So the CMB rules specify a modified size bonus.
They also states "Add any bonuses (And presumably penalties) you currently have on attack rolls due to spells, feats, and other effects."
My question is, does the Size bonus to CMB (say from enlarge person) negate, or REPLACE the size penalty to hit?
Negate.
They replace. You do not have the normal size modifiers to hit on CMB/CMD. Regarding CMB, the PRD says:
When you attempt to perform a combat maneuver, make an attack roll and add your CMB in place of your normal attack bonus. Add any bonuses you currently have on attack rolls due to spells, feats, and other effects. These bonuses must be applicable to the weapon or attack used to perform the maneuver.
Regarding CMD:
Some feats and abilities grant a bonus to your CMD when resisting specific maneuvers. A creature can also add any circumstance, deflection, dodge, insight, luck, morale, profane, and sacred bonuses to AC to its CMD. Any penalties to a creature's AC also apply to its CMD.
The section abut CMB talks about "bonuses", so it's pretty vague, but it seems like if normal size modifiers were in there, they would have mentioned it. The section about CMD specifically states which bonus types are added, and size isn't among them. If the normal size modifiers should be added, only negative ones would be, as per the "Any penalties to a creature's AC also apply to its CMD".
And regardless, just look at a random monster in the Bestiary, and you will see that none of them have negative modifiers for being large. All follow the "BAB + str mod + size mod (+4 for grab)"-formula. Large creatures have huge CMB/CMDs.
Even if the wording was unclear, the bestiary does make it abundantly clear that being Large means +1 CMB from the CMB bonus replacing the attack penalty, not +0 from a CMB bonus cancelling out an attack penalty.
The goblin and other small races have it as negates by the math. I thought it was replace until I did some reverse engineering.
The goblin and other small races have it as negates by the math. I thought it was replace until I did some reverse engineering.
I think the choice of negate/replace is a bit misleading, as I interpret "negate" as "both modifiers are added, and they cancel out" and replace as "only the special modifier in the CMB/CMD definition is added". The Goblin in the Bestiary clearly follows the "replace"-idea, so I think we are talking past each other.
The Goblin has CMB +0 and CMD 12
CMB: +1 BAB +0 str -1 size = +0
CMD: 10 +1 BAB +0 str +2 dex -1 size = 12
Here we clearly see that only the negative "special" CM-modifier is added.
The size modifier to Attack rolls is not factored in as a modifier to CMB/CMD.
The text that makes this clear reads as follows (bold emphasis mine):
When you attempt to perform a combat maneuver, make an attack roll and add your CMB in place of your normal attack bonus.
Referencing the combat section, we find "attack bonus" defined as follows (bold emphasis mine):
Your attack bonus with a melee weapon is:
Base attack bonus + Strength modifier + size modifier
Your attack bonus with a ranged weapon is:
Base attack bonus + Dexterity modifier + size modifier + range penalty
As we can see, the size modifier to attacks is included in the "attack bonus" which is replaced entirely by the "CMB" and is not in the list of bonuses that applies to CMD.
The goblin and other small races have it as negates by the math. I thought it was replace until I did some reverse engineering.I think the choice of negate/replace is a bit misleading, as I interpret "negate" as "both modifiers are added, and they cancel out" and replace as "only the special modifier in the CMB/CMD definition is added". The Goblin in the Bestiary clearly follows the "replace"-idea, so I think we are talking past each other.
** spoiler omitted **
I was counting that BAB as 0 for some reason. oops.