A Land Far Away

If you have medium base attack bonus you get a +3 bab every four levels. So like a rouge would get nothing a lvl 1, +1 at lvls 3-4 and then nothing again at 5.

The problem occurs if you have multiple classes with medium attack bonus. For every extra class a character has with medium attack bonus they will lose 1 BAB unless one of the classes they have has for levels or a multiple of four levels.

For example: A rouge lvl 3 gets a plus 2 BAB. A rouge 1/monk 1/cleric 1 gets no BAB because every lvl they have taken is the first lvl of a medium BAB class which grants no bonus.

It isn't something that only hurts lvl dippers either. A cleric 4/ thief 3 takes no penalty because he has four cleric lvls. A cleric 5/thief 2 loses 1 BAB.

It also effects prcs which are considered another class. A straight cleric takes no penalty, but a cleric 6/doom guide 2 would get a neg 1. A monk 1/cleric 6/doom guide 1 would get a negative 2 BAB penalty.

This can be worked around by going cleric 8 before taking doom guide lvls but that should not be needed. The way it should work is: number of high BAB lvls plus number of medium BAB lvls minus 1/4 the number of medium BAB lvls plus number of low BAB lvls minus 1/2 the number of low BAB lvls.

Remember that base attack bonus is also more important then regular attack bonus because it determines your characters number of attacks per round. It can also be a requirement for some prcs

One of the unfortunate side effects of multiclassing with two "average" BAB classes. Its just the cost you pay. Seeing as you add the full level 1 saves to the class in return, the trade off often doesn't end up being too awful.

That isn't the way it is supposed to work in dnd 3.5.

Also players who pay attention to the 4 level rule take no penalty but also still get to add lvl one saves. This doesn't make any sense.

The trade actually really awful when it costs you an extra attack per round which it will when you get to that lvl where you would start getting two attacks.

That is the way it is supposed to be in 3.5.

In my pnp games, we house rule to allow two average BAB classes to stack together as if one class with their BAB, but that is a house rule. Canon 3.5, you lose that point of BAB as you go.

fractional BAB is an optional rule from unearthed arcana. it's not core D&D

Well I like the house rule your pnp group plays with a lot better and I think most of our community would agree if we could put it to a vote. The other way just doesn't make a lot of sense to me.

The worst is with PRC's. You can't take one at 5 taking advantage of the 4 rule. You could wait until 9, but how many pcs make it until 9. If you take one at 6 or 7 which is usually the first opp. it is gonna delay getting two attacks from lvl 8 to 9. Considering how long it takes to go from 8 to 9 that is a huge drawback.

Most every prc already has some drawbacks. Usually a feat you might not have chosen that is required. Adding a loss of BAB to this seems overkill. I think we should at least consider making it possible to take some of those prcs at 5 rather then 6 or 7 so the 4 rule can be considered.

Not technically feasible.

SetBaseAttackBonus() does not work on players, some system of enforcing edits from DMs with the console would be inconsistent and unwieldly, and developing a NWNx4 plugin exclusively for the sake of adjusting BAB for a specific breed of multiclassers is a strange request at best (while not being garaunteed to work). Other scripted solutions would either put attacks on the haste queue (terrible representation of higher BAB; see also: divine power) or trying to argue some sort of inconsistently-stacking system of attack bonus effects applied as part of client enter (which wouldn't provide additional attacks while requiring at least some special handling to make it play nice with spellcasting).

Four-level PrCs are "possible," but would require a signficant reworking of our core rules. If you truly wish to pursue such, the best place to begin would be in seeking the sanction of the DMA, as no PrC is worth working on if the DMA would rule that no one gets approved for it.

I figured this was likely the case given how core this mechanic is to the system. Thank you for the technical feedback.