I totally agree with you, lequintal69, when you say there were little confusions in the answers that were given to you previously. In addition to some factual mistakes (12-second cap), Diminushing Returns were discussed instead of heartbeat.
Regarding binary spells hit chance :I'm really too tired to look for something regarding Binary Spells hit chance calculation right now. It shouldn't take long if you lookup yourself though
. But that doesn't really matter anyway, it's not the point of this thread.
Regarding fear break chance :Fear effects don't have the same heartbeat mechanic. It's not a sheep, it's not a sap, it's a on-damage break chance spell, like Frost Nova
.
As far as I know, the formula was modified several times by Blizzard during vanilla, but in 1.12, long story short, dots have a very little chance to break Fear each time they tick, while direct damage spells have a higher one that becomes a 100% chance after a certain amount ; against mobs it's way harder to get your Fear to break than against players.
So basically, breaking a fear with dots only on a mobs target means huge amount of damage caused by dots in a very short timespan, it's basically impossible in solo.
Regarding the chance to break over time because of spell hit chance (heartbeat) in addition to this, I couldn't tell you right now honestly, I guess there is one too. I'm not 100% sure, but thorough searches have been carried out by the staff a long time ago, I can assure you that
. Anyway heartbeat still matters less for fear effects than it does for Poly for instance. The base duration is 20s vs. 45s and it might come into play in the heartbeat formula.
Anyway, back to the topic,
i.e. spells with a "normal" heartbeat like Polymorph or Sap : of course mobs have a heartbeat chance to have the cc effect to fade before its full duration.
The formula is just not the same for mobs / players. I don't know how the staff scripted the formula here, so I couldn't tell you any more information. Maybe the checks are far more frequent on players than they are on mobs, or the miss chance applied in the formula is multiplied by a certain amount or something for players, I have no idea.
But basically, a polymorph on a mob of your own level with no special resistance or anything usually last its full duration, especially if you have a little +hit on your gear / template, reducing your miss chance to 1%. The same situation with a player instead of a mob can lead a polymorph to last very long (NOT 12s maximum), but in average its definitely something like 10-15s rather than 30+.
Hope this helps out
.