Ultima Online Five on Friday Q&A

EA's Jeremy Dalberg has posted another one of his "Five on Friday" Q&A features on the official Ultima Online website.
"The Life Leech and Mana Leech properties seem to be outside of the proper intensity range when I use a runic weapon. What's the deal?"

The chance to hit on Mana and Life Leech (but NOT Stamina Leech) are scaled based on the swing speed of the weapon. First, the SSI, if any, is run through an equation to create a modifier. Then that modifier is divided by 4 and multiplied by the intensity to get the actual proc chance (capped at 100%, of course.) Then, if it's a ranged weapon, the chance is cut in half. Faster weapons will have a smaller chance, and slower weapons will have a larger one, at the exact same intensity value. (The tooltip, as near as we can tell, is correct as to the actual chance for the effect to go off. It's just not at all representative of the intensity.)

What this means is, short of running some wacky math on every weapon you create, a crafter can't really tell what intensity he's rolled on a given weapon. I've updated the Item Properties page with a note to that effect :P

(Again, none of this applies to Stamina Leech - its intensity is simply its chance to hit / 2.)