M&M Impervious Protection vs Impervious toughness

[Tanarii]

So Protection with the impervious modifier adds protection ranks to your toughness and you ignore damage if it's 1/2 of the protection ranks.

Does the impervious toughness modifier add protection ranks to your toughness and you ignore damage if it's 1/2 half of your toughness without the protection ranks, or toughness with the protection ranks?

[Rynjin]

I'm not 100% sure I understand the question so I'll just break down how the two powers and the modifier work as I understand them.

Toughness is one of your base attributes, it determines how much punishment you can shrug off.

Impervious is a modifier to Toughness that makes you immune to Damage effects equal to or less than half your Toughness, rounded up.

Protection is a power that grants you +1 Toughness per rank, otherwise it functions exactly as normal Toughness save for the fact that it can be Nullified.

Protection as a power simply adds to your Toughness. It doesn't separately interact with Impervious, save that if your powers are Nullified for example, it will reduce your Impervious threshold due to your Toughness being lowered.

[Tanarii]

Impervious is a modifier to Toughness that makes you immune to Damage effects equal to or less than half your Toughness, rounded up.

Ah okay. I'm using the 3e Basic Heroes Handbook, and it has "Impervious Toughness" as a modifier under Protection. So I thought it was a modifier to the Protection power. And was trying to understand the difference between:
Protection (impervious)
Protection (impervious toughness)

But looking at the premade Archetypes and sets of powers they have, they have something like either of:
Protection 7 (impervious)
Toughness 12 (Impervious)

And in all cases, the archetype is set up so that particular group of choices always leads to a specific Toughness value for the character, and the power has been 'purchased' at that specific rank.

So to be clear, Toughness (impervious) is a direct modifier to Toughness, it has nothing to do with the Protection Power adding to Toughness?

That also explains why there's also a note that other defenses can be made Impervious.

[Rynjin]

Correct. Technically you could apply your Impervious to Protection as well, I think, but the only thing that would do is make it vulnerable to power nullification.

I don't actually own the 3e books (only the 2e ones) and work entirely off of the SRD (https://www.d20herosrd.com/), so I'm not sure how it's laid out in the books.

[Tanarii]

I think the value of adding it to protection is you only have to pay for adding to the protection ranks, as opposed to your entire toughness (Probably enhanced by paying for that).

[Rynjin]

It's just a flat +1 per rank of Impervious in either case, so the cost is the same. It's not a modifier like Area which doubles the cost of a power (well, technically adds +1 cost per rank), for instance.

[Tanarii]

Sure.

But it looks like you have to pay for impervious for all of your toughness including that from stamina. And you'd have to buy enhanced stamina up to the same value as protection added.

If you buy protection that's 1 per additional added to toughness only, then you only pay for impervious for only your protection ranks.

So you end up paying extra for the base toughness (from enhanced stamina), but have a higher impervious value. More cost but bigger benefit.

[Rynjin]

I misspoke, sorry. 2e's Impervious is just a flat cost (1 point per rank of ability you can ignore, so Impervious Toughness 5 means you ignore Damage rank 5 and lower).

3e impervious IS actually a +1 cost per rank ability, so you're right. Though having it split like that typically isn't a great idea. Impervious is already really only good against fodder (who you'll have no trouble with anyway), so neutering it even more isn't the greatest idea.