D&D 5E Mordenkainen's MOBILE Mansion? Opinions wanted

[AaronOfBarbaria]

...this whole train of thought began when I found myself wondering if one could use interdimensional magic spells to allow an entire party to travel inside an apparatus of Kwalish.

I once had a party unfold their portable hole inside said apparatus in order to make room for passengers. I saw nothing wrong with it then, and I see nothing wrong with it now.

 

[Dannyalcatraz]

I'll give it an unqualified "yes".

Though honestly, I thought this was going to be a discussion about putting it on 4 Tenser's Floating Discs, and towing it with Mordenkainen's Hound or Figurines of Wonderous Power...

 

[Mouseferatu]

I once had a party unfold their portable hole inside said apparatus in order to make room for passengers. I saw nothing wrong with it then, and I see nothing wrong with it now.

Oh, I'd absolutely allow that. That was my first thought.

It's just that a 6 ft.-diameter space isn't going to accommodate three people unless they get real friendly, and not for any real length of time. Plus--unlike Mordenkainen's magnificent mansion--the amount of air in a sealed apparatus becomes a problem.

But definitely a viable stopgap solution, at least.

 

[Mouseferatu]

As far as the whole "does it move with the planet," I really tend not to worry about such things. Yes, the planet rotates. Yes, "immobile" things still move with it, just as things we consider immobile--like, say, mountains or buildings--do so IRL. I'm not concerned with whether magic interacts with the laws of physics on a planetary scale the same way it does on smaller scales.

In the end, in a setting with real and measurable gods, I'm perfectly happy with saying, "Because the gods created it that way, that's why," if there's ever a laws of physics hiccup.

 

[Ancalagon]

Just for context--though obviously I didn't/don't want to limit the conversation to just this, or I'd have said so in the initial post--this whole train of thought began when I found myself wondering if one could use interdimensional magic spells to allow an entire party to travel inside an apparatus of Kwalish.

Add a time traveling device and you have a mechanical lobster-TARDIS

 

[Ancalagon]

That being said, I thought this thread was going to devolve into Mordenkainen's siege tower

 

[Uchawi]

Unless an effect considers movement, or it moves itself, then I would consider it anchored at a fixed point. Otherwise, a special effort would need to be taken to broaden the scope ala bag of holding (movable extra dimensional space), or anchoring an effect to an item.

 

[Ahglock]

Oh, I'd absolutely allow that. That was my first thought.

It's just that a 6 ft.-diameter space isn't going to accommodate three people unless they get real friendly, and not for any real length of time. Plus--unlike Mordenkainen's magnificent mansion--the amount of air in a sealed apparatus becomes a problem.

But definitely a viable stopgap solution, at least.

6' diameter will comfortably fit 3 people for relatively short times. My couch has 6' of sitting space it easily fits 3 guys. Shoulders don't even touch. Now in plate if think it would. Still that's 6 foot line not diameter. Throw down 3 chairs and they'll be fine.

 

[Saeviomagy]

So, there's no RAW answer to this, and that's fine. I'm looking for opinions and repercussions.

If someone were to cast Mordenkainen's magnificent mansion while aboard a vessel (such as a ship), would you permit the entryway to move with the vessel? Why or why not?

It moves with the ship. Why? Because if you made a 7th level spell that did this sort of thing, you would want to be able to use it in your cabin on a ship, inside your covered wagon, or anywhere else. It's magic: why the heck would you make this spell and then not allow you to pick the frame of reference arbitrarily?

Secondly - letting it work that way doesn't break anything, it just makes the spell more useful to do what it already does.

Now, all that being said, I view the section on who can and cannot enter the mansion to be awful. I would change it to be "you and anyone you designate when casting the spell can open and close the portal while within 30ft as an action" and "any creature or object can enter the extradimensional space as long as the portal remains open". Otherwise it can be used as a safehouse during combat, which I think is a bad thing.

 

[Samloyal23]

A portal for an MMM spell has to be drawn on a solid surface big enough to be used as a door for the caster. It is always fixed and immobile relative to the frame and surface it is painted on...