Opposed Attack and Defence Rolls

[skywalker]

This is something that I raised on Blue Rose forums but got no response.

I have been asked by my gaming group to consider using opposed attack and defence rolls, being a riff on the current True 20 system.

Essentially, you roll your attack, your opponent rolls defence. The random part of damage is determined by the difference between the 2 scores.

Here is how I would see it working:

1. Attack value = d20 + combat bonus + Dex.
2. Defence = d20 + combat bonus + Dex.
3. Damage = weapon bonus + Str.
4. Toughness = armour bonus + Con.

If you successfully hit i.e. Attack > Defence, then Damage is calculated as follows (Attack - Defence) + (Damage - Toughness):

0-4 = Hurt.
5-9 = Wounded.
10-14 = Disabled.
15-19 = Dying.
20+ = Dead.

This is also quite nice in that Conviction can be spent on a Defence roll. I find that spending a Conviction on Toughness to avoid being hurt doesn't feel as "cool" as spending it on the Defence roll to avoid being hit.

A Touch Attack is an attack which ignores the Toughness bonus from Armour.

An attack roll which lands in the “critical threat range” is considered a Touch Attack and ignores the Toughness bonus from Armour. Criticals as such are no longer needed as high rolls do more damage.

BTW for those who like figures, here is the % of results based on equal Attack and Defence (roughly).

New system
None - 50%
Hurt - 22%
Wounded - 15%
Disabled - 9%
Dying - 4%
Dead - 1%

Old system
None - 50%
Hurt - 12.5%
Wounded - 12.5%
Disabled - 12.5%
Dying - 12.5%
Dead - 0%

The result is that the chance to hurt is about the same. However, lesser wounds are more likely than grevious wounds (though in either case these are still possible).

[Dork Elf]

I like it on paper, yet it sounds really lethal in practice, not to mention a bit slower. I say "lethal" because with Defence not static, a low defence roll could make someone take SO much more damage. It kinda makes the roll the primary damage criteria and Str/weapon damage secondary, which is fine if you like that. I would use this system in a really grim, realistic setting but not in a heroic one.

Your criticals are serious stuff. The only thing is, if you are attacking someone without armor on and they roll high defense as well, you may end up doing not much more damage than you would at all. Just mentioning that for enemies with no armor but super-high Con, ect.

I like it, but as I said it wouldn't be perfect for every seeting imo. I like the idea of a better attack roll causing more damage, but I am unsure of how this could unbalance STR in relation to DEX since DEX effectively causes more damage just like STR does in this system. KNow what I'm sayin?

[bushido11]

Well, I was going to suggest to simply take the Power Attack feat, but after looking through the book, it's not there. I wonder why.

[reverend keith]

This is something that I raised on Blue Rose forums but got no response.

I didn't say anything, because I wouldn't use the system. It encourages dishing out lethal damage far too randomly for my tastes.

Essentially, you roll your attack, your opponent rolls defence. The random part of damage is determined by the difference between the 2 scores.
..
Damage is calculated as follows (Attack - Defence) + (Damage - Toughness)

Assuming that you are keeping the DC for damage saves at (15 + damage), then I'd never use it.

Given that we are talking about comparing the results of two twenty sided dice, there is going to be a lot of variability between the contested rolls. Adding that difference directly to the toughness save DC is going to mean that fatal damage will be dished out relatively randomly.

In comparison, Power Attack is too powerful in Blue Rose (and was stripped out of True20) because a +5 bump to damage is extremely lethal. Now imagine using your system and rolling a 5 for defense while your opponent scores a 15. +10 to damage transcends brutal. Now imagine rolling a 1 and a 20.

The result is that the chance to hurt is about the same. However, lesser wounds are more likely than grevious wounds (though in either case these are still possible).

This is only accurate if everyone rolls roughly the same on a d20. There is a lot of variability in two d20s...

[reverend keith]

Well, I was going to suggest to simply take the Power Attack feat, but after looking through the book, it's not there. I wonder why.

Because it's extremely lethal in a damage save system.

It was in Blue Rose, but IMO, it was wisely stripped from True20.

[skywalker]

I like it, but as I said it wouldn't be perfect for every seeting imo. I like the idea of a better attack roll causing more damage, but I am unsure of how this could unbalance STR in relation to DEX since DEX effectively causes more damage just like STR does in this system. KNow what I'm sayin?

Yep. It certainly gives more weight to Dex and the Attack roll. Maybe I will drop the Critical Effect altogether given that a high roll causes more damage anyway.

As to the comments about the system being more lethal, I am not so sure. The new system does mean that there is the "potential" to do more damage due to the differences between the 2 dice i.e. a mook could roll really well and get a good hit against a seasoned warrior rolling badly. However, this is something that exists in a form in True 20 at the moment anyway with the Toughness save. In True 20, Conviction is used to reduce the randomness of damage and this would continue with the new system (more so to an extent as the Conviction applies to the Defence).

However, on the whole, the system is actually less randomly lethal. There is roughly the same chance to hit. "Hurts" and "Wounded" are slightly more common but serious injuries are less common (considerably less even).

[FickleGM]

This sort of thing crossed my mind as well, but I decided against it for two reasons. First, while it does reward a good "hit", it does appear that the randomness of it would increase the number of freak knockouts (it may average out in the long run, but is too difficult to account for). Second, it appears to me that this brings armor back into the hit vs. miss equation that I didn't like in d20.

I just thought of a question, what if you roll 1 higher on defense but my damage is 7 higher than your toughness (greataxe and +4 str vs. leather armor and +1 con)? If I read correctly, you would be wounded.

Anyway, I would allow my players to roll their defense if they wanted to (I know, it's an extra die roll), but would not take the attack results into consideration when making the toughness roll. This would allow for the conviction point reroll to avoid being hit (but, would use up the conviction usage for that round and negate any attempt to reroll toughness).

Anyway, just my two cents on the topic.

[skywalker]

Assuming that you are keeping the DC for damage saves at (15 + damage), then I'd never use it.

No. I don't think you quite understand what I am suggesting. Each PC still only rolls one dice but the defender rolls defence instead of toughness.

The difference between the 2 scores and the adjustment for armour and damage produce a number that is applied to the existing failed Toughness chart.

For example:

Anno, a 12th level Expert assasin attacks a 5th level Knight Sir Del.

Anno has a Combat bonus of +9 and a Dex of +2. He has a Str of -1 and is using a dagger with a damage of +1.

Del has a Combat bonus of +5 and a Dex of +1. He has a Con of +3 and is wearing a Breastplate with toughness of +5.

Anno rolls a 16 to attack, adding Combat bonus and Dex like normal this results in a score of 27.

Del rolls a 8 to defend, adding Combat bonus and Dex this results in a score of 14.

27 is greater than 14 so the attack hits by 13. Anno's base damage is 13. He adds his Str (-1) and Knife (+1) to get 13 and then subtracts Del's Con (+3) and Armour (+5) to get a final score of 5.

Looking at the chart (the same amounts for failed Toughness saves) this is a Wounded result.

Del decides he doesn't want to get Wounded so he spends a conviction and rolls a 4 (increased to 14). This reduces the base damage of the attack to 7 and the final result to 0 (meaning no damage).

Again, in practise though the potential for a higher range of damage increases, the overall lethality decreases. This makes Conviction more effective (need to use it less often and it will avoid bigger hits better) and in a sense make the PCs more robust.

[skywalker]

This sort of thing crossed my mind as well, but I decided against it for two reasons. First, while it does reward a good "hit", it does appear that the randomness of it would increase the number of freak knockouts (it may average out in the long run, but is too difficult to account for). Second, it appears to me that this brings armor back into the hit vs. miss equation that I didn't like in d20.

Not really. It will mean that a lower level PC will now have a glimmer of getting a "big hit" that they couldn't before but on the whole the chance of a "big hit" reduces dramatically. The use of Conviction already covers the first part of this equation in True 20 and would be even better designed to do so under this alternate system.

Second, it appears to me that this brings armor back into the hit vs. miss equation that I didn't like in d20.

I just thought of a question, what if you roll 1 higher on defense but my damage is 7 higher than your toughness (greataxe and +4 str vs. leather armor and +1 con)? If I read correctly, you would be wounded.

No it doesn't. You can take this process one step further as they did in WoD by adding all factors together at the start. However, by requiring that Attack must exceed Defence to score a hit before applying Damage and Toughness, armour doesn't make you harder to hit.

[skywalker]

I didn't say anything, because I wouldn't use the system. It encourages dishing out lethal damage far too randomly for my tastes.

Not to belabor the point but this is an interesting point. Maybe I should explain some background to how my group got to suggesting this house rule.

Our experience with BR and True 20 is that after being hit, the Toughness roll felt too random and in some ways lethal. Once you are hit, you commonly have the same chance of rolling a Disabled as a Wounded as a Hurt as all wound conditions are exactly 5 possible results on a d20. This bothered me a little and the group chewed trhough Conviction at a rapid rate.

This new system seems more random on the surface. However, statistically the chance to hit is similar. All things being equal this alternative will produce numbers in a similar range as those is the normal system. Also the chance for "big hits" decreases dramatically. Check out the probabilities above. As Conviction is used to avoid the "big hits" this also means that Conviction needs to be used less and as it impacts on the quality of the hit itself seems to have a more direct impact.

Look at things statistically again (my last figures were a little out):

All things being equal in True 20 you have roughly a 50% to hit. If you hit, you have a 25% of being OK, 25% of being hurt, 25% of being wounded and 25% of being disabled.

In this alternative, you have roughly 50% of being hit. If you hit, you have a 45% of being OK, 32.5% of being hurt, 20% of being wounded and 7.5% of being disabled. (NB: in order to get a direct comparison with True 20 I have added 5 to Toughness)

More thoughts appreciated. Are we off our rockers?

[reverend keith]

However, on the whole, the system is actually less randomly lethal.

Only if you assume that people have roughly the same bonuses to hit and or roll the same numbers on two d20s.

There is roughly the same chance to hit.

My problem isn't the chance to hit. It's increasing the amount of damage you do due to the "degrees of success" that you roll on your
combat roll.

The tenth level expert is going to lose that contest to a tenth level warrior more often than not, and watch the warrior dish out +3 damage *on average* to the vastly outgunned expert. Switching out the expert with an adept, and you'll see the adept take +5 damage on the average hit.

That, IMO, seriously magnifies the True20 combat deathspiral for non-warriors.

[reverend keith]

Anno rolls a 16 to attack, adding Combat bonus and Dex like normal this results in a score of 27.

Del rolls a 8 to defend, adding Combat bonus and Dex this results in a score of 14.

27 is greater than 14 so the attack hits by 13. Anno's base damage is 13.

Apparently I read this wrong. So the degrees of success don't add to damage, but rather they use the chart listed above. Hmmm... Let me think about this.

[skywalker]

That, IMO, seriously magnifies the True20 combat deathspiral for non-warriors.

Good point. This will certainly increase the gap between Warriors and other Roles. However, other Roles have the chance to do greater damage to those Warriors than before.

Hmmm...

[skywalker]

Apparently I read this wrong. So the degrees of success don't add to damage, but rather they use the chart listed above. Hmmm... Let me think about this.

Yes, I am not using the standard True 20 Toughness roll. This system has just two rolls one for Attack and the other for Defence. You no longer roll Toughness. This system is similar to quite a few other systems such as Silhouette (DP9), Synergy (Blue Planet), WoD, Earthdawn and others

In this alternate system, the degree of success will increase the damage done but not as drastically as it would be to use the existing True 20 system and simply add to the damage bonus.

This alternate system calculates damage by flipping the current Toughness failure chart so not to read 'failed by x' but simply use x being the damage (Margin of Success on the hit + Damage - Toughness). When you work that out then:

0-4 - Hurt
5-9 - Wounded
10-14 - Disabled
15-19 - Dying
20+ - Dead

[Warbringer]

I like it.

This does something that is missing in most roleplaying simulations; the amount of damage that you will take in a fight is really dependent on the difference of skill levels, not the damage of a weapon.

Think about Riddick kills a guy with a tea cup, or how a mook with a machine gun misses the hero, of if he hits does little damage.

Yes, it is more leathal, but conviction stops "freak" results of chance most of the time.

On a different note, I'm really leaning towards True20 using 2d10s rather than 1 d20.