So I understand that all races have Rending as a special rule, but consider this:

SM's have 3 weapons in their codex that have rending, none of which will be in the game upon release.

CSM's have 2 weapons, both of which will not be in the game.

Orks have (idk?) weapons, but really, they aren't known for accuracy so I'm going to go out on a limb here and say not very many.

Tyranids. An absolute F*ckton in melee, but nobody will be playing as them (ok.. maybe a select few at a time), and nobody wants to get randomly one shot by a genestealer/ravenor anyway.

The Eldar have 14+ weapons that either directly have rending, or are based on a mechanic extremely similar to rending (Bladestorm & Monofilament,+ Distort if we're mean). On release, the Eldar will have at least 7 of these types of weapons, possibly an 8th, which means that critical hits are an integral part of the Eldar experience. Again, I doubt people will like seeing randomness as part of a loadout unless they're an Ork. If you're like me and played Vanilla WoW, you'll know just how infuriating random chance can be in a competitive setting. 50% to dodge as a rogue, and still dies to basic attacks, wtf?! Which means that critical hits should not be random, but instead skill based, like headshots.

Threading = Ranged Critical Hit

I propose that Bladestorm and other similar crit based mechanics be based on a "threading" mechanic. If your hit registers in very small grouping in a very brief period of time, the damage gets a small amplifier since you "threaded the needle" so to speak. So, for example, lets say a SM has 200 hp, 120 armor, 80 redbar. A shuriken catapult shaves 100 rounds a second from a 1000 projectile block. Each round deals 1 damage to hp and armor, and 2 damage to an unarmored head. If an Eldar absolutely buckshots the SM and doesn't get a single "thread" in the 2 second TTK, he'll be incredibly slow by this game standards and likely lose the firefight to a much more lethal (~ <1.35 sec Bolter to SM TTK) Bolter.

However, in that precious time, if the Eldar doubles up his shots, he'll sneak in an additional damage directly to the hp of the target equal to the shots doubled up on the same window. So 2 shots will be 2 damage to armor and 2 damage directly to the hp, 3 shots will be 3armor/3hp. The rate of fire will help even novice players get in a chunk of damage through armor into the hp of the target. A broken armored target is extremely vulnerable to an Eldar as the damage now just stacks onto itself: 2 threaded shots = 4 dmg, 3 = 6 dmg ...

Headshots on an unarmored target simply add an additional point of damage. (maybe there could be a weapon mod that adds an additional point of "threaded" damage to headshots, effectively doubling damage.

With an unmodified, body shots only Shuriken, a perfectly threaded shot will be 13 rounds, or a TTK of .13 secs - which is absolutely nuts I know, but this would almost be impossible to achieve unless the Eldar was very close to a stationary enemy due to Shuriken catapults not being accurate at medium distances. There's plenty of other ways to prevent near one shotting, like a damage cap, like most critical hit systems in game have - you know, like after a Ret Pally one shotted end game bosses in WoW. It's also unlikely that my example of damage would be implemented 1:1. The high rate of fire could be a hindrance to a highly mobile enemy, and missing means an auto-reset of the thread window. More than likely, Eldar will be getting vast rows of damage that look like this:


Assuming all 100 rounds hit:

1 hit, 1 dmg armor
1 hit, 1 dmg armor
2 threaded - 2dmg armor + 2 dmg hp
3 threaded - 3dmg armor + 3 dmg hp
1 dmg armor
2 threaded - 2 dmg armor + 2 dmg hp
3 threaded - 3 dmg armor + 3 dmg hp
4 threaded 4 dmg armor + 4 dmg hp
1 hit, 1 dmg armor
+ 83 dmg armor

100 dmg armor + 14 damage hp in 1 sec.

20 armor + 66 hp remaining.

Bladestorm vs MoN, Orkboy, Broken Armor or Gaunt:

All 100 rounds hit:

1 dmg
2 threaded - 2 dmg + 2 dmg hp
3 threaded - 3 dmg + 3 dmg hp
4 threaded - 4 dmg + 4 dmg hp
1dmg
2 threaded - 2dmg + 2 dmg hp
3 threaded- 3dmg + 3 dmg hp
1 dmg
2 threaded- 2 dmg + 2 dmg hp
3 threaded- 3 dmg + 3 dmg hp
1 dmg
2 dmg (headshot)
2 threaded 4 dmg (headshot) + 2 dmg hp
2 dmg (headshot)
1 dmg
2 dmg (headshot)
2 threaded 4 dmg (headshot) + 2 dmg hp
3 threaded 6 dmg (headshot) + 3 dmg hp
72 scattered hits - 72 dmg

78 dmg + 72 dmg = 150 hp damage from 100 rounds.


Important
Bladestorm opens up a window of time to register hits on a target for all other weapons with Bladestorm. So if one Eldar hits you with a shuriken, another can thread off, and extend that window as well. Which makes Bladestorm, an actual storm of blades focused on a single point. (And terrifying)

A Storm Shield, and other invulnerable save mechanics aren't affected by critical hits. Teams can still bring the shield down by weight of fire, but they can't expect to bring down the bearer under accurate fire.

Melee (Chain Sabres)

Now this is different. First, it's a specialist weapon not even available to most SS's. However, it actually has rending unlike virtually everything else that will be in launch, save the Tyranids. Melee atm isn't equipped to handle anything super fancy, so, really, the only thing I can think of is a Yasuo type of jab. A very thin attack that punctures through whatever it hits in melee and deals extra damage, again, rending through armor and straight into the hp of the victim. Without armor, it applies what damage would have been dealt to armor to the hp as well.

What do you think?

The Bladestorm rule should cause Eldar Shuriken weaponry to deal at least 16.7% of its damage through the Target's Armor to their HP, regardless of the Target's Armor Save. Additionally, all weapons with Bladestorm could penetrate a single target or even certain types of cover to deal reduced damage to another target within a short distance. Rending would work the same way as they are the same thing, just with different names.

At 2.3 DMG(system rounds to nearest 1/10th) per Shuriken, it would require 36 Shuriken to deplete the Marine's 66.8 Armor(TT 3+ Armor Save, 4 out of 6), at which point they would have lost 16 of their 40 HP(TT Toughness scale of 1 to 10), requiring 11 more Shuriken to Down them for a total of 47 Shuriken in 1.15-sec.
Comparatively, the Marine's 13.6* DMG Bolter would require 4 Bolts to break the Dire Avenger's 50.1 Armor(TT 4+ AS) and 4.7(deals +10% HP DMG due to Strength being 1 higher than Eldar Toughness) of their 30 HP(3 Toughness), needing 2 more Bolts to Down them for 6 Bolts in 1.25-sec.

*S3(Imperial Guardsman/Human) is the basis for minimum 10 DMG.
Using a system that rounds to nearest 1/10th, S1 must be at least 3.4 that causes S3 to be 10.2 and thus S4 to be 13.6.

Storm Shields would be able to stop all damage so long as their Power Field held, afterwards the weapons able to penetrate to start whittling away at the Marine.

So if I read that correctly, I can assume that every Shuriken launched will deal 16% of its damage directly to the target's health.

I see that as a viable mod option to the weapon, but not the standard.

I'm going to assume you'd not want to see a fair / skill based critical hit system since there's not really any mention or even critique of it.

Well, the question is: how small is this grouping. Because if Shuriken catapults will have spreading like Stormbolter, it would be hard enough to make any damage at all. But i like idea of this mechanic.

We shall summon great gods of balance here and ask their opinion.
@BrentEllison @NoahWard

It seems way too complicated to work and I also dislike randomn elements in a skill base game, probably some extra damage on headshot will be all we got (if anything).

Why make it so difficult? Just let rending weapons do more damage to armour to represent the holes the armour takes as the shuriken punch through. The armour drops faster but you still need to kill the occupier of said shredded armour.

Because Rending weapons, and Shuriken's are not necessarily anti armor weapons. They don't really have a good ap value, or a high strength value like a plasma gun has. They have a chance to do critical damage and preform better than a plasma gun in that brief moment (Autowound vs High % to wound), but otherwise they aren't necessarily any better than a bolter / storm bolter.

A good point about accuracy. Well see what the devs say hopefully, but I'd at least hope that Shuriken's would be accurate up to a certain point before falling nearly hopelessly off at maximum range.

Another weapon that could definitely see play is the Elite from the RTS; Ranger Long Rifle. The only true sniper rifle in the game. I think everyone would agree that headshots would be critical hits triggers, but to what extent would that critical hit be?

Don't Space Marines Scouts also have sniper rifles? I doubt we'd see some Tacticals with sniper rifles, but BE could still add some scouts as Elites (and that wouldn't bother me at all).

About Sniper rifles, to stick to the RTS, a Ranger sniper rifle's headshot shall not One Shot; yet according to the TT and DoW2 trailer, it should. I think it should and let the bullets be subject to gravity (for SB, regular Bolter, PG, HB ....) just like the Planetside 2 engine.

On the other hand and for shuriken weapons, I do like the idea of successive succesful hits that would deal tons of damage, but I don't quite get how you would implement this for multiple shooters.
In order to let such a thing happen (multiple shooters on the same unfortunate target dealing threading hits stacking onto each other) would be to trigger a passive on hit on the target, just like the melta currently does.

http://forum.eternalcrusade.com/threads/on-giving-constructive-alpha-feedback.49739/

Bullet point two in Brent's "giving alpha feedback" thread. Defining the problem is more important to us than the suggested solution. I'm not even exactly sure what the problem is that we're trying to solve. It looks like a lot of thought and work when into the suggestion and I love the enthusiasm but it seems to me to be solving a hypothetical future problem. For us I think the valuable part of this post is "I think Rending would be a cool unique feature of Eldar weaponry." Followed by "I will buy so much stuff in the Rogue Trader Store if you add it".

Michael is building the Eldar weapons now so let's see if he chimes in here with any input.

Scouts do indeed have snipers, but scouts won't be in the game on release. I did count them in the OP.

I agree that snipers shouldn't 1 hit. But I'd be ok with a bolt action speed sniper rifle that deals 90% of someone's hp on a headshot.

That's A-ok.

@NoahWard , my suggestion aside, the real intention about what we're getting at is two seperate issues: "Eldar are highly skilled in the lore and have critical hits in TT to represent this. How do we implement this across a faction that fairly incorporates player skill and reduces or eliminates the random chance factor of most RPG critical hit tables?" The other question is actually DJPenguins and I agree with him:

"Should the Eldar have a higher skill floor as well as a higher skill ceiling?"

My answer is yes, and the example I gave in the OP I hope gives more clarity as to how this could be represented. If Eldar players can "thread shots" they're proving their skill and will be rewarded for it. Failure to do so isn't a punishment, but the results will be predictably slower. The random "crit chance" will be determined on the actual skill of the player to consistantly land shots in the same place.

High risk, high reward and positive feedback as Brent has said since the begining. Edit: In any case, thanks for the response. I can't wait to hear what Michael has to say aboutthis as well!