Request: Combat Mechanics Advise

Quick question, are you looking to use one of those mechanics?

Anyways, I like D6's, just because their easier to use, and I have also tried D12's with people and nobody really likes them. (Don't know why though)

What you could do is use two d6's and roll, after it their rolled you add those two up, and add any modifications. (something like +2 if your attacker, or +3 with this weapon etc...)

Hope that helps,
-Justin

I like d6. You don't have to do just 2d6 with modifiers. You could say: reroll all 1s..or reroll all 6s. or whatever as a modifier.

i used the D10 vs Target # system for a miniatures strategy game awhile back and the mechanics just fell into place. It was so easy to estimate odds. Seems like D20 vs Target # would be the same way. I'd avoid d6. I wanted to use d6's in the original idea for the game, but the small array of #'s limited the variation of some of the pieces.

Nothing like posting a "figure out the probabilities" post without following up with some hints! Sorry about that.

Short of doing the math (blech) or writing a program to run the numbers (which is what I do), my suggestion for figuring out probabilities is straightforward: count the possibilities with a spreadsheet like Excel.

Here's how:
1) Make your first column all possible die rolls for die "a"
2) Make your rows all possible die rolls for die "b"
3) Write the "value" of the combined roll in each of the cells of the resulting grid. For example, if you're doing "add the dice" or "greater of", or whatever.
4) Count the hits
Steps 2 through 4 can all be done with macros to reduce the amount of typing you have to do.

Here's an ASCII example of what I'm talking about (hopefully it will turn out ok):
d2
d1 1 2 3 4
-- -------------
1 | 2 3 4 5
2 | 3 4 5 6
3 | 4 5 6 7
4 | 5 6 7 8

What are the odds of rolling greater than a 5 on 2 d4? Just count in the table. Six numbers are higher than 5 and there are 16 possible combinations, so the answer is 6 out of 16 or 37.5%

Just to toss out something different (after rereading my post I start rambling as usual, sorry :),

A different option
Have you considered some type of card or tile mechanic for combat? First it if very easy to modify (add/remove) outcomes when using cards/tiles.

Since I do not know what the rest of your game mechanics/rules might include, you could create pool of cards that players could jointly use. Drawing from the deck to determine combat. For instance, instead of rolling 1d10, you have a deck of cards, cards contain a single value from 1 to 10. Players draw during combat... so on. This might give you more control over the probabilities/outcomes.

You could also take this same concept and have each player build up their own combat deck. So this might allow variation of possible outcomes, for different players. Maybe I could have cards with value 2 - 8, but you might have a deck with card values 1 - 10. Maybe the cards contained in the deck can be based on different skill/abilities.

Some comments about your listed options
As for your 4 listed options, I agree with OrlandoPat and you should look at your probability and see what dice (if you want to use dice) mechanic fits best.

I would also consider all the various ways to attack in your game. There may be need for flexibility in combat. For example, if you can attack in combat and your USE a two handed sword, does this effect the roll being made? If you and I are dueling in combat, do you and I roll the same number of dice, are the value ranges the same?

Also, I noticed you put D20+MOD, you might think about the other 3 options with +MOD also. #Atack Dice + MOD vs #Defense Dice + MOD.

To me the D20, if yo uare targetting RPGers, is the most familar path to go down, but you may not have other ppl ineterested.

#d6 vs #d6 can be hard to work with if you dont work work from the probabilities direction. This was one of the harder areas to work on in the RPG I helped create (which is d6 based).

#d6 vs Target, again you need to work on probabilities so that your Target value is reasonable/possible for players rolling d6.

#attack dice vs #defense dice might allow you more flexibility, since the number if dice involve can be easily changes, but again you need to validate your combat values. Basically you ned to make sure that players rolling 2d6, dont end up against targets rolling 12d6. Not sure if you would get to this point, but you have to keep it in mind. This is also true for #d6 vs Target value. You need to make sure that during gameplay players dont get to a point where they cant succeed rolling their 2d6, vs Target value of 13.

Sorry enough rambling..... not sure I helped at all, but I had fun rambling :)

Well, there's been a lot of talk about probabilities here, but I think there are many issues to consider that are more important than mere probabilities. Your choice of combat system should be more heavily influenced by the role that combat plays in your game. Some questions to consider:

How frequently do combats occur? If every turn will see twenty combats across the board, you need a resolution system that's as quick and painless as possible.

Do players work to get opportunities for combat, or do combat events just pop up at random? If players are working to get combat opportunities (hunting down monsters, collecting weapons and combat forces, etc.) then combat should probably be a big event. In this case, you should not have a quick resolution system, because it would be an anticlimax. Buckets of dice, multiple rounds, decks of cards, etc. would be in order.

How big a part does combat play in the game? Is it what the game's really about, or is it one detail of some bigger picture? If combat is supposed to be one of the central elements of fun, then you might want a fairly elaborate combat system that generates a colorful description of what happened. Critical hits, thrusts and parries, loss of footing, etc. all might be simulated in some way.

Is combat a distinct type of event in the game, or is it one of several types of obsticals that are thrown at a player? In the latter case, you might want a combat system that's consistent with your methods of handling other types of obsticals. For example, in Age of Exploration (by TimJim Games), every event -- be it combat, negotiations with natives, navigating through the Amazon, or what-have-you -- is resolved by comparing a modified d6 die roll to one of your expedition's attribute values. Different attribute values are used for different types of obsticals, but it's always the same basic mechanic.

How important are contextual factors in combat? Does terrain play a role? Surprize? Weather? If there are only a couple such factors, you can get away with some special rule for each. If there are many, you need some generalized mechanic for handling them, such as the die-roll-modifiers that are loaded into virtually every combat in a war game.
Compared with these issues and others like them, I don't think the probabilities are so critical, particularly since you're not designing a simulation game. I suspect you only need to ensure that "big and nasty probably beats small and weak". Beyond that, you need to come up with a system that's sufficiently quick/substantial/colorful/consistent/flexible/etc. to be fun in the context of your game.

-- Matt
[/]