Enlarge person and gear question

[Crow_Nightfeath]

So the question is, how does enlarge person affect gear like ropes? As long as you remain in contact with it it stays enlarged, so how does that affect the length, break DC and how much weight it can support?

[Kaleph]

As a DM, I'd rule that the ropes don't change size, but you get a free attempt to break them (this could be in my eyes an automatic success).

The article here gives some fairly clear explanation: http://archive.wizards.com/default.asp?x=dnd/rg/20050510a.

If you believe they increase in size, the HP of the rope increase (http://www.d20srd.org/srd/exploration.htm#smashinganObject), but nothing is said about the DC to break it - this is because the WotC thinks that the DC doesn't depend too much on the material, but rather on the construction, i.e. the way the rope is tied.
Anyhow, a bit further down, they explain that the DC to break an object decreases by 2 if it loses 50% of its HP; an increase in size should give the rope 200% HP (so 4 HP if the thickness changes from 1" to 2"), which corresponds to a +2 DC. Considering that a Standard size increase gives a creature +8 strength (or +4 strength Bonus), and enlarge Person +2 strength (or +1 sterngth Bonus), this houserule seems pretty balanced.

Sorry for tinkering with it a bit, but I couldn't find a specific rule that covers your case; possibly some other user may be luckier than me in his Research...

EDITed to correct some math Errors :-)

[Akkristor]

Enlarge Person doubles the objects dimensions in all 3 dimensions, so the rope is twice as large around, and twice as long.

A rope's ability to support weight is (roughly) proportional to it's cross-sectional area, so the doubly thick rope should be able to support (roughly) 4x the weight. Note that the rope now weighs 8x it's prior weight. A Silk rope has a break DC of 24, so a character with 18 strength can break the rope at maximum exertion (nat 20/take20, +4 modifier). A medium creature with that strength has a maximum lift capacity of 300lbs, and a maximum push capacity of 1500lbs, so it's safe to assume that a Silk Rope will snap at about 1500lbs. An Enlarged Silk Rope, then, would be able to support 6000lbs, and go from weighing 5lbs to 40lbs.

As for break DC, That'd be up to the DM, no hard and fast rule. Silk ropes have double the Hit points of hemp ropes, but only +1 on the break DC. I'd suggest adding +2 or +5 to the DC myself, since check DCs aren't on a linear scale. Doubling a DC does not make a check twice as hard, after all, it likely makes it impossible.

[Segev]

As for break DC, That'd be up to the DM, no hard and fast rule. Silk ropes have double the Hit points of hemp ropes, but only +1 on the break DC. I'd suggest adding +2 or +5 to the DC myself, since check DCs aren't on a linear scale. Doubling a DC does not make a check twice as hard, after all, it likely makes it impossible.

On check DC math, as long as you're within the range where the d20 can make a difference, a +1 or -1 is a 5% shift. Now, whether "twice as difficult" means "half as probable" or means something else entirely is a separate question.