does 10% chance of x damage get multiplied by skill's base weapon damage

I just tried to check and it seems it would but i’m not sure.

for example mythical bonesnap gravel has “10% Chance of 2450 Internal Trauma over 5 Seconds”, would a 500% weapon damage 3rd cadence hit deal an additional 12250 internal trauma over 5 sec (10% of times), without other physical bonuses?

No. Those skills are stand alone skills. They may include weapon damage%, but that is only your weapon damage, which include buffs. Cadence is a stand alone skill. Those procs will happen when you use Cadence, but the damage listed, is the damage done on the proc.

He asked not about secondary skill provided by item, but about BASE item stat provided by item.

The correct answer:
That 10% chance will work for ANY attack or skill with %Weapon Damage on it, because it adds flat damage (in this case, Internal Trauma). If you have %chance for non-weapon effect (for example, Mythical Blazethread Sash has 10% chance for +1400% burn damage), it will work for everything.

ok, i understood it will work, but will it multiply that damage amount by the skill’s %weapon damage?

Here is the item:

So it’s not an (on hit/crit) type skill, but that doesn’t really change anything. When he hits a mob, or uses a skill with Weapon damage%, that 10% chance does the raw damage listed, and does not include any weapon damage. The weapon damage was applied when you hit the mob, or on the skill which used your weapon. That 10% chance is an additional damage bonus.

And if the skill that uses the weapon only uses 50% of the weapon damage, that damage is also reduced to 50%.

Then I don’t see why if the skill that uses the weapon uses 500% of the weapon damage (as i wrote) that damage wouldn’t be augmented to 500%…

anyway from the game guide:

% Weapon Damage

As you discover new abilities, you will eventually stumble upon skills that deal % Weapon Damage. What this means is that the skill takes the damage and effects you would deal on a regular attack and multiplies it by the displayed %. This includes things such as life steal, bonus magical damage and chance on attack item skills.

Example: 125% Weapon Damage on a skill will take your basic attack and multiply it by x1.25

it doesn’t say anything about chance on attack modifiers or flat damage, only chance on attack skills

Sure, it’s a flat amount, added to your Weapon Damage. Any skill, that has “%Weapon Damage”, will multiply your total Weapon Damage (including flat bonus that might be added with 10% chance) by given percentage.

It will be augmented to 500%. For example, if you use lvl26 Cadence, you will apply 5 times stronger DoT, compared to default attack.

Side effects, that applied by %Weapon damage (such as “life steal”, resist reduction, damage reduction, etc) are capped at 100% effectiveness, though. Even if your skill deals 500% Weapon Damage, those effects will apply with 100% effectivenes, due to cap (it’s a balance issue, otherside skills with high %Weapon Damage would apply too powerful side effects).

oh, thank you! also nice to know you get the same lifesteal from cadence and, say, savagery

Another note about weapon damage% that is below 100%. ADCTH has an additional penalty.

If a weapon has 10% ADCTH, and the skill you use has 50% weapon damage, the ADCTH on the weapon will changed to 50% of the original value, making it 5% ADCTH and you still only get to convert based on 50% of the damage.

I don’t understand why they decided to doubly reduce the effect of ADCTH, but they did.

Because it would make lower weapon damage skills abuse the full adcth and if it increased above 100% weapon damage, it would be broken.