Combining extradimensional spaces

[Kerrick]

So far as I know, there's no set rule for combining extradimensional spaces. Placing a bag of holding into a portable hole (or vice versa) is a well-known one, of course, but rope trick also has this caveat at the end of the spell description:

Note: It is hazardous to create an extradimensional space within an existing extradimensional space or to take an extradimensional space into an existing one.

but it doesn't say what, if anything, will happen if you do so. Magnificent mansion says nothing of the sort. So, then, what should happen? I'm of the opinion that you CAN take items that create extradimensional spaces into a rope trick, mansion, etc., but they won't work while inside the other space.

Attempting to create an extradimensional space inside an already existing one (casting rope trick inside a mansion) is a trickier question, though... would it simply fail, or would it cause a rift that would dump everyone out into the Astral Plane, or something else entirely?

 

[Kmart Kommando]

in 3e, nothing would happen.

everything is a holdover from earlier editions, where things were expensive and dangerous. Much like the last line in the dimension door spell. Or the rope trick spell you mentioned.
None of the spells used in the creation of those 'dangerous' items in 3e mention anything bad happening when overlapping them.

If a wizard lost his familiar every time he climbed into a rope trick with a familier pocket, or his entire spellbook from within his handy haversack, don't you think there would be far fewer wizards around that even learn that spell?

Maybe it should say 'material component: everything in your haversack' for the rope trick spell.

 

[Kerrick]

everything is a holdover from earlier editions, where things were expensive and dangerous. Much like the last line in the dimension door spell. Or the rope trick spell you mentioned.

I looked in my 2E PHB, and you're right - they copied the text of the spell, word for word. That PHB doesn't explain the "hazards" of combining extradimensional spaces either, sadly.

If a wizard lost his familiar every time he climbed into a rope trick with a familier pocket, or his entire spellbook from within his handy haversack, don't you think there would be far fewer wizards around that even learn that spell?

Maybe it should say 'material component: everything in your haversack' for the rope trick spell.

Okay, so it was a dumb question. But what do you think about my second question?

 

[azhrei_fje]

My campaign is strictly Core 3.5E, so my ruling is easy: if you cast a spell there's no problem, if you try to bring a permanent extradimensional object into another one expect fireworks.

So rope trick, dimension door, and teleport are all fine with magic items like haversacks and bags of holding. But don't put a bag of holding inside a haversack.

My theory is that non-permanent spells just aren't powerful enough to mess up a permanent magic item. As soon as a spellcaster casts a non-permanent spell, the magic starts draining away. The duration of the spell is how long you have before enough magic is gone that the spell collapses on itself and winks out. Permanent magic items such as haversacks are constantly replenished with magic and when that item "sucks up" more magic to maintain itself, it will "short circuit" any enclosing extradimensional object.

YMMV.

 

[Kmart Kommando]

a handy haversack says it's like a bag of holding, and a bag of holding is a bag of holding. where in the rules does it say you can't put one inside the other?

there is a line that says it is dangerous to do so, but doesn't spell out what that danger is. It could be dangerous because it it'd be hard in battle to go through a couple of nested bags trying to find that healing potion that'll save your cleric's life, maybe.

If you leave dumb stuff like the bag of holding/portable hole interaction in the game, then you're eventually going to get stupid stuff like the arrow i saw somewhere on a forum that had a miniature portable hole and miniature bag of holding, and they came together when you shot it at someone and they went poof! into the astral plane. Lame.

 

[Kerrick]

So rope trick, dimension door, and teleport are all fine with magic items like haversacks and bags of holding. But don't put a bag of holding inside a haversack.

That's about what I figured.

Permanent magic items such as haversacks are constantly replenished with magic and when that item "sucks up" more magic to maintain itself, it will "short circuit" any enclosing extradimensional object.

IOW, if you open a bag of holding inside a rope trick, the rope trick instantly collapses. Fair enough. I would lean the other way - the rope trick is creating the extradimensional space, so you can't create a secondary space (the bag of holding) inside it, because it's not possible to "adjoin" spaces like that.

If you leave dumb stuff like the bag of holding/portable hole interaction in the game, then you're eventually going to get stupid stuff like the arrow i saw somewhere on a forum that had a miniature portable hole and miniature bag of holding, and they came together when you shot it at someone and they went poof! into the astral plane. :roll: Lame.

Okay, yeah, that IS lame. I don't, however, think that nesting bags of holding (or anything similar) is a good idea (from a realistic POV or a game balance one). I would just say that placing any item that creates an extradimensional space (bag, haversack, portable hole, whatever) inside another creates a rift to the Astral Plane and both items are sucked through and lost with all their contents. It's simple, it's logical, and it doesn't break the game or lead to goofy stuff like you stated above. So thanks for helping me come to this conclusion.

 

[irdeggman]

Here is the only combination that causes issues (specified in the bag of holding rules):

If a bag of holding is placed within a portable hole a rift to the Astral Plane is torn in the space: Bag and hole alike are sucked into the void and forever lost. If a portable hole is placed within a bag of holding, it opens a gate to the Astral Plane: The hole, the bag, and any creatures within a 10-foot radius are drawn there, destroying the portable hole and bag of holding in the process.

 

[Kmart Kommando]

That's all well and good, except that the spells used to make the bag-type items, Secret Chest, works by sending stuff to the Ethereal Plane, not the Astral, and Plane Shift automatically goes to the right plane if you have the right focus item, and doesn't work at all without one.

So it is still a holdover from earlier editions that has no place in 3e.

In the game I'm in now, the DM used that line about opening a rift as a plot device to get the party to an alternate universe. Which made us stuck there until we find or make those items ourselves and repeat the process. I found it corny, much keeping with the flavor of the campaign so far.

 

[irdeggman]

That's all well and good, except that the spells used to make the bag-type items, Secret Chest, works by sending stuff to the Ethereal Plane, not the Astral, and Plane Shift automatically goes to the right plane if you have the right focus item, and doesn't work at all without one.

So it is still a holdover from earlier editions that has no place in 3e.

In the game I'm in now, the DM used that line about opening a rift as a plot device to get the party to an alternate universe. Which made us stuck there until we find or make those items ourselves and repeat the process. I found it corny, much keeping with the flavor of the campaign so far.

But the combination of spells and the magic used to create the items (like bag of holding or portable hole) makes a non-dimensional (or extra-dimensional - I think this one is a typo since the term is supposed to be non-dimensional now) space. So do not merely rely on the spells used to create an item to give the full description of the resultant item - there are other things that occur when creating a magic item.

This appears to be a common cloth sack about 2 feet by 4 feet in size. The bag of holding opens into a nondimensional space.

When spread upon any surface, it causes an extradimensional space 10 feet deep to come into being.

 

[Kerrick]

That's all well and good, except that the spells used to make the bag-type items, Secret Chest, works by sending stuff to the Ethereal Plane, not the Astral, and Plane Shift automatically goes to the right plane if you have the right focus item, and doesn't work at all without one.

And frost weapons require ice storm. That doesn't mean I can use one to cast an ice storm - it's just the closest spell they could find to achieve the desired effect. All planar travel goes through the Astral, and any time you see extradimensional spaces being destroyed and dumping their contents/occupants, it's into the Astral.

But the combination of spells and the magic used to create the items (like bag of holding or portable hole) makes a non-dimensional (or extra-dimensional - I think this one is a typo since the term is supposed to be non-dimensional now) space.

You know, I think you're on to something there. Bag of holding defines a nondimensional space as "Its inside is larger than its outside dimensions." At first I thought, "So what's the difference?" And then it hit me - an extradimensional space is effectively a small pocket plane - it's not a container, it's a place accessed by a portal or doorway. By that logic, a portable hole is indeed an extradimensional space, because it's not a true container - it's a flat piece of cloth you lay out on a surface and reach into to grab whatever you want, as opposed to the bag of holding and handy haversack, which are actual, portable, containers that hold far more than they should.

Now, rope trick says, "The upper end is, in fact, fastened to an extradimensional space that is outside the multiverse of extradimensional spaces ("planes")." I would take that to mean "a nondimensional space", which would also explain the warning at the end of the spell. But, by the above logic, this would be incorrect, since it's not a container. So effectively, spells create extradimensional spaces, items create nondimensional spaces, and nary the twain shall meet (IOW, it would be a bad idea to open one inside the other).