Unfortunately, perc_add operation cannot be used within <triggered_effect>.
But I found another solution which seems to work.
In my medic perk I set the healing factor like this:
<effect_group> <triggered_effect trigger="onSelfPrimaryActionEnd" action="ModifyCVar" cvar="HealingFactor" operation="set" value="@PerkHealingFactor"/> <triggered_effect trigger="onSelfSecondaryActionEnd" target="other" action="ModifyCVar" cvar="HealingFactor" operation="set" value="@PerkHealingFactor"/> </effect_group>
And then I extend the buff which handles all healing stuff and apply my healing factor.
<append xpath="/buffs/buff[@name='buffHealHealth']"> <effect_group name="Apply Healing Factor from Perk"> <triggered_effect trigger="onSelfBuffStart" action="ModifyCVar" cvar="medicalRegHealthAmount" operation="multiply" value="@HealingFactor"/> <triggered_effect trigger="onSelfBuffStart" action="ModifyCVar" cvar=".healHealthAmountDisplay" operation="set" value="@medicalRegHealthAmount"/> <triggered_effect trigger="onSelfBuffRemove" action="ModifyCVar" cvar="HealingFactor" operation="set" value="1"/><!--not sure if this is needed--> </effect_group> </append>
At this point the medicalRegHealthAmount from the item was already set.
In Singleplayer it seems to work. But I need to check if this also works in multiplayer when healing others.