Damage Threshold (DT) is an alternative way for armour to reduce incoming damage. Vanilla uses Damage Resistance (DR) which reduces damage by a percentage, while DT reduces damage by a flat amount, which makes it easier to calculate how much damage you'll take from any given weapon.
The current math is this:
FewerFlaws also made a really nice spreadsheet of common damage types you can encounter in Minecraft with a Damage Threshold vs Vanilla comparison:
If anything needs adjustments, let me know. I highly recommend pairing this mod with NoDamI and CombatEdit.
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