With over 30 perk points to spend on my current character, I decided to take a bunch I find useful, but unnecessary.

One of these is Rad Resistance. I take all the levels, finally netting me +30 in resistance.

That is, until the Glowing Sea belches out another rain storm. I'm still taking 1 or 5 rads per lightning strike.

Wouldn't a +30 negate this to <1?

Rad-X is +100 and works to <1.

I also tend to notice nothing is reduced walking by yellow barrels, still giving me max dosage.

Is this perk glitched or am I not understanding what it's supposed to resist?

From what I can tell rad resistance is a proportion and not an absolute reduction.

100% reduction equates to half of the rads taken.

So for example, if you were to going to take 20 rads per sec, a +100 rad reduction would mean you would actually take 10 per sec. Because 20 is 100% of 10.

I'm not a math wiz but I'm pretty sure 100% of 20 is 20 lol

Resistance in Fallout 4 works on a series of ratios. Getting higher resistance will greatly lower the damage done by STRONG weapons/source of rads, but do little to negate that of weak sources of rads like from rad storms.

• 50 damage against 0 damage resistance (no ratio): ~50 damage is done (~0% damage reduction).


• 50 damage against 10 damage resistance (1/5 ratio): ~45 damage is done (~10% damage reduction).


• 50 damage against 25 damage resistance (1/2 ratio): ~32 damage is done (~35% damage reduction).


• 50 damage against 50 damage resistance (1/1 ratio): 25 damage is done (50% damage reduction).


• 50 damage against 100 damage resistance (2/1 ratio): ~19 damage is done (~61% damage reduction).


• 50 damage against 250 damage resistance (5/1 ratio): ~14 damage is done (~72% damage reduction).


• 50 damage against 1000 damage resistance (20/1 ratio): ~8 damage is done (~83% damage reduction).

Maybe I should have said 20 is a 100% increase over 10.

Don't waste perks on rad resistance. Just carry a Hazmat suit.

This. The minimum environmental radiation in the Glowing Sea is 10 rads - one rank of Rad Resistant will halve that, further ranks will reduce it less but be much more helpful against higher radiation sources like the pools of water. I've realized Rad Resistant isn't a bad perk for the buff it offers, it's just that it's too easy to get a similar amount of rad resistance really easily. Modded vault suit nets you what, 20?

I'm trying to reverse engineer the math your doing here but I'm not seeing it. What's the mathematical equation (x = base damage, r = resistance, y = actual damage)

Edit: Never mind, I found the wiki: http://fallout.wikia.com/wiki/Damage_Resistance

It's explained in this http://fallout.wikia.com/wiki/Damage_Resistance#Fallout_4.

"the amount of damage reduction the player character gets out of the damage resistance is actually based on how much potential weapon damage is coming in; unlike previous games, net damage reduction is based on a ratio between the potential weapon damage done and the damage resistance, with diminishing returns for high damage resistance.

The amount of damage reduced by damage resistance climbs very quickly until damage resistance is about half of the potential weapon damage, after which diminishing returns means you get less and less damage reduction per point of damage resistance. Notably, if damage resistance is exactly equal to the potential weapon damage done, then exactly half of the damage is negated. In other words, if you have 50 ballistic damage resistance and are shot by an enemy doing 50 ballistic damage, then you'll receive 25 damage."

I popped back into the game after reading this because my initial thought was I wasted 4 perks*, but FTd over to the light house to take on those Children of Atom. Sure enough, the rad hit was severely negated. I used to get 99 rads/sec, now it's 47.

That makes it worth it. I may not be able to protect against a storm, but those gamma guns bite (more enemies are now using them).

Thanks for the info.

*Not really. I really didn't know what to spend my perks on since I had all the ones I wanted, so I'm just toying around with different perks to see what they offer.