Magic Immunity

[Kaelik]

Where did this 'orbs are creations thus enter into an AMF' come from? Is there any entry on any book who says it or it's just an interpretation for ther non SRiness?

It would be the line in AMF's description that goes:

(The effects of instantaneous conjurations are not affected by an antimagic field because the conjuration itself is no longer in effect, only its result.)

Note the duration of the Orb spells, and their school.