d20 Rules Variant

Applies to Dungeons & Dragons, 3rd Edition

Standard Rule
When a player character multiclasses, the modifiers they receive to base attack bonus and saving throw bonuses are computed individually for each class, then added. This leads to interesting minmaxing effects, since fractional bonuses are dropped prior to aggregation. The computations per bonus are:

BABclass = floor(class level * (cond((strong,1),(medium,0.75),(weak,0.5)))
BAB = SUMclasses BABclass

Saveclass = cond((strong,2),(weak,0))+ floor(class level * (cond((strong,0.5),(weak,/3)))
Save = SUMclasses Saveclass

Variant Rule
Whenever a player gains a level, their fractional bonus is added to their current bonus, and, if that pushes them over an integer value, they gain the effect. In addition, any class with a strong Saving Throw gains the relevant Virtual Feat (Lightning Reflexes, Iron Will, Great Fortitude), all of which are modified to:

Gain +2 class bonus to your relevant saving throw. If you take this feat again, this modifier is only +1, but stacks.

The new computations are:

BAB = floor(1.0*(strong class levels) + 0.75*(medium class levels) + 0.5*(weak class levels))

Save = Feat modifier + floor((strong class levels)/2 + (weak class levels)/3)