What I've discovered so far:
- calc4 determines the % of weapon damage converted. However, a hidden divisor of 8 is applied when converting to poison: actual poison bit rate (damage per frame) is (weapon damage) x (conversion % in calc4) ÷ 8.
- If weapon damage is converted to poison, the poison length is set to whatever value you provide in ELen. However, there seems to be a hardcoded minimum length of 50 frames. If you leave ELen blank or set it to a value less than 50, it is ignored.
- If you equip multiple items that provide poison damage, total poison bit rate is sum of individual poison bit rates, and total poison length is (sum of poison lengths) ÷ (# of items). This corroborates what is known on how Poison Dagger works.
- Any poison damage set using the EMin / EMax and EMinLev# / EMaxLev# columns is added to the converted poison bit rate.
- Since Strength bonuses increase dagger damage, they also increase converted poison damage.
- Similar to most melee skills, calc1 provides a +% Damage bonus. This also affects the converted poison damage.
- Deadly Strike also doubles converted poison damage
- Crushing Blow does not affect converted poison damage†
- +% Poison Skill Damage does not affect converted poison damage. On the other hand...
- -% Enemy Poison Resistance affects converted poison damage and length
Conclusion: Damage conversion is applied after off-weapon +% Damage and Deadly Strike are applied, but before resistances are applied. This is similar to how Fire Arrow converts weapon damage to fire.
By the way, has anyone tried this before? I searched the forums but no one seems to have ever tried converting weapon damage to poison damage via skills.txt.