Attack rolls

Mirrimon

I am confused on where the modifiers for the attack rolls is from. When you turn on attack rolls in the feedback you get a format like this
Attack Roll 18 + 10 = 28 : Hit

How does the game get that bonus (10 in the example.)

Some confusing situations:
+3 dagger with +3 from str. No other bonuses to hit vs ac -7 fullplate +1 sheild +2
the bonus is +7
same +3 dagger with +3 from str and no other bonuses vs ac-1 studded leather armor +3
the bonus is +5 ? ?
If i take the +3 studded leather off, the bonus jumps to +6 (the same i get against my robe users)
If i take the +1 fullplate off the bonus jumps to +10 (?!)

same attack vs a fighter using non magic fullplate and total ac -4 gets a +3 bonus

Any ideas?

Pibaro

Check the description of the armour, it should state a bonus/malus versus piercing/slashing ecc. attack.

Mirrimon

The leather armor is ac4(2vslash 3vpierce) So losing one bonus from the piercing dagger attack makes sense. But the fullplate is ac0 (-4vs slash, -3 vs pierce) so the bonus should drop to 3, not rise to 7.

sarevok57

this is something that was implemented when the new version of the infinity engine came out eons ago, what the game does is this: you have your base thac0, say its 10, then you have thac0, say its 3, so what will happen is every time you attack someone, it will have a +7 to hit ( 10 - 3 = 7) and then as @Mirrimon said, all armors have modifiers to make that "bonus" lower or higher ( the reality is, its not really a bonus per se) see in the original vanilla bg1 they didn't do it that way, so seeing +0 was very common, and it was much easier to know what modifiers were being applied ( racial enemy, invisible would give a +4) so you would know much easier what the real bonuses were, so basically now if you want to calculate what real bonus you are getting you have to go from the base thac0 and not the actual thac0, for example, lets have the above where the character has 10 base thac0, if they are getting +5 in the game window, then their thac0 is 5 against that enemy, but if they switch over to another enemy and are getting +10, then their thac0 is 0 against that enemy, it can be a little confusing at first, but will eventually make sense, I liked how they did it in vanilla bg1 better, but I don't fret on it too much, basically once your thac0 hits -10 or lower, you aren't going to miss anything anyway

Mirrimon

Yeah that is what I came up with in my tests thought, the problem was that I had this unknown bonus to account for against my -7ac cleric. Turns out it was the ranged weapon in melee penalty. (Making the bonus 7 instead of 3 as I had thought it should be)

sarevok57

ah I see