1. #1

    Echo of Light - how does it work?

    I'm curious about Echo of Light. I always thought that casting any healing spell after another would get rid of the echo of light, potentially causing an issue. For example, if I cast Greater Heal and then a heal before echo of light is over, then the Heal HoT overwrites the GH HoT.

    I'm noticing, however, that everytime I cast a heal on myself, the Echo of Light HoT grows in strength, even if its the same heal. My only procs are SPI procs, and I don't think we have a spirit>SP/Int coefficient, right?

    I'm assuming then that Echo of Light hots roll into each other?

  2. #2
    The Echo of Light procs stack with each other
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  3. #3
    High Overlord Landfall's Avatar
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    Yeah they stack, if you stand there and spam heals on yourself they can get pretty high.

  4. #4
    Well a Disc Priest's Divine Aegis stacks... so why can't you Holy Priests have a stacking little heal tick. Also: http://elitistjerks.com/f77/t110245-...st_compendium/

  5. #5
    The way it works is as follows:

    When you cast a heal, the Echoes of Light buff will apply and heal them every second for six seconds.
    Let's say for simplicity that it is healing 100 health per tick for 6 ticks, for a total of 600.

    Now, when it has ticked 4 times (400 healing done), you land another heal on yourself. This takes the 200 healing left over from the previous Echo of Light (it had 2 ticks of 100 left), and adds it to the Echo of Light from your new heal, and applies that as a HoT.
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  6. #6
    Thanks Abandon that is exactly what I was looking for. So the last 2 ticks are then spread out over an additional 6 seconds or whatnot. Awesome.

  7. #7
    So... why is everyone saying that when using prayer of healing, you should do one group, then the other group, then WAIT for the echo tick, then heal again? If it's not overwriting, seems like it would just be faster to spam prayer of healing on the two groups and ignore the echo of light.

  8. #8
    Quote Originally Posted by tobberoth View Post
    So... why is everyone saying that when using prayer of healing, you should do one group, then the other group, then WAIT for the echo tick, then heal again? If it's not overwriting, seems like it would just be faster to spam prayer of healing on the two groups and ignore the echo of light.
    They are probably talking about the prayer of healing glyph, as that does get overwritten if you cast back to back.

  9. #9
    Quote Originally Posted by Chob View Post
    They are probably talking about the prayer of healing glyph, as that does get overwritten if you cast back to back.
    Ah, now that makes a lot more sense. Thanks.

  10. #10
    This is not entirely accurate; I did some testing to figure out what's going on with the Mastery thing, and I *think* it works like this:

    Echo of Light heals you for a certain percentage of the healing you cast, over 6 seconds. Every second, 1/6th of the extra healing is applied to the target, so it expires after the 6th tick. But as said, it can stack. However, it's not just being additive to add up to crazy numbers, but rather seems to add up the effects of the last 3 or 4 heals or so. You can see this by spamming yourself first with Heal, then switching to Greater Heal and back to Heal again after a while. Both will bring you to a certain equilibrium. For me, Heal puts me around 600 healed per second on Echo, while Greater Heal puts me around 1500. So yes, it will build up, but there's also some decay. In fact, looking purely at the decay, you're actually better off letting a high Echo run its length, than to replenish it with a low heal.

    I really wonder about the formula they implemented for it.

    Once you stop healing, the Echo will continue using the latest value it had. Note that this value is affected by crits, so Mastery is really benefitting a lot more from Crit than Haste.

  11. #11
    Echoes works just like the T10-2set, only it works for (almost) all heals.

    When casting any heal, your target get a 6 second buff holding 3 numbers. Each number contains the value your target will be healed for after 2, 4 and 6 seconds. So if you cast a Heal of 10k, and have 10% Echo, each of these numbers will be 333, 333 and 334.

    Should you cast any other heal, they will simply ADD to these three numbers. For example, if you now also cast a SoL-Flash Heal immediately after the Heal, healing for another 20k, you would now add the numbers 666, 667 and 667 to the numbers.

    Effectively the three numbers are now 999, 1000 and 1001.

    After each 2 seconds of the debuff, the first number is applied as a heal. In our example, it will heal for 999 healing.
    The next two numbers are then "shifted up", leaving the three numbers as 1000, 1001 and 0. The duration of the buff is now 4 seconds remaining, so only the first two numbers will apply anyway.

    Any more heal you land will again simply add to the buff. Assuming you now land a 25k Greater Heal. The first thing that happens is that the buff duration is again reset to 6 seconds. And the number 500 is added to each of the three numbers. They are now 1500, 1501 and 500.

    And maybe you cast a CoH for good measure. That's maybe another 200 to each number. They are now 1700, 1701 and 700.

    After another 2 seconds, Echoes again heals - for 1700 hp. Like the last time, it uses the first number as a heal, and shiftes the other two numbers up. New numbers are 1701, 700 and 0.

    If you now stand idling about, 2 seconds later, the next heal will heal for 1701 hp. And another 2 seconds later for 700, before letting the buff time out.

    Disclaimer: I haven't checked if this is how echoes actually work, but this was how the T10-2set worked. I believe they were using the same formula...

  12. #12
    My unbuffed Haste is at 12.77% (1215 rating on top of the base). The tooltip for Heal and Greater Heal shows a 2.22 second cast time in any case.

    My Mastery is shown as 14,06% (1086 rating on top of the base), giving +17% healing.

    I am currently looking at my combat log. I started casting a couple of Heals on myself (unbuffed completely) and I see the following:

    0:00 Heal 7738
    0:00 Gain Echo
    0:01 Echo 226
    0:02 Echo 226
    0:03 Echo 227
    0:03 Heal (Crit) 11675
    0:04 Echo 417
    0:05 Echo 418
    0:05 Heal 8099
    0:06 Echo 515
    0:07 Echo 515
    0:08 Heal 7685
    0:08 Echo 515
    0:09 Echo 483
    0:10 Echo 483
    0:10 Heal 8102
    0:11 Echo 559
    0:12 Echo 559
    0:13 Heal 7766
    0:13 Echo 600
    0:14 Echo 600
    0:15 Heal 7560
    0:15 Echo 600
    0:16 Echo 522
    0:17 Echo 522
    0:18 Echo 521
    0:19 Echo 521
    0:20 Echo 522
    0:21 Echo 522
    0:22 Echo 521
    0:22 Echo fades.

    I note a few oddities here. First of all, the Echo at second 8 and 15 still tick once for the old value, but shown in the log AFTER a new heal. The update to Echo only comes after that. Furthermore, the final streak consists of 7 ticks, not 6 (yes, I double checked this). Could it be that Echo ticks are affected by Haste as well?

    Next, I mixed in a few Greater Heals for good measure:

    0:00 Heal 7560
    0:00 Gain Echo
    0:01 Echo 222
    0:02 Echo 222
    0:02 Heal 7514
    0:03 Echo 331
    0:04 Echo 331
    0:05 Heal 7655
    0:05 Echo 444
    0:06 Echo 445
    0:07 Heal 8077
    0:07 Echo 445
    0:08 Echo 459
    0:09 Echo 459
    0:09 Heal 8123
    0:10 Echo 544
    0:11 Echo 544
    0:12 Heal 7824
    0:12 Echo 543
    0:13 Echo 501
    0:14 Echo 501
    0:15 GHeal 21480
    0:15 Echo 963
    0:16 Echo 963
    0:17 GHeal 21330
    0:17 Echo 1266
    0:18 Echo 1266
    0:19 Echo 1267
    0:19 GHeal 20970
    0:20 Echo 1248
    0:21 Echo 1247
    0:22 GHeal 20985
    0:22 Echo 1446
    0:23 Echo 1446
    0:24 Echo 1446
    0:24 GHeal 20095
    0:25 Echo 1311
    0:26 Echo 1311
    0:27 GHeal 21527
    0:27 Echo 1505
    0:28 Echo 1505
    0:29 Echo 1505
    0:29 Heal 7968
    0:30 Echo 986
    0:31 Echo 986
    0:32 Heal 7610
    0:32 Echo 986
    0:33 Echo 715
    0:34 Heal 7578
    0:34 Echo 716
    0:35 Echo 699
    0:36 Echo 699
    0:37 Heal 7511
    0:37 Echo 686
    0:38 Echo 686
    0:39 Heal (Crit) 12437
    0:39 Echo 822
    0:40 Echo 822
    0:41 Echo 822
    0:42 Echo 822
    0:43 Echo 821
    0:44 Echo 822
    0:45 Echo 821
    0:45 Echo fades.

    Like before, it ends with 7 ticks, not 6. Also, the pattern of the last 7 ticks appears odd; it starts with 4x 822, then an 821, another 822 and it ends with 821. If there is a rounding issue, you'd expect the values to be interspersed on regular intervals, but that's not the case here.

    I'll do some number crunching myself as well (as time allows), but this sample might help other crunchers as well.

    Edit: I just had a Echo series of just 5 ticks. It seems to be dependent on when you gain the Echo and when it is set to expire. If you're lucky, you get an extra tick; if you're unlucky, you get one less.
    Last edited by Kaysha; 2011-03-04 at 02:25 PM.

  13. #13
    Now try to sum up every direct heal and then sum up every echoes. The result should be echoes = x% of your direct heal where x% is your mastery.
    Abandon did explain it very well, it's a bank system.

  14. #14
    Quote Originally Posted by rafik View Post
    Now try to sum up every direct heal and then sum up every echoes. The result should be echoes = x% of your direct heal where x% is your mastery.
    Abandon did explain it very well, it's a bank system.
    I just did this but it isn't adding up to 17%.

    For the first example: Heal did 58,625. 58625*.17= 9966.25

    However, if you add up the Echoes they heal for 10594

    10594 / 58625 = 18%

    I didn't do the second example.

  15. #15
    If you work through the Mastery rating, and figure out the percentage, it's actually 17,57%. That makes the Echoes come out at 10300. Given that you sometimes get an extra tick out of it (and sometimes, you don't), it seems accurate.

    However, I still haven't been able to pour this into a formula myself - which is also because I am busy with something else at the moment .

    To sum up my two samples: sample one, healing done total = 58.625, Echo = 10.594. Sample two, healing done total = 216.244, Echo = 38.597. Both are very close to the 17.57% mark that I'm getting from Mastery.
    Last edited by Kaysha; 2011-03-04 at 03:32 PM.

  16. #16
    edit : I had to relog, my part about blizzard UI rounding mastery % from it's rating disapeared, but Kaysha told it ... ^^

    ...Anyway this is how mastery for holy works, but just like kaysha's edit, there may be some oddities with the refresh of EoL based on when the heal lands.
    If you gained one more random tick, that's great, as it's just that we're not suppose to lose any heals from echoes
    Last edited by rafik; 2011-03-04 at 03:30 PM. Reason: relogging bad copypast

  17. #17
    I think I've figured it out, by just dumping the values into an excel sheet and working some with the supposed banking formula that's behind it.

    In the case of Heal, it seems to be somewhat buggy on two fronts. I'll use my first example, in which I only used Heal.

    After gaining Echo, it ticked for 226, 226 and 227. Total budget would have been 1360 (17,57% of 7738). The next heal brought its own budget of 2051 (17,57% of the crit value of 11675), on top of which came the remaining budget. This should have been 679, which would bring the next Echo tick to 455. However, for some reason it assumed that the reservoir had not been drained 3 times, but actually 4 times. This left not 680 in the reservoir, but instead only 454. Adding that to the budget of the second heal brings the new tick value to the observed 417 (2051/6 + 454/6).

    This bug is something that appears in both samples listed above. As you can see, it reduces the effective value of the Echo ticks over time, albeit by a very small value, namely the first tick over the entire duration. Further investigations are needed to see if it's generic for all heal spells, or specific to Heal. And if it occurs at all times, or just every now and then (and that I was "lucky" to get it in both samples). I suspect this may be a lag issue as well, or that the initial Echo gain is considered the start of the chain as well, while the first real tick only occurs after 1 second!

    Of course, getting sometimes 5 or sometimes 7 ticks while it should be 6 could be considered a bug as well. Looking at my examples, and correcting for the missed initial tick in both and substracting the extra 7th tick, one gets a total Echo value of 10299, which is very close to the computed 10300. For sample two, it's 37998 with the correct sum, and 37994 calculated. I'd say that's within error margins due to rounding and truncation.

    Besides that, Heal also behaves odd in the way that Echo ticks are refreshed. As you can see in the logging of my samples, sometimes an "old" Echo tick follows a heal, only to get updated on the next tick. This is a cosmetic issue, probably due to lag. The old entry and the healing statement should be swapped in the logging and then everything works out as it should be. For some reason, this logline swapping does not occur for Greater Heal. I can't say if it happens for other healing spells as well. I am guessing this might be an issue for logparsers, though, which might calculate the derived values incorrectly as a result.
    Last edited by Kaysha; 2011-03-04 at 05:05 PM.

  18. #18
    The swapping not only on logs or EoL happens a lot, example for priest is mind blast cued with SWD, pratical is SWD lands before (any instant cued after a casted spell), more specifically where MB would put the target below 25% ... SWD does not consider it and "lands before" : x3 damage is ignored. You need to take a little delay to counter it.
    As long as EoL overall stays within margin (rounding etc), I think it's not really an issue, yet

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