When using traps, blades, shields, and other damage modifiers, just how is the final modifier totaled? It seems that a shield overwrites the traps and blades, reducing the damage far below the "total" modifier should be.
Add (or subtract) each modifier to 100%, then multiply them all together times the base damage.
Example: +10% domage boost from gear -> 110% +30% blade -> 130% -25% weakness -> 75% If base damage is 100, the result will be 100 x 1.10 x 1.30 x 0.75 = 107 points. So a -25% weakness cancels a little bit more than a +30% blade adds on.
Another: +30% blade -> 130% +40% trap -> 140% -50% tower shield -> 50% base damage 100, result 100 x 1.30 x 1.40 x 0.50 = 91 points So a tower shield cancels a bit more than two regular buffs.
Finally: +20% gear boost (not uncommon at master levels) -> 120% +40% school blade -> 140% +25% balance blade - > 125% +25% global boost (such as balefrost) -> 125% +30% trap -> 130% -70% shield -> 30% Base damage 100 results in: 100 x 1.20 x 1.40 x 1.25 x 1.25 x 1.30 x 0.30 = 102 points damage. Meaning a single 70% shield will cancel out the effects of about FIVE buffs. Without the shield, that 100 point spell with five buffs would have done 341 points damage! Moral: break the shield first even if you have to sacrifice a couple of your buffs to do it. Even if you then only have two or three buffs left to apply, you will still get better damage than if you leave the shield in place.