I pretty much always get it on PA cause it makes you even more tanky + aspd is great (aura too). Its actually really good item vs rightclickers or if you have people that really benefit from aspd it gives.
Most people are too dumb to understand the value of armor so I understand your concerns
took me a long time to adjust to abandoning str carries. Usually ac does best for me when I am second hardest carry on team not the number one.
what AC gives you is actually favorably comparable to a butterfly, for a slightly lower price. 55 vs 60 attack speed, the armor from AC actually gives more physical EHP then the evasion from butterfly(although evasion has other upsides). the extra right click damage from the armor reduction aura outclasses the 60 extra damage an agi hero would get from butterfly once your right click damage per hit is over 200(ish, estimate to lazy to get calculator). Its also grants the aura to your team and the debuff to enemies your team might be attacking.
the down side is that armor buffs/debuffs stop mattering if people build more then 30 armor, and you don't get the butterfly active.
@12, calculating the effective HP isn't quite that simple. Armor increases your effective hp by a static amount compared to your base hp. If you have 1000 hp and you go from 0-10 armor you now have 1600 EHP. Go up to 20 armor and you now have 2200 EHP. Same increase from base (600 more per 10 armor). But agility multiples your current EHP from armor even further. At 0 armor 35% evasion gives you a 35% increase in EHP, but if you're already at like 25 armor it takes you from about 250% EHP to 380% EHP. See this graph. That's why on high armor heroes like agi carries the EHP from butterfly is a lot more, but on low armor heroes like strength heroes the EHP from AC is a lot more.
http://dota2.gamepedia.com/File:Evasion.png
I think it's a pretty safe rule to say butterfly for agi hero, ac for everyone else. Unless you want to buff rest of your team.
EDIT: I was interested in some harder numbers so I plugged troll into devildesk. Take a look, huge difference in EHP and butterfly way ahead a typical level 16 troll build.
ac 5814 ehp
http://devilesk.com/dota2/apps/hero-calculator?id=DWTHYFi5mr1Be6DC
butter 7161 ehp
http://devilesk.com/dota2/apps/hero-calculator?id=i2Ex9AtMEYmTS6pX
It's actually saying even on most strength heroes that the evasion on butter gives more ehp than the armor on ac, but of course since the agi doesn't grant str dmg I'd still rather go ac for the debuff. Although of course you have to consider enemy builds mkb and then that evasion doesn't mean jack shit lol. And other ways to disable it too with hex.
"Armor increases your effective hp by a static amount compared to your base hp." "At 0 armor 35% evasion gives you a 35% increase in EHP, but if you're already at like 25 armor it takes you from about 250% EHP to 380% EHP"
neither of these are actually true, armor gives a 6% increase in physical EHP per point, meaning that its more effective the higher your Physical EHP is, up until 30 armor where additional points don't do anything at all unless you are effected by armor reduction.
any evasion item will also increase your physical EHP by the same percentage regardless of how high your EHP already is. 35% evasion doesn't give 35% more EHP it gives you 54%(give or take 1%) more physical EHP, it will give you this 54% increase regardless of how high your physical EHP already is, this is regardless of armor or even other evasion items .
the reason that the calculator was showing a much higher EHP for butter then for AC is that you passed the 30 armor soft cap on the troll build with AC. they actualy give just about the same amount of EHP if you don't pass the 30 armor mark. I overlooked that butter also gives you armor from the agility in my earlier post, butterfly does actually give you a bit more EHP then AC but no were near as much as your post states (unless you cranked your armor up past the soft cap which there is very rarely a good reason to do ).
I think you're wrong dude, as I understand the dota wiki, each point of armor is 6% more ehp from your base ehp. The equation is:
Effective HP = Total HP × (1 + Armor points × 0.06)
It's not: new EHP = old EHP x (1+ armor x 0.06) which is what you're implying.
Armor increases your EHP compared to your base health, not your current EHP. 1 point of armor at any amount is the exact same, it doesn't get more effective with more armor. If you have 1000 hp going from 10 armor to 11 armor nets you 60 more EHP. Going from 25 armor to 26 armor nets you exactly the same increase 60 more EHP.
But evasion does get better with higher armor, because it takes your EHP and multiplies it again. Evasion is worth even more to a high armored target than a low one (agi heroes vs str heroes).
I don't know of the soft cap. Where are you getting that from? And a soft cap is even more reason for an agi hero not to go AC, cus it's so easy to hit that on your own. Aquila and dominator is nearly 10 armor, added to innate agility and you're almost there.
So, what's better if yo want to tank Dmg?
1500 hp with 25% evasion, 25 armor or
2800hp with just 13 armor?
^depends on the type of damage you are supposed to "feel", and on whether you got lifesteal or not
@ timber we can sit here saying "nope I think ur wrong" over and over again about how armor/evasion work but there is not much point. maybe we can get input from someone here who tested it in game?
If you want to test the soft cap just go into a private lobby and buy 6 plate mails hover over the armor marker and see what % reduction you are getting from armor, then drop 3 of them and hover over it again, it will be the same number.
Just read the wiki. Read the equation. 1 point of armor gives exactly the same benefit whether you already have 1, 2, 10 or 20. Doesn't matter.
I can't find anything online about an armor soft cap or any cap. My guess is it's an interface bug not showing you the correct amount. But even then people have tested it, look:
http://www.reddit.com/r/DotA2/comments/1lyr3v/i_was_messing_around_trying_to_find_max_armor/
This sven went from 210 armor and 92% dmg reduction to over 1000% and it then said 98% reduction.
Minus armour is always good this meta, and with all the heavy physical damage heroes you need at least vlads on your team usually. AC+vlads makes your team so much harder to kill for that sniper, sf, jugg or troll on the other team. It's also one of the best items for 5man pushing, since your whole team gets +20 attack speed and the armour reduction works on towers (although deso is cheaper, but doesn't grant the extra +100 attack speed to your team).
Pricewise it might look expensive, since it basically turns the ingredients into auras (no extra attack speed or armour is added after buying the recipe). But they're still really good auras if both teams are physical heavy.
@The number 13
the function of agility to armor is linear, so if the function of armor to dmg reduction was linear, you could easily get 100% dmg reduction, and thats not true. the function of armor to dmg reduction is constantly growing, but second derivative is negative <=> additional dmg reduction from 1 point of armor is less as armor grows.
also it was way more obvious in dota1, where it was displayed clearly (+weird maps like Angel Arena etc., where u could easily gets thousands and thousands of armor), and i guess i even knew the exact function at certain point
OK so I was looking at it in game and both me and Timberwolf were wrong, as your armor goes up the increase in EHP per point of armor also goes up, but with each additional point of armor the rate at which EHP increases goes down.
number 12 it's simple math. Pay attention or I'm going to start calling you names because this is not fucking rocket science.
THIS IS THE EHP EQUATION:
Effective HP = Total HP × (1 + Armor points × 0.06)
LET'S APPLY IT:
1000 HP and 1 Armor
1000 x (1 + (1x.06)) = 1060 EHP
1000 HP and 2 Armor
1000 x (1 + (2x.06)) = 1120 EHP
1000 HP and 3 Armor
1000 x (1+ (3x.06)) = 1180 EHP
Are you noticing a trend?!?!?! EVERY point of armor is a 6% increase in EHP from your BASE HP. The rate of increase is CONSTANT.
What you are probably getting confused is the damage reduction because that is not constant. If it was your EHP would skyrocket and you'd become invincible. The dmg reduction tapers off but the net increase in EHP as compared to your HP is constant.
http://dota2.gamepedia.com/File:Armor.png
I'm pretty sure it's some sort of calculus actually but I haven't done that shit since college so I can't recognize the relationship at a glance.
I am sorry but you are wrong, I actually considered that you might be right, I went and tested it in game. It doesn't work that way. if you don't believe me go spend some time messing with it in a private lobby. there is a lot of misinformation on the internet. you can post the same link again and keep writing the equation if you want, but it just doesn't work like that.
Timberwolf is right.
Anyone wants to know how EHP and impact it has in terms of damage and therefor translation back to normal HP is ?
Number 12 you are obviously looking at something else. What did you test in game? WTF did you do? I'm dying to know cus there is no tooltip stating your EHP in game. You're just being stubborn and stupid at this point.
@iWin4Arka dmg reduction x EHP gives the amount of dmg absorbed by the armor. To get back to regular hp you just do EHP - (reduction % * EHP). 1000 hp and 10 armor:
total hp x (1 + armor x 0.06) = EHP
1000 x (1 + (10 x 0.06)) = 1600
The dmg reduction armor gives is:
(0.06 x armor) / (1 + (0.06 x armor)) = % reduction
0.6/1.6 = 0.375
0.375 x 1600 = 600 this much dmg is absorbed by your armor
1600 - 600 = 1000 this is how much hp you have
You can also get EHP based off the reduction equation by subtracting it from 1 to see how much dmg you take and then dividing your total hp by that.
1 - 0.375 = 0.625
1000 / 0.625 = 1600
კომენტარის დასაწერად გაიარეთ ავტორიზაცია.
Anyone else thinks item kinda needs a buff? it costs too much imo for what it gives, or mb its cause the heroes that need it the most - strenght carries, are just too shit this patch? IDK, always when i buy this item i don´t feel much stronger...