How to get into a Mordenkainen's Magnificent Mansion

[Samloyal23]

The plane is a folded subspace created by the caster. How is it even detected? How do you find, let alone open the door? I do not mind the food, just think about the holodecks and replicators on in Star Trek. Objects on a holodeck are made of "proto-matter" held together inside the holodeck. The particles that make up a piece of food on the holodeck get integrated into your body when you are in the holodeck. Once you leave anything you can disintegrates, turning into virtual particles that speed off in random directions. Anything you are is bonded to atoms in your body first, so they hold together. The magical food in an MMM is the same, once you digest it, it becomes a part of you.

 

[Greenfield]

I know a somewhat predatory DM who scoffs at the MMM as some unassailable place.

His standard response is, "Use Tracking to find their trail when it disappears use See Invisible to spot the doorway. (It is described as being Invisible, so his should work). Then they set up their assault and somebody throws Dispel Magic, dumping the party outside with no warning and no prep time."

Now in his games, his bad guys can *ALWAYS* track you, they *ALWAYS* know when to use Detect Magic and See Invisible to spot guards and traps, and their Dispel efforts always work, no dice roll.

So he's not always a very fun DM to play with, but he is right about how to find the Mansion. Unless the entire party has Pass Without Trace, Tracking can lead them to the area of the door, and See Invisible can show them its exact location.

 

[TalesWithinWheels]

That DM does seem a little unreasonable, but you're right, his methods do work. A more reasonable approach would be to simply have monsters and NPCs with True Seeing happen across the portal.

As for the extradimensional spaces argument, I know its an old one, but I don't think it's settled.While it was certainly inconsistently applied by authors, leading to the odd condition that it RAW, works only with bags of holding and portable holes, that begs the question: Why? I have no difficulty imagining that two extradimensional spaces could not co-exist within each other. Even that has only the vague cautioning against it. But, I think I recall reading some time ago a clearer prohibition of it. Whether it was in D&D or not, I don't remember, that cleared up the issue by specifying that two extradimensional spaces within each other were ripped apart and sent their contents hurtling into the Astral Plane. So, under that interpretation, you can definitely "breach" MMM by sneaking in an extradimensional space. That takes a lot of prep work, however, and the contents of the MMM ending up in the Astral doesn't always make them more accessible...

 

[Scorpio616]

There are reasons whey Arcane Sight can be permanency'ed. These spells are one of them. 3Era D&D will often come down to Dispel Magics, and later on Disjuntions.

 

[Scorpio616]

The plane is a folded subspace created by the caster. How is it even detected? How do you find, let alone open the door?

Detected by the "entrance on the plane from which the spell was cast." Magical auras stay visible, so Arcane Sight will do the trick. Still can't open it, but Greater Dispel will get rid of the spell.

 

[Samloyal23]

I am slowly building a campaign setting and one of my cities has many "buildings" that are permanent mansion spells built into enchanted stones and trees. I am thinking only a Disjunction would affect them, no? And can you choose to change the shape or size of the portal? Let's say you embed a portal into the side of a cliff, any reason you cannot make it 20 feet across?

 

[Greenfield]

Well, after a caster passes 10th level Dispel Magic becomes less and less effective. If you can boost your caster level to 20, it becomes impossible for someone to take down your spells with DM. It's all in the numbers:

At CL 20, the opponent needs to roll a natural 21 on a D20 to take down your spell. They can only add 10 caster levels to their D20, and then beat your caster level by 11.

Greater Dispel stays effective up to CL 20, then starts to fade as well.

So Dispel Magic might take down the permanent spells. Greater Dispel has a better chance. Disjunction isn't really needed.

Moving on to other topics, I'm not sure what happens when a Rope Trick or Magnificent Mansion spell ends or is dispelled while a Dimensional Lock is in effect in the area.

The RT or MM spell has to end, but the contents can't return to the material plane. The DL spell says that they can't.

It's sort of an "Irresistible Force" v "Immovable Object" situation.

 

[Scorpio616]

Moving on to other topics, I'm not sure what happens when a Rope Trick or Magnificent Mansion spell ends or is dispelled while a Dimensional Lock is in effect in the area.

The RT or MM spell has to end, but the contents can't return to the material plane. The DL spell says that they can't.

It's sort of an "Irresistible Force" v "Immovable Object" situation.

Is the being affected indestructible? Since the victim is stuck between "Irresistible Force" of being forced back to reality and the "Immovable Object" of the Dimensional Lock, I'd rule they implode then the remains get sprayed out into the Astral plane.

 

[Samloyal23]

Is the being affected indestructible? Since the victim is stuck between "Irresistible Force" of being forced back to reality and the "Immovable Object" of the Dimensional Lock, I'd rule they implode then the remains get sprayed out into the Astral plane.

Roll a casting check to see which spell is more powerful. If the result is a tie then a rip in space occurs and everything inside the spell and possibly outside near the portal gets sucked into the Silver Void...