A Serious Talk About Corrosive Projection

[Tragixx]

Original post can be found in the spoiler.

 

[starting note: I hope this belongs here...i didn't see a better fitting category.]

 

I can't help but think of how useful Corrosive Projection can be for high wave defense, or for T3 missions, especially in the current state where the difference between armor peircing/ignore or bullet damage is a 'make it/break it' for weapons. While the other two mods that came out at the same time are moderately useless in the current game, what about this guy?

The most commonly accepted setup is for everyone to have energy siphon. In speed runs, this may be the difference between using an ability or not. But once you get into the swing of a defense mission, unless you're spamming an ability, or enemies die from other means (Void lasers, chaos) the drop rate of energy orbs is pretty high. And now with the new set up, if you really need some extra starting energy, your squad can now, with a bit of communication,break all the containers before the first wave starts. For those following the old 'meta' of everyone having energy siphon, it even has the same polarity. So you can switch between without having to grab another forma.

Resistance in general, like I said, is a make it/break it for choosing your 'OP' weapon. While shotguns and melee weapons both get love from mods for 90% armor piercing, as well as a nightmare mod for 60%, rifles and pistols are stuck with an embarrassing 60% and 30% max, respectively.

The mod reduces enemy armor by 5/10/15/20/25/30%. Like all auras, it starts at a base increase of 4, going up to 7, or doubled to 14 with the correct polarity. The wiki doesn't provide enough information, though. It states that the mod was originally broken: "It's currently bugged (very likely) so that it counts twice for the players in the lobby before mission starts, then once for he players that join directly into the mission. It stacks multiplicatively."

I assume stacking multiplicatively is intended. However, I can't find any other source of information beyond that. I'll be testing out the mod here and posting results. I encourage others to do the same!

 

 

As it currently stands, Corrosive Projection starts additively, for a max for 120% enemy armor reduction. This means that player damage, including bullet weapons, elemental mods, and warframe ability damage....until 2000 armor. Then corrosive projection seems to not work at all, and full armor is being counted. 

 

2000 armor is about level 130 for ancients, 376 for Grineer heavies, 382 for fusion moas/corpus techs, and around 140 from grineer lancers/scorch/etc.

 

 

This is, for all intents and purposes, a bug. Something goes wrong. The most accepted speculation is that it has to do with corrosive projection stacking additively, and not multiplicatively.

 

The good news is, DE is talking about armor and it's effects. That much has been confirmed via community hot topics.

Edited August 9, 2013 by Tragixx

[DanPaul7]

I always use corrosive projection... very nice aura indeed.

[kamimegurine]

Yes if u are doing high lv def missions u will be sapming your powers a lot, mobs wont die from a single ult you know ??? energy siphon is way better, just go with Acrid and no armor will harm your dmg

[Eisvogel]

It's SUPER useful for high waves defense, three of them practically negate all armor effect

 

Thing is.... ES is still probably more useful due to broken frame skills. Mainly frost globe and vauban bastille. That will get you through any defense

Edited August 9, 2013 by Eisvogel

[Tragixx]

Yes if u are doing high lv def missions u will be sapming your powers a lot, mobs wont die from a single ult you know ??? energy siphon is way better, just go with Acrid and no armor will harm your dmg

 

If you are using elemental mods on Acrid, which you should be, you're still dealing reduced damage from those elements.

 

At least, you should be, looking at the formulas, unless you're hitting a special unarmored spot.

[Kobalt]

Yeah those notes on the wiki are old and refer to how the old artifact card used to work, it doesn't apply anymore. I was on one day trying to test for someone in one of my threads the effects of having four people running the aura. Sadly, I never could get together enough people who were interested and no one seemed to know. It may stack differently than other auras, remove armor all together or invert armor causing additional damage from non-armor ignoring sources. I would love to get some verification on what four of the auras together will do from someone who has tried it...Not someone who is guessing at how it should in theory work!

It would be as easy as taking a nice unmodded bullet damage weapon like a Lex and shooting a Grineer of any level in the chest in a group of four people with the Aura on!

Edited August 9, 2013 by Kobalt

[Tragixx]

It's SUPER useful for high waves defense, three of them practically negate all armor effect

 

While i'm not saying high wave defense is super difficult, I personally have a hard time slowing down enough to also look at the numbers i'm putting out. Feedback like this makes me want to run a group, 4 energy siphons and then 4 corrosives, and see how much of a difference it makes. Especially if it makes some weapons more viable (or even optimal?) that would normally be a waste.

[Tragixx]

 I would love to get some verification on what four of the auras together will do from someone who has tried it...

 

Color me interested ;)

[Kobalt]

I have a fully ranked Corrosive Projection and will be on throughout the night. I can bring a friend of mine in about a half hour, but we would need one more person.

[Eisvogel]

While i'm not saying high wave defense is super difficult, I personally have a hard time slowing down enough to also look at the numbers i'm putting out. Feedback like this makes me want to run a group, 4 energy siphons and then 4 corrosives, and see how much of a difference it makes. Especially if it makes some weapons more viable (or even optimal?) that would normally be a waste.

 

The main problem is what i pointed out after that..... since some frames can get you thru any wave (vauban/frost), ES becomes a guaranteed win due broken frame's skills.

 

And of course, the armor effect can be bypassed with AI/AP weapons, where the only damage suffering will be the elemental dmg mods.

Edited August 9, 2013 by Eisvogel

[SirSlayer]

The main problem is what i pointed out after that..... since some frames can get you thru any wave (vauban/frost), ES becomes a guaranteed win due broken frame's skills.

Might be true but why not but once in a while you wanna try stuff.

[Eisvogel]

Might be true but why not but once in a while you wanna try stuff.

 

Of course, the point was about why most people will still prefer ES over anything

[InsomniacOvrLrd]

any word on this? I'm very curious about how useful corrosive projection is in a party, but i don't personally have it. My one friend who plays this game a lot insists on foolish things like rifle amp, enemy radar and steel charge all the time, so it'd be difficult for me to test.

 

I feel like 2 energy siphon and 2 corrosive projection would be a good loadout, though.

[Tragixx]

I got called into work, so while I can browse the forums, I probably wont be on for a while... (read: ~12 hours).

 

still super excited to try this out, though. So those with corrosive projection...we should try it out tomorrow :)

[SirSlayer]

Only thing I'm interested in what happens when you over -100% armor.

Will it be "just 0" or it will it amplify damage? Or maybe just knowing WF it will crash/make the enemys invincible or something :S

[Eisvogel]

Only thing I'm interested in what happens when you over -100% armor.

Will it be "just 0" or it will it amplify damage? Or maybe just knowing WF it will crash/make the enemys invincible or something :S

 

Mostly it depends if they use negatives or not..... if they don't, it will be 0..... if they do, it will amplify damage with the current formulas.

[xveganrox]

I run Corrosive Projection most of the time and occasionally get reprimanded for not always having Energy Siphon on. The way I see it, though, is as you said - there are plenty of energy drops and with full Streamline and 400+ energy I hardly feel the need for 4 Energy Siphons.

[WhiteTrick]

yep its my #1 aura next to siphon, as long as we have a siphon in the party i bring crosive

[Kobalt]

We did tests up to three users tonight and got these results, using a Lex and level 1 Grineer Lancer torso shot as baseline...

No Aura - 23

1 Aura - 29

2 Auras - 38

3 Auras - 58

The results show that the buff is additive, sadly once again we could not get a fourth. Checked all channels including council, understandably void missions took gross priority over my curiosities.

For those of you who don't know how armor works...

Damage Scale = 100/( 100 + Armor Value * Armor Scale[your corrosive projection])

In the case of a level 1 Grineer Lancer the Armor is 200, so...

0.33~ = 100/300

23.33~ = 70[lex damage] * 0.33~

This gets us our 23 damage when you adjust for rounding! Now for with one aura!

140 = 200 * 0.7 [30% reduction]

0.4166~ = 100/240

29.166~ = 70 * 0.4166~

29 onto two auras!

80 = 200 * 0.4

0.55~ = 100/180

38.88~ = 70 * 0.55~

Rounding is a little funky on this one, at this point the results only make sense if DE is flooring their decimals when rounding. It would explain the results perfectly! Lastly, with three auras!

20 = 200 * 0.1

0.833~ = 100/120

58.33~ = 70 * 0.833~

Once again we get our results proving that the mods do stack additively!

~ - Represents repeating decimals. Sorry couldn't get proper overscore tag.

I won't begin to speculate too much on armor inversion and whether it is or isn't in the game. My personal guess is that it won't work and will simply cap out at 100% reduction. The reason being that it would amplify damage vs. armored enemy's greatly [more armor = more damage]. It would absolutely trivialize defense missions while introducing the potential for divide by 0. The only way I could see it working out is if the cap the % of excess damage that can be applied this way.

I guess we will find out tomorrow at some point if the stars align!

[leglesslizard]

I'm really interested in the viability of corrosive projection and I'd be very happy to help test it, if I had it. The fact that it appears to be additive is fairly surprising to me though, because that implies that it would be possible to get enemies with absolutely no armor mitigation making any weapon you used and all it's mods "armor ignore." It looks to me like this would be much preferable to energy siphon in higher level defense as the damage increases on just the elemental damage mods would be worthwhile, while energy problems might be remedied by a Trinity. Then again, I haven't tested anything. I'm very curious to hear how this test goes, and am eagerly awaiting further results.

[Tragixx]

To use the term "flooring decimals" is exactly what happens.

In programming, it's called truncating. What happens is, the calculated result is casted to an 'integer' data type in the computer's memory. This datatype doesn't hold any decimal values. And, unless specifically told to, and it seems like it isn't, it isn't rounded up, either. So whether the number is 10.00001 or 10.9999999, after calculations, it is simply 10.

I had a chance to log in during my break, and did a very quick test with a friend, who had a -15% aura. I'm crossposting the results we had from Tumblr, so hopefully everything looks okay after formatting. Basically, i'm finding that they stack additively as well.

Opening: all formulas,etc. are gathered from datamined stats, found here: https://docs.google.com/spreadsheet/lv?key=0Au6mBXle3cFtdHBYUzVJaDJfdkIzSEN1cUh5UlRvckE&f=true&noheader=true&gid=9

Credit for that goes to /u/Pwnatron on Reddit, not me.

So I had the chance to test out this mod not too long ago.

Weapon I used was Latron Prime. Base damage is 45. With no mod, it was doing 7 damage. with a full mod, 9 damage, and with a full plus a 15% corrosive, 11 damage..against a level 58 Grineer Elite Lancer (Exta, Ceres).

Lancer base level is 20, with base armor 200. So at level 58..

This guy is sitting comfortably at 525.6 armor. Since formulas truncate decimals, it gets chopped down to 525.

Armor = (current_level - base_level)^1.40 * 0.01 * base_armor + base_armor

Damage calculation on an armored location is: 100 / (armor + 100) * damage * damage_type_mp * special_spot_mp

I purposely made sure I was aiming at their gut, and using latron prime, the damage type was bullet. Making damage_type_mp and special_spot_mp both 1.

This comes out to 7.2 damage at full armor.

With a maxed corrosive projection, enemies suffer -30% armor. so, our friend is down to 368 armor.

Plug that into the formula and you get aprox. 9.635 damage. Again, truncate, the game calculates 9 dmg.

Here's where the numbers get strange. To figure out how much armor this guy was at with my maxed aura and a -15% aura from a friend, I plugged in the rest of the numbers. again, in game, we did 11 damage.

Solve for x, and you get 309 armor.

11 = 100/(x+100) * 45 * 1 *1

But how? If the mods stacked additively, that would be -45% armor, putting the target at 289 armor.

If they stacked multiplicatively, that would be -34.5% armor, that would leave the target at 344.

Then, I plugged those numbers in.

If the target had 289 armor, that would be 11.56 damage.

at 344, 10.1 armor.

This leads me to think that the auras stack additively? Would that really mean -120% armor, or with 3 maxed, -90% armor and then room for energy siphon, or a rifle amp?

Edit: with more thought, assuming the formula I have is correct. the game wouldn't divide by 0, because you add 100 to that 0 before multiplying/dividing.

Edit 3: I can't tell if my math is horribly wrong because I did it at 2am, or if I'm not reading what I wrote correctly because its now 3am....

Edited August 9, 2013 by Tragixx

[Eisvogel]

It would be nice if we could get a dev's confirmation for this just in case

[Tragixx]

It would be nice if we could get a dev's confirmation for this just in case

if results with 4 maxed auras are grossly overpowered, ill be sending PMs to Steve/Scott..

Edited August 9, 2013 by Tragixx

[SirSlayer]

if results with 4 maxed auras are grossly overpowered, ill be sending PMs to Steve/Scott..

Armor is working as intended.

[Eisvogel]

Armor is working as intended.

 

Why would you quote that faq, when it's already in hot topics and it's regarding ARMOR SCALING, not the topic at hand => corrosion aura