Case of Tau TX78 Sky Ray Gunship

[0t0]

Recently I did some test in debug mode and was puzzled with how Sky Ray behaves in some situations. My calculations didn’t match game results so I did another test trying to find where the gap is as I suspect there is a bug.
Sky ray gunship is Tau tier 6 vehicle. It is armed with Twin-Linked Smart Missile System as main “gun” and two Seeker missiles as extra actions with CD of 5 turns. By default, Sky Ray has following traits: Skimmer, Tank and Vehicle, all of which we have no interest here, but following three are important:

Fire Team: Increases the ranged accuracy when adjacent to an allied vehicle or monstrous creature. +1 ranged accuracy. Though, this one we didn’t used during testing.

Velocity Tracker: Increases the ranged accuracy against flyers. +33% accuracy vs flyers.

Networked Markerlight: Increases the ranged accuracy and ranged damage reduction bypass. The unit's attacks do not benefit from or consume Target Acquired. +1 ranged accuracy and +100% ranged damage reduction bypass

Above three traits make this unit perfect fit for air defense role. There is unique Tau feature/trait Velocity Tracker that is applied to vehicle instead of more common attribute of the weapon. You will find many examples of guns having trait Skyfire but I believe Tau is only exception to this rule where similar trait is given to the vehicle/battlesuits. Bringing this here, as I was somehow expecting that all Sky Ray weapon base stats are already affected with this trait. We’ll see it is not the case.

Specs of the Twin-Linked Smart Missile System are following:
Damage: 2
Attacks: 4
Penetration: 1
Accuracy: 11 (92%)
Range: 2
Traits:
Heavy: Reduces the accuracy after moving.
Ignores Cover: Ignores the ranged damage reduction of the target unit.
Homing: Does not require line of sight.
Twin-Linked: Increases the accuracy.

Target 1: Webway gate, fortification, armor 6 no ranged damage reduction
Damage= 11/12*2*4*(12-5)/12=4.27 game result 4.3, so we are good here
This confirms base data for the gun is for “normal” targets, in other words not affected by Velocity tracker buff.

Target 2: Neophyte Hybrids, infantry, armor 4, 6 member group with 2HP each, can activate shrouded for +33% ranged damage reduction. First try is without shrouded.
Damage = 11/12*2*4*(12-3)/12=5.5 and game result is the same.
We get same result even after activating Shrouded or by putting this unit in ruins or even by combining two for 66% ranged damage reduction, Sky Ray gun is bypassing this.
Here I have dilemma, is this due to gun trait Ignores Cover or because of Networked Markerlight as both are dealing with the same subject. In any case we see that gun is not affected by ranged damage reduction.

Target 3: Umbra, flyer, armor 6 and permanent trait Shrouded giving +33% ranged damage reduction.
Damage = 11/12*1.33*2*4*(12-5)/12=5.69 and game result is 3.8. This is big disconnect.
We have seen that ranged damage reduction is not relevant hence there is no multiplier in formula for Umbra Shrouded debuff. Multiplier 1.33 is used to increase accuracy against flyer as per velocity tracker.

Target 4: Doom Scythe, armor 7, no ranged damage reduction trait
Damage = 11/12*1.33*2*4*(12-6)/12= 4.87 and game result is 3.3, big disconnect again but here we have no ranged damage reduction factor to take in account. If Doom Scythe activate jink result will remain the same.

I have no explanation where the disconnect is in my calculation and game results.
What bothers me is where Sky Ray is getting 3 points of accuracy for its weapons. Smart Missile System base accuracy is 8, but on Sky Ray it is 11. +1 can come from Networked Markerlight but what about other two. Similar is with Seeker missiles. They are accuracy 6, but on Sky Ray 9.

Seeker missile test
Damage 6
Attacks 1 (x3)
Penetration 4
Accuracy 9 (75%)

Webway gate
Damage = 9/12*6*3*10/12= 11.25 and game result is 11.2
Neophyte
Damage =9/12*2*3=4.5 and game result is 4.5
Umbra
Damage= 9/12*1.33*6*3*10/12=14.96 and game result is 10
Doom Scythe
Damage= 9/12*1.33*6*3*9/12= 13.46 and game result is 9

To get game results by attacking flyers we would need to use reduced accuracy (10 for Smart Missile System and 8 for Seeker missiles) and no accuracy buff (+33%) as it looks Networked Markerlight buff for accuracy was not applied as well buff for Velocity trackers was also not applied too.

Example for Doom Scythe
Damage=8/12*6*3*9/12=9

[Jey]

Here I have dilemma, is this due to gun trait Ignores Cover or because of Networked Markerlight as both are dealing with the same subject. In any case we see that gun is not affected by ranged damage reduction.

I mean... Both? It doesn't really matter which one "works" if both give the same bonus right?

What bothers me is where Sky Ray is getting 3 points of accuracy for its weapons. Smart Missile System base accuracy is 8, but on Sky Ray it is 11. +1 can come from Networked Markerlight but what about other two.

Weapons do not have base ranged accuracy. It comes from the unit.
SkyRays have 8 base ranged accuracy +2 from Twin-Linked +1 from Networking Markerlight, so 11 for the main weapon.
8 base ranged accuracy +1 from Networking Markerlight for the Seeker Missile, so 9.

To get game results by attacking flyers we would need to

Add a *0.67 multiplier.

All flyers apply a hidden -33% ranged accuracy to all weapons that hit them that are not:
- From an air unit
OR
- With the Skyfire trait.

This hidden modifier is known to affect accuracy (and not another stat), because you can see very low accuracy weapons (e.g fully demoralized Tankbustas) go red when targetting a flying unit (but not one when targetting a land unit)

It's very surprising for me that:
- Velocity Tracker does not ignore this penalty (as Skyfire does, although admittedly the flyer trait specifically only mentions Skyfire)
- The penalty is not cancelled by Velocity Tracker (As usually all modifiers are additive so -33% from flyer and +33% from Velocity Tracker should compensate.)

The conclusion is that this -33% ranged Accuracy against flyers seems to be a rare multiplicative modifier, applied after all additive modifier to accuracy.

[0t0]

Ah, as always good catch Jay.
I forgot to include penalty for attacking fliers in my calculations assuming sky ray is by default anti air.
Adding this it looks things works fine.
Thing is Velocity tracker doesn’t simply negate flyer penalty but add on top of that making it overall different multiplicator.
So, without velocity tracker you apply 0.67 in formula, but if you have it then it is 0.67(penalty)*1.33(vel. Tracker) what is 0.89 and then all calculations and game result match.
It works same on Sky Ray as well on battlesuites with velocity tracker module installed.

Thanks for helping me demystifying this strange setup.

Originally posted by Jey:

This hidden modifier is known to affect accuracy (and not another stat), because you can see very low accuracy weapons (e.g fully demoralized Tankbustas) go red when targetting a flying unit (but not one when targetting a land unit)

Does red mean below 2? It should be 4*0.67(broken)*0.67(flyer)= 1.8. If flyer is also vehicle does Rokkit Launcha get +2 for penetration or it is just against tanks.

[Jey]

Does red mean below 2?

Red means exactly 2. Accuracy can never be below 2.

. If flyer is also vehicle does Rokkit Launcha get +2 for penetration.

It does. The trait says "vehicles" not "tanks" (like the Tank Commander does).

[0t0]

Thanks, I didn't know min accuracy is capped at 2.
After playing this for years still there are new things to learn!
Have a nice day man.

[Golden Xan]

I haven't gone through every step of the calculation, and honestly I would probably not remember everything perfectly from the top of my head, but there are a few things I can add to this.

On some cases, weapons *can* have a base stat set to them on the weapon itself, though this is rare. On a mod I'm working on, I'm also setting every accuracy to be on the weapon itself, not the character.

*Almost* all calculations are done sequentially and multiplicatively, which means that if you have any one element that is below 100% or higher than 100%, it's going to affect everything else. But there are a few exceptions. The idea is that this confirms what Jey said about the Velocity Tracker bonus interacting with the Air unit hidden accuracy penalty.

The bonuses and penalties are only calculated additively when they are done by attribute increase, instead of a percentage. For example, +2 Accuracy is equivalent to roughly 16,66% increased accuracy, which gets rounded to 17%, again *MOST* of the time (but there are exceptions).

I believe you actually *can* lower accuracy below 2, because I have been able to get accuracy to 0, and it makes it so the unit causes zero damage, which makes it unable to target enemies at all. And if you make it so they have 0 accuracy against specific targets, such as flyers, they can attack everything but that target.

On my mod, Golden Tooltips, the interface is revamped to help clarify how many of these bonuses work. I was brought here by a user who commented on it asking about this issue you were facing.

[Jey]

Originally posted by Golden Xan:

On some cases, weapons *can* have a base stat set to them on the weapon itself

I do not believe any vanilla weapon has accuracy on it.

The bonuses and penalties are only calculated additively when they are done by attribute increase, instead of a percentage.

This is wrong.
Get a Malanthrope and Spirite.
Use both of their -50% attacks skill on a termagant.
-> The Termagant has exactly 0 attacks (you'd expect it to be 0.25 if done multiplicatively)
Make the Termagant walk on a Skull Altar
-> The termagant has exactly 0.17 attack (you'd expect it to still be 0 if it was done additively for same type and multiplicatively for opposed signs)

For example, +2 Accuracy is equivalent to roughly 16,66% increased accuracy

I'm unclear what you mean by that, but it's definitely misleading.

On a 4 accuracy unit, +2 accuracy is equal to a +50% increase on the final damage dealt.

I believe you actually *can* lower accuracy below 2

No, you cannot.

because I have been able to get accuracy to 0

You can fix accuracy to 0, which is done on the Doomsday Ark main cannon for example with the High Power/Low Power trait.
You cannot lower it.
For example if you made a trait that gives -100% accuracy, the unit would still have 2 accuracy.

[Golden Xan]

On a 4 accuracy unit, +2 accuracy is equal to a +50% increase on the final damage dealt.

An Accuracy of 4 allows the unit to cause 33% of its base weapon damage, if there are no other effects. In this case, +2 Accuracy would add 17% of its base weapon damage, leading it to cause 50% of the base weapon damage, which is also +50% of 33% ( 33% / 2 = 16,5%, rounded to 17% ).

If the character had an Accuracy of 8, +2 Accuracy would increase the damage from 66% to 83% of the base weapon damage, which is not 50% more of 66% (that would be 99%, rounded to 100%).

This can be confirmed by just reading the numbers of various units in the game with different Accuracy values. You will see units that have Accuracy 8 as an attribute have 66% accuracy in terms of weapon damage, and Accuracy 4 has 33%, and Accuracy 10 have 83%, and so on.

You can fix accuracy to 0, which is done on the Doomsday Ark main cannon for example with the High Power/Low Power trait.
You cannot lower it.
For example if you made a trait that gives -100% accuracy, the unit would still have 2 accuracy.

Got it, thanks for clarifying.

[Jey]

Originally posted by Golden Xan:

You will see units that have Accuracy 8 as an attribute have 66% accuracy in terms of weapon damage, and Accuracy 4 has 33%, and Accuracy 10 have 83%, and so on.

What you meant then was that increasing accuracy by 2 gives +17 points of percentage on accuracy.