D&D 5E I'm the DM and a player is trying to abuse the Immovable Rod. Advice?

[AaronOfBarbaria]

If you build a platform out of them then you need only count the weight directly resting on a given rod. have enough and the weight will be split to less than 8k per rod.

That's one of those things that is a fine way to handle it, but not actually what the rules for the item in the book says, since the item mentions nothing about being able to share a load with some other means of support, but explicitly says "More weight causes the rod to deactivate and fall."

The rules of D&D and physics don't mesh all that well in general, but this is a specific example of how they don't - sharing a 8,001 pound load with another rod would mean less 8,000 pounds of force exerted upon each rod, but since that is more than 8,000 pounds of weight, both rods would still deactivate.

 

[Maxperson]

If you build a platform out of them then you need only count the weight directly resting on a given rod. have enough and the weight will be split to less than 8k per rod.

I thought about that, but the rods don't really say that for certain. They say that it can only hold 8000 pounds and a house is over that. This would be a case of rulings over rules, since the rule could go either way.

 

[Yunru]

That's one of those things that is a fine way to handle it, but not actually what the rules for the item in the book says, since the item mentions nothing about being able to share a load with some other means of support, but explicitly says "More weight causes the rod to deactivate and fall."

The rules of D&D and physics don't mesh all that well in general, but this is a specific example of how they don't - sharing a 8,001 pound load with another rod would mean less 8,000 pounds of force exerted upon each rod, but since that is more than 8,000 pounds of weight, both rods would still deactivate.

It's not the rules, it's physics. an 8001 pound load evenly on two rods puts a 4000.5 pound load on each rod. 4000.5<8000. Since no rod has more than 8000 pounds on it, no rod deactivates.

 

[sandvirm]

That's one of those things that is a fine way to handle it, but not actually what the rules for the item in the book says, since the item mentions nothing about being able to share a load with some other means of support, but explicitly says "More weight causes the rod to deactivate and fall."

The rules of D&D and physics don't mesh all that well in general, but this is a specific example of how they don't - sharing a 8,001 pound load with another rod would mean less 8,000 pounds of force exerted upon each rod, but since that is more than 8,000 pounds of weight, both rods would still deactivate.

It just takes a little more engineering. The house could be built in small sections, none weighing more than a couple thousand pounds. Then the sections are simply placed close enough to create a house, but aren't actually connected. It would have leaks and drafts, but that just adds character for some villainous homeowners. Or maybe budget for the price of weather controlling spells in the construction costs. It should also probably be all on one floor to minimize potential loss. A collapse on a floor above would cascade all the way out the bottom.

 

[Maxperson]

It's not the rules, it's physics. an 8001 pound load evenly on two rods puts a 4000.5 pound load on each rod. 4000.5<8000. Since no rod has more than 8000 pounds on it, no rod deactivates.

Magic doesn't require physics, though. The magic might only look at the weight of the entire object. This is a DM rulings thing.

 

[ccs]

It's not the rules, it's physics. an 8001 pound load evenly on two rods puts a 4000.5 pound load on each rod. 4000.5<8000. Since no rod has more than 8000 pounds on it, no rod deactivates.

Well, you're playing D&D.... In case you haven't noticed physics is a pretty optional force.

 

[sandvirm]

This thread is giving me ideas for traps that have a chance of rewarding the players with an Immovable Rod, either removed from the disarmed trap or excavated from the rubble after it goes off.

 

[Maxperson]

Well, you're playing D&D.... In case you haven't noticed physics is a pretty optional force.

Yes and no. Physics exists in D&D. You fall when you walk off a bridge. You have to swing or thrust with a sword to damage someone. If you throw something it doesn't go on forever. There are two important considerations when looking at D&D physics, though. First, it doesn't model the real world exactly, so trying to argue real world physics as proof of how it works in D&D is doomed to failure. At best you can look at real world physics for a general idea. Second, magic can, and very often does overcome D&D physics.

With the rods, we don't know if or how the magic interacts with the D&D physics, so it's a DM call.

 

[tglassy]

Lol, not it’s not. Wood has a stress limit. Suspension wiring has a stress limit. Hell, the human arm has a stress limit, but if you distribute the weightaccordingly, according to physics, one human arm can move a massive ship from themiddle of a city to the coast. It’s beendone. I think it was Archimedes who saidhe could move the earth if he had but another earth in which to put hislever.
Having an 8001 lbs house on two rods doesn’t automaticallymagically make both rods having to lift all 8001 lbs. That’s nonsense. Here’s the rule: The rod can hold up to 8,000pounds of weight. More weight than thatwould cause the rod to deactivate and fail.

It doesn’t say it can only hold up objects that weigh lessthan 8,000 lbs. It says that it can holdup to 8,000 lbs. If you evenlydistribute 8,000 lbs on four rods, then each rod is only holding up 2,000lbs.

It’s called physics. I understand this is a magical item that is already breaking the laws ofphysics, but it is very specific in the manner in which it breaks them. It causes the rod to become fixed inspace. No other laws of weightdistribution are affected.

Here’s another example. If you and I were to lift something that weighed two hundred pounds, andeach of us can only lift 120, will we be unable to lift it? No. Because each of us, assuming it’s evenly balanced, will only be lifting100 lbs.

I could go on, but this is a dead horse at this point. A floating house would be awesome, and a verygood and unique way to use items like this, if you could afford the number itwould require.

…until someone came up and started pressing the buttons todeactivate them. Deactivate enough ofthem, and the house comes tumbling down…

And as far as magic not requiring physics, this is alsoa false statement. A fireball createsfire, and then the fire does its thing. The “Levitate” spell can make a person float, but they still havemass. A poison dart spell pumps poisoninto a person, which only affects them if poison affects them.

Physics is avery real thing in a magical world. Magic is just a way to do things that are otherwise impossible throughphysics, like creating something out of nothing. That something still has mass, thingsaffected by magical spells are affected according to physics, unless the spellfurther breaks those laws, specifically. Unless you make sure to create a fireball spell that specifically doesn’tburn things, it’s gonna burn things when its cast.

If nothingelse, wizards are the scientists of the DND world, as they understand the lawsof physics better than anyone, because you need to understand the laws in orderto understand how to break them. Or at least, those wizards who invented spells understand physics. Everyone else is just copying.

 

[Maxperson]

::a lot of stuff that doesn't matter because D&D doesn't model real world physics and magic changes physics anyway::

That's a nice explanation for how they would work in the real world, IF magic worked in the real world. However, it doesn't apply to any game but your own and those DMs who decide to house rule in real world physics for some reason.

It's a DM call on whether it works or not. Plain and simple.