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Pen & Paper Roleplaying Central => Pen and Paper Roleplaying Games (RPGs) Discussion => Topic started by: mcbobbo on September 05, 2014, 01:40:15 PM

Title: 5e Combat Simulator? (Because we all know Bob sucks at Math)
Post by: mcbobbo on September 05, 2014, 01:40:15 PM
I would like to prove what seems to be an obvious point in my mind's eye about the relative combat strength of some of the foes in Phandelver.

Is there a 5e simulator online somewhere?  Google thinks no...

Is there napkin math that makes sense?

We can do the specifics if need be, but my question is more about tools.  Maybe I should just enlist someone to run through some sample fights against me?

I want to make the case that 'X could easily kill Y' and back that up somehow.
Title: 5e Combat Simulator? (Because we all know Bob sucks at Math)
Post by: Omega on September 07, 2014, 08:07:06 AM
Well you could use any dice roller or by hand to do the to-hit rolls and then apply average damage and see who drops first depending on what bonuses are applying or not?
Title: 5e Combat Simulator? (Because we all know Bob sucks at Math)
Post by: Ladybird on September 07, 2014, 08:37:59 AM
Basic understanding of probability (Wikipedia will be fine for this, as basic maths isn't something that can be argued about, or Khan Academy), some sensible assumptions about combat, and a spreadsheet, will get you a long way.

Obviously you won't be able to predict everything that would happen in a game with 100% accuracy, but you're probably not trying to, so as long as your assumptions are sensible then you're fine.

eg. Let's consider the Goblin attacking the PC's in melee. The melee combat guys in the starter set have AC 17 and 18, let's call that 18 for the sake of argument, so the Goblin needs to roll 14+ to hit; means it hits 35% of the time. For damage, d6+2 averages out to 5.5 (Average roll of d6 is 3.5, plus 2). 35% of that (Because only 35% of it's attacks hit) gives us the goblin doing 1.925 damage. Same maths for AC 17 gives 2.2, so we can say that the goblin does about 2 damage per round against the hard melee targets.

Against the non-melee types, let's say AC 12 (Because they're 14, 14, 12). Goblin hits 60% of the time. 60% of 5.5 gives 3.3 DPR. Against AC 14, it's 2.75, so let's round that to say the goblin does 3 DPR against soft melee targets.

Working out the values for the PC's attacking the goblin is left as an exercise for the reader.

It helps that there are average damage numbers for most of the monsters, so that's a bit of maths saved, but the difference between using that and true average die rolls isn't going to be significant.
Title: 5e Combat Simulator? (Because we all know Bob sucks at Math)
Post by: mcbobbo on September 08, 2014, 12:23:20 PM
Quote from: Ladybird;785603eg. Let's consider the Goblin attacking the PC's in melee. The melee combat guys in the starter set have AC 17 and 18, let's call that 18 for the sake of argument, so the Goblin needs to roll 14+ to hit; means it hits 35% of the time. For damage, d6+2 averages out to 5.5 (Average roll of d6 is 3.5, plus 2). 35% of that (Because only 35% of it's attacks hit) gives us the goblin doing 1.925 damage. Same maths for AC 17 gives 2.2, so we can say that the goblin does about 2 damage per round against the hard melee targets.

Against the non-melee types, let's say AC 12 (Because they're 14, 14, 12). Goblin hits 60% of the time. 60% of 5.5 gives 3.3 DPR. Against AC 14, it's 2.75, so let's round that to say the goblin does 3 DPR against soft melee targets.


Okay, cool.  By focusing on the average values you're nullifying the need for actually generating the battles.  Interesting.

You're going to need a similar number for spells and powers, though, when boiling things down to DPR.  E.g. Invisibility is what, 0 DPR for your opponents for some number of rounds?
Title: 5e Combat Simulator? (Because we all know Bob sucks at Math)
Post by: Exploderwizard on September 08, 2014, 02:04:13 PM
Quote from: Ladybird;785603It helps that there are average damage numbers for most of the monsters, so that's a bit of maths saved, but the difference between using that and true average die rolls isn't going to be significant.

Keep in mind when dealing with averages that they are a more useful tool when dealing with HP pools large enough to matter. Its harder to figure an average for a single roll, and that single roll on the high end can put down a soft target.

Sample size is everything. A goblin doing 3 average damage is a small comfort when the actual range is 3-8 and you have 7 hit points. :p
Title: 5e Combat Simulator? (Because we all know Bob sucks at Math)
Post by: Ladybird on September 08, 2014, 02:50:33 PM
Quote from: Exploderwizard;785866Keep in mind when dealing with averages that they are a more useful tool when dealing with HP pools large enough to matter. Its harder to figure an average for a single roll, and that single roll on the high end can put down a soft target.

Sample size is everything. A goblin doing 3 average damage is a small comfort when the actual range is 3-8 and you have 7 hit points. :p

Yeah, you'd use maths to work out general tendencies, rather than play the game minute-by-minute.

If you think "well, on average my wizzie can survive 2 melee combat rounds, so I don't need to retreat yet", then you are a bad player, and you are about to have a very unpleasant surprise (Gobbo OHKO's the box wizzie 14% of the time).

If you wanted to, you could write out a script to run a bunch of combats... but why would you? It's a waste of time, it'll give similar results to just working out DPR's, and it won't account for actual table play.
Title: 5e Combat Simulator? (Because we all know Bob sucks at Math)
Post by: Exploderwizard on September 08, 2014, 02:58:44 PM
Quote from: Ladybird;785881If you wanted to, you could write out a script to run a bunch of combats... but why would you? It's a waste of time, it'll give similar results to just working out DPR's, and it won't account for actual table play.

 Yarp! That was kinda my point. White room theorizing doesn't do much to support actual in-game situations.
Title: 5e Combat Simulator? (Because we all know Bob sucks at Math)
Post by: Ladybird on September 08, 2014, 03:11:57 PM
Quote from: Exploderwizard;785884Yarp! That was kinda my point. White room theorizing doesn't do much to support actual in-game situations.

It depends what questions you ask, really, and what data you expect to get. Maths is a tool that can tell you some interesting things. Characters slug it out, yeah, we can work that out. Beyond that, I dunno, it's more complex.

Designers should understand the probabilities inherent in their system, it's kinda their job, but it's less important what these probabilities are than that the designer is happy with them for a given game. If we're doing a game of swashbuckling fantasy, for example, and the slightest graze is likely to kill a character, someone has fucked up.
Title: 5e Combat Simulator? (Because we all know Bob sucks at Math)
Post by: Exploderwizard on September 08, 2014, 03:25:11 PM
Quote from: Ladybird;785886If we're doing a game of swashbuckling fantasy, for example, and the slightest graze is likely to kill a character, someone has fucked up.

You mean, like cyber-swash 2020 ? :p
Title: 5e Combat Simulator? (Because we all know Bob sucks at Math)
Post by: mcbobbo on September 08, 2014, 03:28:06 PM
My ideal goal would be the ability to say 'group A will defeat group B X% of the time with Y losses'.

Like that Ultimate Warrior show...

I've seen simulators in the wild for this using other systems.
Title: 5e Combat Simulator? (Because we all know Bob sucks at Math)
Post by: Exploderwizard on September 08, 2014, 06:09:28 PM
Quote from: mcbobbo;785889My ideal goal would be the ability to say 'group A will defeat group B X% of the time with Y losses'.

Like that Ultimate Warrior show...

I've seen simulators in the wild for this using other systems.

How useful are these white room scenarios to actual gaming though?

The variety possible in a typical PC group is fairly huge. Unless your group matches the control group pretty close to on the money, the outcome may be vastly different because group A had a fighter, and your group has a paladin.

Not to mention ability scores. To be on an even keel it must be point buy. If your group rolled stats and got better or worse than that it will throw everything off.

Hit points. Same problem. Gotta assume straight average for both PCs and monsters. Someone gets good HP rolls and look out- and the formula gets fucked up.

These simulations are generally not worth the time it takes to put them together.

If you know the actual PCs and the the monsters involved then just play out a couple combats using bog standard tactics as a sort of scrimmage. At least that will use the actual stats appearing in the game instead of some theoretical model.
Title: 5e Combat Simulator? (Because we all know Bob sucks at Math)
Post by: Opaopajr on September 09, 2014, 04:36:17 AM
It all falls apart when it touches context. 5e is the same as any other here.

Have anything that can be construed as 1/2 or 3/4 cover? Then determine +2 or +5 AC, round by round, as cover can be lost or gained by opponent movement & actions.

Have any lighting beyond bright day? Then determine dim light or darkness, which lightly obscured alters sight Perception checks & heavy obscured gives you blindness (outright autofail for all sight-based checks, Disadv for every atk you make, and Adv for every atk against you).

Is there any distances in your game? etc...

At some point of complexity only experience can be a worthwhile teacher, as players are so ingenious and context is so crucial. Which is one of the best selling points about RPGs, to be honest. "Right answers" tend to not be so right or narrow in such open and dynamic systems.

edit: Also just give us the X beats Y example now, that might clear more things up, as some of us already have experience from both sides of the screen.
Title: 5e Combat Simulator? (Because we all know Bob sucks at Math)
Post by: Omega on September 09, 2014, 05:36:30 AM
Heres a partial example of how things can go off kilter very fast.

Was doing a simple combat practice with friends in prep for DMing this weekend and pitted myself as the wizard, and the gals playing a pair of fighters all level 2 vs an Ogre. We all had the same to hit chance.

Should have been fairly easy all considered...

I went down on the first round due to surprise and a solid hit.
Fighter 1 is down on round 5.
Fighter 2 survives to round 6 by the barest of fractions with a critical. Had she missed or done insufficient damage to kill the ogre, the ogre would have criticalled as well and shed have been pasted and we'd have had a TKP right there.

Had I not been taken out on round 1 I'd have missed on rounds 2 and 3. Ogre might have been down by round 5.

Just a simple shift can make a big difference.