Astrichthyes wrote:The only exception I see for this is when you use a low-base-AR weapon that scales very poorly on the stat you have invested in (ex BoM on a Str build).
Nope. Scaling works off of base AR. Here's the formula (without gems):
Total AR for a given damage type = Base AR + Base AR * (Scaling Coefficient1/100) * Scaling Saturation1 + Base AR * (Scaling Coefficient2/100) * Scaling Saturation2
Coefficient is the number that the various letter grades stand for.
Saturation is the % of total damage you're getting from a scaling stat. I.E., at 0 Strength, you'd have 0% scaling saturation, while at 99 Strength you'd have 100%.
Coefficient1/Saturation1 is for the first scaling stat, and Coefficient2/Saturation2 is for the second scaling stat, assuming there is one.
So basically, a scaling coefficient gives you a percentage of your base damage as a bonus. E.G. Kirkhammer has a 100 Str scaling coefficient, which means if you have 99 strength, you get +100% base damage (in this case, +210).
When you add a +% damage gems, it looks like this:
Total AR for a given damage type = (Base AR + Base AR * (Scaling Coefficient1/100) * Scaling Saturation1 + Base AR * (Scaling Coefficient2/100) * Scaling Saturation2) * (1+Gem1%) * (1+Gem2%) * (1+Gem3%)
Now I haven't seen a whole lot of testing on +scaling gems, but based on my understanding, they work like so:
Total AR for a given damage type = Base AR + Base AR * (Scaling Coefficient1+Gem1+Gem2+Gem3/100) * Scaling Saturation1 + Base AR * (Scaling Coefficient2/100) * Scaling Saturation2
Basically, +% damage effectively gives "+% ALL AR of a given type". If you have 210 base AR + 210 bonus AR, you get +27.2% of 420 AR. Meanwhile, by increasing the scaling of a weapon, you are effectively giving your weapon "+x% BASE AR of a given type, and only if you have 99 in the stat you are applying a scaling gem to." So if you have 99 Strength and have 210 + 210 AR on your Kirkhammer, applying a +scaling gem means you get +27.2% of 210, rather than of 420. So in order for a +scaling gem to compete with a +%damage gem, you need:
-0 bonus AR from scaling from any stat for the given damage type
on on the weapon you're putting it on.
-99 in the stat that the gem increases the scaling of.
And even if this were possible, you run into what Astrichthyes pointed out, which is that +scaling stacks additively, while +% damage stacks multiplicatively! Even if you had a theoretical weapon with 0 scaling in any physical stats, and gave it a +scaling gem, it would merely be on-par
with +% damage gems if you had only 1 slot, and then fall behind as you unlocked more slots!
It's possible that I'm completely misunderstanding the way +scaling gems work, but I've seen no evidence that they work any differently than how I illustrated above. I am fairly sure that +scaling gems are Strictly Worse
than +% damage gems and should never be used as long as you have access to equally powerful +% damage gems.