I ruled that teleportation spells cannot take you into a regio. This was maunly to keep them hard to get into, but is also arguably RAW as the rules on regios list only a few specific ways to get in, and teleporyation isn't one of them.
What about Intellego spells? Spells to summon stuff from a regio? What about shoofing a pilum of fire into a regio?
I suggest to keep regios as a different "level" of reality, much like a Realm of power. So you basically can't affect it with magic without goong into it, although Intellego Vim can be used to see through the veil. And excepting Mysteries (Hermetic Theurgy can summon stuff from a regio, Arcadian Yravel lets you teleport to one, and so on). But I'm not sure that's the right approach.
I can't remember which books its in, but it is stated that some regiones can be crossed with teleportation, and others can't.[/quote]
It's in AtD, prior to which there were no official rulings on the subject at all.
Similarly, we know there are spells to see across a region boundary (Pt*V) but can you use eg. Summoning the Distant Image across a regio boundary?
AFAIK, there's nothing official about this, and much as the AtD ruling (on teleportation) makes me twitchy, I'd go with the same answer in this case.
It would seem to me that unless you a) have an arcane connection, b) are casting literally through the entryway or c) are casting an InVi spell designed to deal with region that the 4 dimensional aspect of regios is a bit beyond Medieval mathematics, and casting would be impossible.
I'm not entirely sure what you're saying here. You used or in the sentence of your options. So, if I have an AC, I can cross the regio boundary with teleportation? If I can see to the other side, I can use a spell like Wizard's Leap?
The general question is for all spells, but yes, if you have an arcane connection to a region you should be able to use that to teleport in. Unless of course the region has special rules to prevent that...
In order to keep regios at least somewhat of a challenge, I still like to require the first crossing to be performed "manually" and then subsequent crossings can be done magically. If you have an AC to a regio you have never actually visited and attempt to Leap into the regio, well, interesting things can happen...
I think you should not try to make consistency with regios, they should be a mystery that remains a riddle across the Order. Some have predictable means of ingress and egress, many don't, and no one really knows why.
IMO the only way one should be able to get consistent results with the majority of Regios would be through a breakthrough of some kind and/or a Mystery power. To a degree this is already the case, both Criamon and Merinita have powers that allow some travel through Regios. Making normal Hermetic spells that allow one to travel easily through regios or that even cross the regios basically takes away the power of those hard earned Mysteries.
Keep them vague that way they can be used as a plot device for the SG and a boon for the Covenant and certain players.
I think Regios can do whatever they want. IF it is a regio that can be crossed by spells, then I would say you need to see inside the regio somehow, or have an arcane connection and then use the appropriate spells. I wouldn't allow the spells that go a specific number of paces to get you anywhere flying, burrowing wouldn't. Generally.