[zylosan]

There is a mention in SR4A Area Spells pg. 173 "Dice expended to change the radius of effect cannot be used in related tests, such as resisting Drain for that spell". 

So is it still possible to under SR4A RAW to take a dice penalty to your spell casting check to gain additional dice on your drain reistance check? Cause its not mentioned in the rules for spell casting.

A related question is about foci. Which indicate that the bonus dice from from the foci can be withheld to help resist drain. Is this just a special aspect of the foci?

[Charlie Green]

No.
You can get exstra dice from centering and centering foci.
 

[Lethe]

The radius one is a copy paste mistake.
The focus reference i can't find anywhere.

But yeah, no, its not possible.

[Henzington]

only sure way to lower drain is to cast the spell at a lower force

[Orvich]

I'm going to check SR4A but I know that in plain SR4, you can use ONLY spellcasting foci like this. During any given casting you can either use the focus for the spellcasting roll or the drain resist roll.

Looks like they changed it in SR4A, but the relevant text in the old core is:

Spellcasting  foci add their Force to a magician’s Spellcasting and Ritual Spellcasting dice pools. These dice may be used to cast a spell more effectively or withheld to help the magician with Drain.

[Thrass]

All I can find in SR4A is:

Ritual Drain
At the end of the ritual, each member of the ritual team—including
the spotter—must resist the Drain of the spell. Individual magicians
with foci or bound spirits not otherwise occupied may use them to
help with Drain.

I didn't check SM though

[Crash_00]

I haven't found any reference in SR4A to being able to use Spellcasting Foci to aid with drain rolls. I don't see it being overpowering at all, and I don't know if the change was intended or not, but it isn't listed in the changes document at all, so it's kind of up in the air.

[Zilfer]

Yeah i've been kind of curious myself with that change. I started playing thinking it did work that way and then found out it didn't.

[Thrass]

at least there are centering foci in SM

[Valnar]

Still, the idea of subtracting some of your spellcasting dice to increase your drain pool was pretty rad. I'd really like to know why the people responsible for the SR4A magic rules felt that it had to be removed.
Another strange magic rule one of our players noticed:

The caster can reduce the time required for a spell to become permanent
by sacrificing net hits from the Spellcasting Test; every 1
net hit spent this way reduces the sustaining period by 1
Combat Turn. Hits used this way do not increase the effect
of the spell.

Source: Street Magic page 161

Is there any reason to ever do this, instead of just casting the spell at a lower force? Because, you know, casting it at lower force will reduce the sustaining period just as well, but you'll have to resist less drain and can cast less noticeable spells.

[UmaroVI]

Witholding dice from the test to resist drain was a thing in previous editions. References to that rule got copypasta'd in due to terrible editing, but it's not a thing anymore.

Valnar: Heal is the only spell it's useful on (because the drain caused by Heal is not Force-dependant). Otherwise, no, it's pointless and has no reason to exist.

[Tagz]

It was likely a balance issue that it was taken out.  Many spells only require a single success to be effective.

Take for instance a Control Thoughts spell.  Force only caps the hits and effects how long it takes for the victim to get a chance to shake it off.  Opposing that is the victim's Willpower (+Counterspelling), typically this isn't going to measure up too great against a good mage's Spellcasting + Magic (+Foci).

The real limiting factor that will keep a mage from using this for everything is going to be the Drain, that and possibly a mad GM.  If you could take some of those dice you likely wouldn't need anyhow and then put them into Drain Resistance tests, it would make it much more efficient.

After all, on average it's 3 dice to a hit, an opponent without Counterspelling would likely only have a dice pool between 2-6.  That means on average the defender is only going to get 1-2 hits on resistance.  A mage with 12 dice doesn't really need to worry about beating (on average) the target.  If they have anything more then 10 they could safely have just applied it towards Drain Resistance, and with Foci added in it's not that hard to get pools around 18-20 dice.

I like the old rule in terms of style and theme.  But when it comes to spells that don't require high Force, don't need too many hits, and can have dramatic results...  I think that balance wise it makes more sense to not allow it.  A real shame because as a theme I love it.

[Qemuel]

There is a quick mention about this in the FAQ.  Here is the quote for reference:

In SR4, can you withhold dice from a Sorcery or Spellcasting Test and use those dice instead to resist Drain, as you could in SR3?

This rule was dropped in SR4—it was a special case rule that didn’t apply to any other mechanics in the game. If you happen to like it, you can of course continue to use it in your own games as a house rule. The entry for the Spellcasting Focus in SR4 had an incorrect reference to this rule that was corrected in SR4A.

So it's no longer official, but can easily be houseruled.  Bottom line is that it is up to the GM.  It doesn't seem to break anything, but since SR4 tried to streamline and correlate rules, they took it out.