QUOTE (RedeemerofOgar @ Jan 18 2010, 10:36 PM)
Yah, but the two go together. You use both, or neither, because if you aren't using the Hits = Drain, then you use as many hits as you can get.
Which is the way it was done in 4th edition and all previous editions of Shadowrun. You can use as many hits as you can get, without penalty. To comic effect, in some cases (Mana "Darts" that deal L damage but stages up to Deadly every time, for example).
You roll Magic + Spellcasting at a target. The target either has an Object Resistance threshold or rolls the appropriate resistance attribute. Net hits over threshold or the Opposed test deals Force of Spell in Damage + Net Hits in DV. Drain is based on Force (typically Force/2 +/- some numbers, rounding down). You get additional Drain equal to the net hits if and only if you are using the optional rule to pump drain based on the number of hits used.
It has always been Net Hits increased damage of the spell. Read "Damage Value" on page 204 for details. You can find arguments on this forum as to why the increased drain from the net hits is counterintuitive, but hey, whatever rules you want to use in your games.
"Damage Value: The base Damage Value for Combat spells is based on Force, which is chosen by the magician at the time of casting. Any net hits scored on the Spellcasting Test increase the DV by 1 per net hit. Each spell description notes whether damage is Stun (S) or Physical (P)."