Title says it all really. If I convert a skill to say fire AND lightning (e.g. disintegrate), how does the game know which damage type to apply to the skill, or do BOTH tags appear on the skill now ?
If Iām understanding your question correctly:
Disintegrate as a base skill has both the lightning and the fire damage tags.
When specializing in Disintegrate and building your character youāll decide whether or not you want to scale fire or lightning damage. Once decided, thatās the gear you would be targeting and the direction on the skill tree youād want to spec towards to scale that damage type further.
If you choose to scale lightning, youāll path to the Electrify node and beyond on the tree which converts all fire damage to lightning damage or the Infernal Ray node which converts all lightning damage to fire damage and has surrounding nodes that scale fire damage further etc.
Electrify and Infernal Ray are mutually exclusive, one deactivates the ability to use the other. I donāt know if not speccing either one of these and scaling āElemental Damageā is optimal as Iāve never built a Disintegrate build myself.
TLDR: The skill starts with 50/50 conversion between fire/lightning. Your build and how you want to scale the damage of Disintegrate is up to you and which node on the tree (Electrify vs Infernal Ray) will determine how it scales.
Or both, given theyāre both elemental.
Generally on conversion nodes one of them will say that it has no effect if the other one is taken as well.
Nothing in Disintegrate is optimal.
If a skill (such as disintegrate) has multiple elemental tags (either by default or from conversion) then the base damage & any adaptive damage is split equally over all tags.
So I half answered my question myself.
If you take a skill (say disintegrate or explosive trap), and select more than 1 damage conversion node, then you get each damage type tag added to the skill, so explosive trap can have cold, lightning and fire for example if I choose the coldsnap node and the static node. But does this also mean the damage ātypeā actually applied is now 33%/33%/33% in the example of explosive trap ?
EDIT:- just read @Llama8 comment about the damage being split between the tags, so that answers it.
I suspect that that is due to explosive trapās Trapas node. If you unspec that node then itād probably just have the lightning tag given the cold node explicitly states that it is overridden by the lightning node.