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### Magic Penetration and Negative Values

Trashcat1

Junior Member

I have a few questions about magic pen and how it works.

1. Does magic penetration approach negative values of magic resistance when it is higher than magic resistance, i.e. 40 magic pen with 30 magic resistance on target would result in -10 magic resistance therefore amplifying your damage?

2.If question 1 is answered by yes, is negative magic resistance calculated in the same fashion as positive magic penetration, i.e. 31 magic resist =23% reduction, so would -31 magic resist from penetration then amplify your damage by 23%?

3.Lastly if anybody knows the formula to calculate this please post it, thank you.

Swarna

Senior Member

Armor can reach negative values but it is treated as 0 in damage calculations. I assume it is the same case with magic penetration.

Fluffy1

Senior Member

there are 2 things, MR penetration and MR reduction. reduction can take take MR into negative but penetration cannot go below 0. also note that any reductions are applied before penetration's starting with Flat pen or reductions then % based, this makes it very difficult to get someone into negative, but its fairly easy to drop someone to 0.

example:

you have sorc boots (20 penetration) abysmal scepter(-20 redution) and a void staff (40% penetration) and your oppoent has say 50 MR.

first the scepter kicks in dealing -20 leaving them with 30. then the sorc boots kick droping them 10, a void staff then works and takes off 40% in what case is a measly 4 leaving them at 6 MR.

if you also had a haunting guise then you would have drope them to 0 and viod staff wouldn't have done anything at all. im pretty sure all this can be found in the mechanics thread in guides and strategy section.

hope that helped

Ponies Gonna Pwn

Recruiter

Quote:
UntimedFury:
Armor can reach negative values but it is treated as 0 in damage calculations. I assume it is the same case with magic penetration.

Don't screw with new players like that.

Penetration occurs after armor/mr reductions like Black Cleaver/Scepter, and cannot pierce below 0. Reductions on the other hand, will cause negative values that result in damage bonuses against that target.

Trashcat1

Junior Member

Thanks for all the helpful information, i kinda wish penetration would go into negative values though lol, gangplank lolwut

Krosan

Senior Member

I do not know what order effects are applied in; someone else may be able to tell you what order Magic Resistance Reduction (effects like Fiddle's aura, Starcall stacks, etc), Magic Penetration (some items/runes), and void staff percent penetration take place in, but it ain't me.

I will tell you that, if you have enough reduction to push someone negative, they get extra damage. This doesn't come up much in regular play, since actual magic resistance reduction is not that common; I usually don't see it except in certain cases. Easiest way to see your damage go over normal is to bomb the same set of creeps a few times with Soraka's Starcall; you'll see your damage go over what your base+AP should be giving you, which is a sign that it's working.

After that, you could do some experiments. I could probably figure out for myself the application order and a bit about how they interact by going into bot games and playing with it, I just don't feel like it.

Serpentongue

Senior Member

Quote:
Fluffy1:
there are 2 things, MR penetration and MR reduction. reduction can take take MR into negative but penetration cannot go below 0. also note that any reductions are applied before penetration's starting with Flat pen or reductions then % based, this makes it very difficult to get someone into negative, but its fairly easy to drop someone to 0.

example:

you have sorc boots (20 penetration) abysmal scepter(-20 redution) and a void staff (40% penetration) and your oppoent has say 50 MR.

first the scepter kicks in dealing -20 leaving them with 30. then the sorc boots kick droping them 10, a void staff then works and takes off 40% in what case is a measly 4 leaving them at 6 MR.

if you also had a haunting guise then you would have drope them to 0 and viod staff wouldn't have done anything at all. im pretty sure all this can be found in the mechanics thread in guides and strategy section.

hope that helped

If I'm not wrong, percentage-based Magic Penetration takes effect before flat Magic Penetration, meaning the Void Staff's Magic Penetration effect will take place BEFORE the Magic Penetration from the Sorcerer's Boots.

Fluffy1

Senior Member

Quote:
Serpentongue:
If I'm not wrong, percentage-based Magic Penetration takes effect before flat Magic Penetration, meaning the Void Staff's Magic Penetration effect will take place BEFORE the Magic Penetration from the Sorcerer's Boots.

ah thought i was a little off, just went and looked at the sticky at the top of page again(been a while), heres what it says on the topic.

"Q: What order is armor penetration/MR penetration applied in?

A: From top to bottom

Armor/MR Reduction
% Based Armor/MR Penetration
Flat/Linear Armor/MR Penetration

Q: Can you reduce armor or magic resistance below 0?

A: Yes, although the only things that can reduce below 0 is Armor/MR Reduction. Both percentage and flat penetration do not have an effect after they get to 0 armor/MR."

think that answers all the questions fairly easy