Elementary Stacking Question

[atonal]

There may already be an answer to this somewhere, in which case I am happy to be pointed in that direction, but I was wondering which of the following elemental absorption effects stack (if any).

Shroud Weapon Tier 1 - 10% single element
Shroud Weapon Tier 2 - 15% single element
Shroud Weapon Tier 3 - 20% single element
Ring of the Djinn - 33% electrical
Primal prefix - 10% all elements
Shiradi elemental absorption (Tier 4) 5/10/15% all elements
Sentinel block energy(Tier 3) 10/20/30% all elements
Any other I missed

Looking to see what the theoretical max is (Stormreaver tanking anyone?) and which I can feasibly stack onto a build. Was wondering if it stacks similarly to heal amp (different values stack). Also interested in the mechanics of how they stack: multiplicative or additive

Thanks all in advance

[gphysalis]

I believe that elemental absorb stacks like healing amp:

Different values on items stack, and everything is multiplied.

Cannith crafting can make elemental absorb items, and the non-epic ring of the djinn has 20% absorb

If you twist in energy sheath (from the draconic destiny) you can get 50% absorb. (This is similar to fire shield, but you pick the element when spending ranks)

[Kinerd]

I think this thread will help you a great deal.

[Fafnir]

I believe that elemental absorb stacks like healing amp:

Different values on items stack, and everything is multiplied.

Cannith crafting can make elemental absorb items, and the non-epic ring of the djinn has 20% absorb

If you twist in energy sheath (from the draconic destiny) you can get 50% absorb. (This is similar to fire shield, but you pick the element when spending ranks)

This is a bit of a necro, but was a useful thread on the topic.

The tester incurred 20d6 fire damage and recorded maximums. 20d6 should have a min of 20, a max of 120 and an average of 70. The recorded maximum however was 76 if I interpret the way he described the test results properly.

Base average damage 70; max 120

Apply resist

Ave 70 damage
less 45 total resists 25 damage; max 75 damage

Apply absorption

Greaves 33%: 25 * (1-33%) = 17 dmg; or 50 max

Sickle 17 x (1-10%) x (1-15%) x (1-20%) = 10 average; or 31 max

Apply fireshield cold

Shield 50% = 10 x (1-50%) = 5; or 15 max

Roughly shows this up. If resists were additive, then 33% + 45% + 50% would give immunity, which it doesn't. Progressively applied, this test should show (1-33%)*(1-10%)*(1-15%)*(1-20%)*(1-50%) = 20% damage taken, applied after resistance effect is deducted.