I hope there is anyone here who can really answer this question for me. We seem to have some trouble solving this:

My magician has the following interpretation:

You have to be on the same plane as the spells/powers target when it is cast/activated. Afterwards you can change from the Physical World to Astral Space or the other way around or even travel to a metaplane without any problems and the spell/power is still active. My interpretation of the rules is that you not only have to be on the same plane as the target in order to cast a spell or activate a power but you also have to stay on that plane of existance if you want to continue sustaining that power.

Examples:
a) A magician casts Improved Invisiblity on the team's Streetsam and then leaves his body to astrally project and scout ahead. He continues to sustain the spell withouth being in the physical world.

b) A spirit is ordered to use his Concealment power on the Streetsam and then leave the Physical World and hide in Astral Space while sustaining the power. He might even be ordered to return to his metaplane and continue sustaining it.

Is that really possible? It seems somehow strange to me that you have to be on the same plane to cast a spell but could leave it while still sustaining it. I hope someone can help us with that problem!

Thanks a lot!
Matze

I guess you only registered for that one question right?
and damn it, that's a hard one . .
i ain't really sure, but i guess your Mage is right about this.
It would really nerf sustained powers like concealment.
Because if the spirit has to stay in the real world, it has to hide somewhere.
so it can not hover around and guard you on the astral plane.
Or take the metaplane shortcut to help you inside wards.
not without dropping the concealment, which might invoke other problems.

Hi!

You're right, I just registered for that one question (at least for now) but I do read here from time to time. Usually I get all the answers I need on the official German Shadowrun Board at Pegasus, but not this time

The spirit could just conceal itself, it can use Concealment on more than one target after all (up to its force rating if it is not sustaining anything else). And why should a magician be able to take spirits with him through wards if they could just take that quick detour through their metaplane without having to quit sustaining concealment and make the runners more visible? The mage would just walk through and the spirits don't care if there is a ward because they sustain from their metaplane anyway

Somehow I have the distinct feeling that this is a case of pure interpretation and both are correct according to the rules and it is up to the GM in the end. Either you allow sustaining from a different plane or you don't, I can't find a clear statement in the rules for this. At least nothing I would consider to be a clear statement

re: B

Street Magic p. 95

"Since Guard is a physical power, it requires the spirit
to be physical in order to activate it (though not to sustain it).
Therefore, a spirit ordered to use Guard on someone would
need to use Materialize or Possession before it could do so,
and both actions would only require one service (though it
might immediately go back to astral plane while sustaining
the Guard effect, depending on what other services it was performing
at the time)."

This implies A is possible. Also, note that the switching of planes, going astral, is not listed in the Ongoing effects on P. 174 SR4

"If the gamemaster chooses, certain circumstances may
threaten to break a magician’s concentration while she is sustaining
a spell, such as taking damage, full defense, dropping prone,
and so on. If a magician’s concentration is disrupted while sustaining
a spell, she must make a Willpower + Spellcasting (2)
Test to avoid dropping the sustained spell (note that the sustaining
modifi er does not apply to this test)."

Though you always have the option as the GM to have the player make that roll.