There is so much speculation about the future direction in this thread that it might be hard to see the actual points Monte's making, but I'll give it a try.
In my mind generally, what rules you make are about what intent you have for your game. You have rules for things you want to do. These rules allow players to contribute in interesting and varied ways. With quick, simple rules, you don't want to spend much time in the area, meaning that it's not a place for any
dramatic tension.
If you want dramatic tension, you need a chance for failure, and a consequence for failure, you need to slow down, and you need to roll dice.
[sblock=the breakdown]
First Option:
Monte Cook said:
Obviously, the first example is extremely sparse. If that were the rule, there might be a rule somewhere else that suggests that anytime you have your hands full and are preoccupied, you grant combat advantage. But the idea of the approach is to let the DM make calls as she sees fit, using logic and circumstance as her guide. In a game with this rule, the DM might only call for a check to climb if it seemed appropriate.
IMO, the first rule is weak for D&D.
The rule in the first example says to me as a player that climbing is not something that is interesting. It is to be gotten out of the way as quickly as possible. There is little or no risk in it. If you want to impose all sorts of disasters from the outside, no one is stopping you (DM Fiat!), but unless it is an exceptional situation, you should just let people climb all over everything.
So it is great if you are playing SPIDERMAN, THE RPG. Or if your character is an advanced theif, or has
slippers of spider climb. Or otherwise does not risk much by climbing about. But in general, I want some tension and risk in my climbs. It's not that auto-climbing is
unrealistic (though it is that), it is that auto-climbing is
boring. There's no game to play. Move along, folks, nothing to see here, the fun part is somewhere else in the game, this is boring stuff we just want to get out of the way quickly.
Second Option
Monte Cook said:
The second example is slightly meatier, and in no way contradicts the first. However, it suggests that there is a mechanic for determining success. That might seem like a small thing, but it's not. It changes the entire expectation of the act of climbing. Now the player reading the rule not only knows that some climbs are harder but also expects that some characters and creatures are better at making them. The reader also knows that there is a set combat effect of climbing, and the rule requires that he understand what "combat advantage" means. Still, the difficulty of each individual climb remains entirely in the hands of the DM, as are corner-case situations such as falls. Using this rule, for example, some DMs might call for a saving throw while others might ask for another climb check in order to allow someone to catch themselves.
IMO, the second example has many of the same problems as the first.
Up above, I said that there was no tension at all in the climb. This introduces some tension in the form of a roll, and a consequence for your action (CA), but it doesn't give you any guidance about what happens when you fail that roll. "Falls" are not a corner-case situation, they are a core part of the tension involved in any climb. It is what you are trying to avoid. I dang well better have rules for falling in my rules for climbing, if it is meant to provide tension. CA is also problematic, because it is meaningless outside of combat, implying that the only interesting time you can be climbing something is during combat. This shares the same problem as the first example in any out-of-combat situation in that there's no risk or tension, and in any combat situation, it doesn't provide a satisfying risk, since you can't fall. It's a pretty useless rule, all told. It gets in the way, and then has no follow-through.
Third Option
Monte Cook said:
The third example does not contradict the other two but is expansive in detail. DCs are set, corner-cases are covered. It takes most of the assumptions of the second version and sets everything further in stone. It ensures that everyone's going to be using climbing in their game the same way, and it doesn't force the DM to make any on-the-fly decisions about how climbing works in the game. At the same time, it's potentially cumbersome in its description and the amount of information provided, at least compared to the other two. In a game using this rule, it's easy to imagine that any time someone wants to climb a surface, someone's going to crack open a book to check the mechanics of it.
IMO, the third option is overly cumbersome, but contains the best core of the rules for a risky climb.
You could have more detail than Option 3 presents, of course. In a game that made climbing a central theme (such as a game about climbing Everest), I'd expect rules for oxygen deprevation, windspeed, surface angle, humidity, weather, frostbite, rising sweat, silk rope vs. hemp rope vs. chains, and all sorts of corner cases that Option 3 doesn't cover that make ACTUAL climbing thrilling and interesting.
That's not even very simulationy, honestly. If you want simulationy, go with the mechanics found in
GRIP: it pretty accurately simulates the thought process of an actual rock climber: Aim. Flex. Grab. Aim. Flex. Grab. To do this in D&D, you'd have something like a round cycle: the Aim action (is there a handhold near you?), the Flex action (can you control your body well enough to hit it without going too far), and the Grab action (does the rock hold?). If each of these involved a die roll, perhaps with degrees of failure so that you could fail each stage without failing the whole climb and falling to your death, that would be a LOT of tension, and fairly accurately sim-y the tension of a climb.
But D&D isn't really a game that makes climbing a central theme, so that level of detail isn't really necessary. We only want enough detail to make rolling a d20 to attempt to climb something a risky proposition. We need to figure out what climbers want to do, and then design rules that allow them to do that.
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With that in mind...
Fourth Option
Climbing (Exploration): When you're exploring the world, you will sometimes want to climb around on things: climbing up trees to get a view, or climbing up a rocky wall, or climbing up a rope. Generally, you can Take 10 on these checks, automatically climbing any surface with ample handholds (examples: A tree. A rocky wall. A knotted rope. Level 1, Easy DC). These common climbs aren't risky, and, assuming you're not in combat, are done more or less automatically (though especially frail characters may need to roll a check).
Certain climbs are harder or riskier: climbing up an ice wall, or a smooth brick surface, or a wall slick with ooze, is going to require some skill. The DM will set the DC's of these climbs, based on their judgement and the specific circumstance. While you can Take 10, many of these climbs will have a DC too high to Take 10 on, at least at low levels (Medium DC or Hard DC, any level). If you make the check, you succeed in climbing the object, or succeed in climbing a portion of a larger object that takes multiple checks to climb.
If you fail a Climb check, you make no progress, and you risk falling: you must make an immediate Climb check to hold on, and if you fail this second check, you fall (and take falling damage). If you succeed in this check, you are stuck on the surface; you can try again to climb, if you want, or you can lower yourself off without needing another check.
Climbing in combat is harder, and is covered in the Combat chapter, under Moving.
[sblock=combat notes]
If you're going with 4e style minis combat:
Generally, the clash of attacks and fast action make it impossible to Take 10, and climbing itself exposes you. In combat, you can make a Climb check as a standard action, and, if you beat the DC of the surface, you can climb up to half your speed. If you fail, you risk falling as above. You grant combat advantage while you are climbing, and any attack that hits you makes you risk falling as above (though if you succeed, you don't have to stop).
If you're going with cinematic combat:
Roll an Athletics check to climb up an object onto higher ground. This gives you Distance against all creatures who are not on the object (meaning you can make ranged attacks, but not melee attacks). If you fail, you risk falling as above.
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Some creatures are such great climbers that they don't even need to roll a skill check: these creatures have a climb speed, and treat vertical movement like any other movement. To most giant spiders, for instance, a wall is just a floor on its side. Of course, if these creatures fall while climbing, they might suddenly be reminded of gravity's authority. Other creatures have very good skill checks, and so can Take 10 on very difficult climbs, but might have problems holding on in combat, or on the most extreme of climbs. A ring enchanted with the power of ninja forest monkeys might give you a climb bonus of +5, for instance, but that +5 might not matter when you're trying to climb up the rain-slick precipice of darkness -- +5 might not be enough to scale it, if it is a level 10 challenge with a hard DC, and you're only first level, even if you are a good climber...for first level.
This basically boils climbing down into auto-completed territory, with checks for tense climbs, and more checks possible if the DM wants to make an especially complex wall to climb. Penalty for failure is damage and possible death. There's tension. You don't need to roll for everything, since you can Take 10 and conquer simple things easily. Where it gets messy is combat, and that's mostly because grid combat cares about stuff like OA's and squares moved and other stuff that doesn't matter if you take a cinematic approach. If you take that cinematic approach, you again go back to one-check-and-its-done territory, since we don't care what exact squares you're moving through, and OA's don't exist.
In Closing:
I find it kind of fascinating that Monte decided to use "Climb" for the skill name rather than ATHLETICS. Already he's assuming a certain level of granularity -- that it matters what you can Climb vs. what you can Swim or Jump -- that might not be true.
The main complications from climbing (squares moved, combat advantage, etc.) come from combat, and that's a problem
with combat, not with climbing per se.