Magic: Force Wall and Utter Wall questions
 

I've a good understanding of what a Force Dome and Utter Dome can each block. I'd assumed Force Wall and Utter Wall each repel like the respective dome spells, but a strict reading of the spell descriptions in GURPS Magic throws this into doubt (p. M170).

My primary questions are:

1) Can a magical creature or item cross a Force Wall?

2) Can a magical creature or item cross a Utter Wall?

3) Does an Utter Wall interfere with spells passing through from both sides (see Spell Wall, p. M124)?

Re: Magic: Force Wall and Utter Wall questions
 

What throw you off? They seem quite clear on their descriptions:

Force Wall/Force Dome

Interacts with physical. Blocks physical creatures (Like a charging berserker orc with a 2hander), effects (Like a flying arrow or bullet) and Missile Spells (Like a Fireball, Lightning).

Does NOTHING to magical creatures (Like an elemental from another plane) or effects (Like a Mind Stun from outside to inside or vice versa).

So to answer your question: Yes, a magical creature can cross as if it did not exist.

Utter Wall

Protects PHYSICAL passage from BOTH sides, exactly like a Force Wall, protecting from the stuff I cited above.

On top of that, it also protects against MAGICAL stuff from a SINGLE side, chosen by the caster at time of casting (normally the other side from the one the caster is standing), exactly like the effects described for Spell Wall.

So to answer your question: If its coming from the protected side, it'll be blocked otherwise the magical creature/effect can pass as if it did not exist.

And only spells coming from the protected side suffers impairing and must overcome the Wall protection. Spells coming from the unprotected side pass free, as if the Wall did not exist.

Re: Magic: Force Wall and Utter Wall questions
 

I have treated that part of the description of Utter Wall as errata, assuming it should function identically to Utter Dome and work like a Pentagram rather than a Spell Wall. That way, it will block attempts to cast spells (such as Missile spells) through it. Regular spells can still go around, of course.

Re: Magic: Force Wall and Utter Wall questions
 

Force Wall actually says nothing about magic creatures passing freely through it. Like I originally did, you're making presumptions based on Force Dome's description. How Force Wall works will effect how Utter Wall operates, since the spell effect is described as a combination of Force Wall and Spell Wall (lacking Utter Dome's Pentagram effect, which adds the resistance to magical creatures).

As a GM, my call pretty much mirrors your own, but I'm a player in a game were this is likely to come up soon. While my group often defers to my judgement of the rules, I'd rather have an official clarification or reasonable consensus.

Re: Magic: Force Wall and Utter Wall questions
 

If it says nothing it affects nothing.

Your argument is the same as saying that because, for example, "Ward" Spell doesn't state what happens if used against melee attacks or arrows or flying pies that it should do something with those...

Or that the "Resist Fire" Spell doesn't state what happens if used against acid and because of that should have a special interaction or do something...

Or because the "Steelwraith" Spell doesn't state what happens if you get attacked by ceramic weapons that it should have any effect against it...

Sincerely, to me it's not even close to interpretation...all the rules and cases always specify what they can affect and if there's a special case normally they say so if it cannot affect or has a special effect.

Re: Magic: Force Wall and Utter Wall questions
 

A Force Wall is just a stretched-out, linear Force Dome. It has exactly the same strengths and weaknesses. The only relevant difference is geometry: It doesn't enclose a space, so it can't very well keep out dangerous gases, or maintain an internal temperature or atmosphere (if you sealed a doorway with it, of course, you might be able to arrange for that). Anyway, this means that magic other than Missile spells, and all magical creatures and magic items, can pass right through it.

An Utter Wall is just a stretched-out, linear Utter Dome. The same logic as above applies to it; in particular, it has no interior within which summoning is forbidden. I agree with the interpretation of its protection as Pentagram-like, rather than Spell Wall-like (yes, that's an erratum!). This means that it may prevent weaker magical creatures – ones with low (ST+Will)/2 – from passing through it.

Re: Magic: Force Wall and Utter Wall questions
 

Nice!

As a follow up if you're still around Dr. Kromm, I remember seeing a thread where you specify that a Meteoric Arrow IS affected by the armor granted by the "Armor" Spell...

Considering Force Wall/Utter Dome/Utter Wall are also Protection spells that could be inferred to be an advanced/improved version of the more basic "Armor" Spell, would those also affect a Meteoric Arrow, stopping it or would the arrow simply ignore those and pass as if they did not exist?

Re: Magic: Force Wall and Utter Wall questions
 

I don't remember one specifically about Armor... Was this the one you were thinking of?

Re: Magic: Force Wall and Utter Wall questions
 

I'm fairly sure that he said:
a) A meteoric iron arrow would have to be the entire arrow do this.*
b) A metoric iron projectile would pass through an armor spell. It doesn't pass through a fortify enchantment.

*There aren't actually any rules for this in DF. So you actually can't do it anyway, unless you allow it. We worked out stats for meteoric iron arrows with "The Deadly Spring" here, though. I finally went with:
+70 CF; x5 wt; -1 Acc; +2/die damage; x1/3 range.

Re: Magic: Force Wall and Utter Wall questions
 

Thank you for the clarification Kromm.