3.5 - Concentration and line of effect

[Grand Poobah]

Afternoon Giants,

Looking at the SRD, you need line of effect to a space you create an effect in.


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.

If a spell is cast that is maintained by concentration does the caster need to maintain line of effect after the round in which the spell is cast or effect created? RAW suggests not but I'm going off the SRD as I'm AFB at the moment.

Thanks

[Necrov]

Hmm. I'd like a particular example before I make a hard decision. But RAW says no, as once you are merely maintaining concentration on a spell, the point at which you 'cast' the spell has gone. But depending on abuse, I'm not necessarily sure that this is a precedent I'd want to set. Though, I'm currently struggling to think of anything particularly abusive.

[Grand Poobah]

Hmm. I'd like a particular example before I make a hard decision.

Sure.

Dungeon corridor split by a crevasse 10' wide and 10' deep, at the bottom of which is a gently flowing river which quickly disappears around a bend and out of sight.

I'm being chased by Orcs who are a round or two behind me. I cast a silent image of myself on the opposite side of the crevasse. I have line of effect to the space the image is created in.

I then jump into the river and I'm able to maintain concentration as it isn't flowing that fast and I have a good swim skill. I no longer have line of effect to my image but I make the image move further down the corridor to whatever the 'effect' limit is for the spell.

[Necrov]

Sure.

Dungeon corridor split by a crevasse 10' wide and 10' deep, at the bottom of which is a gently flowing river which quickly disappears around a bend and out of sight.

I'm being chased by Orcs who are a round or two behind me. I cast a silent image of myself on the opposite side of the crevasse. I have line of effect to the space the image is created in.

I then jump into the river and I'm able to maintain concentration as it isn't flowing that fast and I have a good swim skill. I no longer have line of effect to my image but I make the image move further down the corridor to whatever the 'effect' limit is for the spell.

Yep. I like this example. I think it'd be a clever use of the ability and spell. RAW, as we've already established it works fine. I would probably rule that the Silent Image can only interact properly with the environment that you know to be there.

So if unbeknownst to you the corridor ended after 60 feet, and you didn't know this because it was a dark corridor and you could only see 30 feet down it. (Ignore actual distance rules here, it's only an example to make a separate point) After this distance I'd argue that even with concentration the Image isn't going to interact with the environment properly, and may just run 'down the corridor' through the wall and beyond until it reaches the range of it's effect.