Dimensional Anchor and Mordenkainen's Magnificent Mansion

[Someonelse]

If someone cast Dimensional Anchor on a mage, would that mage be prevented from casting and/or entering a Magnificent Mansion?

I'm thinking no, but I'm hoping someone will say yes.
Please explain your answers.
Thanks

[CombatOwl]

If someone cast Dimensional Anchor on a mage, would that mage be prevented from casting and/or entering a Magnificent Mansion?

I'm thinking no, but I'm hoping someone will say yes.
Please explain your answers.
Thanks

No it does not, because magnificent mansion is not mentioned specifically by dimensional anchor and cannot logically be considered a spell similar to any that was mentioned. It's the same reason that someone subject to a dimensional anchor can still stick their hand in a bag of holding.

Essentially, dimensional anchor stops travel to different planes--all of the spells that it blocks are specifically spells that move the caster at least partially into another plane. Unfortunately, the rules in D&D use "nondimensional" and "extradimensional" interchangeably in reference to various things. Extradimensional spaces can also be considered "nondimensional spaces." Entering them does not constitute extraplanar travel.

[Someonelse]

Dimensional Anchor blocks all forms of extradimensional travel. Magnificent Mansion creates an extradimensional space. You then TRAVEL into this space when you cast the spell. So this is why I think it would not work.
Since you bring up the bag of holding it sort of makes sense that they couldn't access a bag of holding or portable hole while dimensionally locked either.

[Chronos]

There's nothing stopping you from casting the spell, but you can't then enter it.

[Duke of Urrel]

My first inclination was to agree with CombatOwl. I have always distinguished extradimensional (or nondimensional) spaces from other planes of existence in my mind, and I have always imagined that the rules also made a clear distinction between extra-planar spaces, which are actually on a separate plane and lie on the far side of an interplanar boundary, and extra-dimensional spaces, which are only extrusions or pockets of one and the same plane of existence inside of itself.

So I looked carefully at the text of the Dimensional Anchor spell. And there I found the phrase "completely blocks extradimensional travel." Extra-dimensional, not extra-planar. The list of spells that are affected by the Dimensional Anchor spell, conveniently provided for us in this spell's description, demonstrates that in this text, the phrase "extradimensional travel" also refers to extra-planar travel. But nothing suggests that the word "extradimensional" refers exclusively to extraplanar spaces behind interplanar boundaries.

So now I am inclined to agree with you, Someonelse, that the Dimensional Anchor spell blocks access to extradimensional and nondimensional spaces as well as extraplanar ones. A Dimensional Anchor would therefore not only prevent me from teleporting, blinking, becoming ethereal, shadow walking, or passing through an interplanar gate, portal, or vortex. It would also prevent me from entering a Portable Hole, a Magnificent Mansion, or the space at the top of the Rope Trick spell; and it would prevent me from reaching inside a Bag of Holding or a Handy Haversack.

Having said this, I am now pondering whether we ought to consider all of these extradimensional interfaces to block line of effect for spells, just as interplanar boundaries do. The entrance to the space at the top of the Rope Trick spell does this explicitly, but no other entrance to any extradimensional space I know explicitly blocks line of effect. The entrance to the Magnificent Mansion blocks unwelcome intruders, and the opening of a Bag of Holding or a Portable Hole blocks air, but it isn't stated anywhere that these openings block spells.

So there may still sometimes be a functional difference between interplanar interfaces and extradimensional ones: whereas the former block line of effect for spells (except for those that "work across planes"), the latter may or may not. It would be simpler to say that extradimensional interfaces block line of effect just as interplanar ones do. This interpretation would, of course, make some of these extradimensional spaces even better protected than the rules explicitly make them. Maybe that's all the more reason to give the Dimensional Anchor spell the power to block access to these spaces.

Postscript: This interpretation would also make it impossible to Teleport either into or out of an extradimensional space. The Plane Shift spell might still provide access, but you'd have to have a special focus keyed to the particular extradimensional space you wanted to enter, and I doubt that you can create a focus like that for some other spellcaster's Magnificent Mansion, or even for your own. On the other hand, I should think the Plane Shift spell ought to provide you with a way to escape from a Bag of Holding or a Portable Hole. The Gate spell also might have the power to re-open a Portable Hole or a Magnificent Mansion after it has been closed from the inside, and it might enable anyone to escape from a Bag of Holding or a Portable Hole to anywhere else in the multiverse.

[ericgrau]

Any creature or object struck by the ray is covered with a shimmering emerald field that completely blocks extradimensional travel.




You conjure up an extradimensional dwelling...the place can be entered only through its special portal

I fail to see what's so complicated about this. Unless you try to make it complicated because you want to worm your way out of it. You can cast the spell but you can't travel into the mansion. Examples cannot change this, they can only clarify it, and maze and gate help do so.

[Psyren]

Thirding Chronos and ericgrau - you're stuck outside.

[Duke of Urrel]

Here's a related question. Suppose you have been hit by the green ray of the Dimensional Anchor spell, so that you now cannot pass through extradimensional boundaries yourself. Can you still use the Plane Shift spell or the Teleport spell to enable others to travel instantaneously through the Astral Plane, even though you can't follow them yourself?

I believe you can. You can bestow the Plane Shift or Teleport spell by touching your comrades or forming a circle with them, as usual, and thereby make them all vanish, but you must remain behind.

[ericgrau]

You clearly can with plane shift because it says you can affect (only) others specifically in the description. And since you are not part of the travel then yeah it should work fine.

With teleport you bring others with you so I don't think anyone would be transported. It's not 100% explicit but it seems implied throughout the entire spell text so it's the best answer we have with the information available (but if you can dig up more teleportation rules then by all means do so).

[Psyren]

I would say the whole spell would fail if you try to include yourself. But it's not clear.