the Drain anyway.
If the GM wants to allow players to get away with tricks like this, then apply the cover modifier that the caster wishes to give the excluded target to the TN of the spell. If the caster wants to give the excluded target total cover (anything less and the spell affects them--except in the case of elemental manipulations), then the spell's TN increases by 8 (equivalent to blind fire, a +8 modifier). The magician could, of course, center against this penalty. If the caster wants to pull this stunt with multiple targets, the penalties stack unless the targets are very close together, in the GM's opinion. (Just imagine trying to block two specific people entirely out of your field of vision in a crowd.) If you want to be really cruel, apply the TN modifiers to the spell's Drain Test, too.