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Pulse Cannons vs shields
04-16-2015, 04:02 PM
Post: #1
Pulse Cannons vs shields
I am confused I guess about current rules for IPC. Say I have a ship with 7 IPC2. These do 48 damage at optimal range. Times 7 is 336. 30% vs shields, means 100 damage per round to shields, no? Ok, there is shield blocking and shields 3 blocks, as far as I know, 3% of the 100 = 97 left. Shields should absorb the 97, and, I should also hit structure as bonus damage. Not sure of the recharge rate of shields 3, but, without energy controller or modulation, should not come anywhere even remotely close to 97. Yet, I see very little damage per round vs shields, something like 10 points or so. Seems to vary slightly by range which it should of course. But even at point blank range, very little shield damage. Is blocking per weapon perhaps (not total)?

So, clearly, I am totally wrong on IPC damage. So, can someone explain the detailed math here? I can see that ALL IPC does not work well, just not sure why. Seems like it should easily knock the shields down in very little time once in range of starbase. Starbase had 840 shield points. No engineers.

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04-16-2015, 10:37 PM (This post was last modified: 04-16-2015 11:15 PM by Diebo.)
Post: #2
RE: Pulse Cannons vs shields
(04-16-2015 04:02 PM)sfatula Wrote:  I am confused I guess about current rules for IPC. Say I have a ship with 7 IPC2. These do 48 damage at optimal range. Times 7 is 336. 30% vs shields, means 100 damage per round to shields, no? Ok, there is shield blocking and shields 3 blocks, as far as I know, 3% of the 100 = 97 left. Shields should absorb the 97, and, I should also hit structure as bonus damage. Not sure of the recharge rate of shields 3, but, without energy controller or modulation, should not come anywhere even remotely close to 97. Yet, I see very little damage per round vs shields, something like 10 points or so. Seems to vary slightly by range which it should of course. But even at point blank range, very little shield damage. Is blocking per weapon perhaps (not total)?

So, clearly, I am totally wrong on IPC damage. So, can someone explain the detailed math here? I can see that ALL IPC does not work well, just not sure why. Seems like it should easily knock the shields down in very little time once in range of starbase. Starbase had 840 shield points. No engineers.

I pulled out Mr. Empirical Method (and Excel) and did some tests. I took a starbase 1 with shield 4 (1120 total). No engineers or other system slots. I sent a battleship with 3 engines/2 thrusters (to keep it close) once with 4 IPC3, and once with 4 Laser 3.

Laser 3: Each shot should do 24 damage close up against Shields. Shield 4 blocks 8 per shot (shields block 2/4/6/8 per level, not percent).

On each round, it looks like 36 damage was getting through (the numbers dropped from 1067 to 1031 to 995 to 959... each 36 apart). With 4 Laser 3 that means each one was doing (36 / 4 = 9) 9 damage. So:

24 damage - 8 blocked by Shield 4 = 16 damage for each x 4 = 64 damage total per round (expected).

This implies that the shield recharge rate is 64 (expected) - 36 (actual) = 28 per turn or 28 / 1120 = 0.025 = 2.5% shield recharge rate.

As expected, IPC3 was similar to Laser 3 (77 x .3 = 23.1 base damage against shields vs 24 for laser 3 ). It did slightly less damage, but if you can afford it, no reason to not to put all IPC3.

In your example, 7 IPC 2 vs Starbase 1 with Shield 3:

Each IPC2 at max does 48 x 0.3 = 14.4 or 14 damage vs shield
Shield 3 blocks 6 of that damage, so 14 - 6 = 8.
With 7 IPC2, you should be doing roughly 7 x 8 = 56 damage/round (expected).

Shield 3 has 840 base; with a recharge of 2.5% that would equal about 21 per round. Your 56 damage gets cut (56 - 21 = 35) (actual).

Now, assuming that you aren't optimally in range, your IPC could be doing between 48-18 (x 0.3 = 14 to 5 range - 6 blocked) damage. Battleships are slow and turn poorly. Firing happens at the end of movement, not at closest position to target.

If you are only doing 10 damage, that would imply that your effective attack range is a little bit farther out. Sometimes you are probably right next to the starbase, other times you are turning and farther away. Try with 3 engines and 2 thrusters; you should get closer to that max value.

What you are really up against in this case is the shield recharge rate. You need more firepower to cut through that 21 points of recharge. Once the shields go down that IPC will rip through the starbase (and it will have no more structure left). A single Plasma 3 at range would add an extra 27 x 1.5 = 40.5 damage - 6 blocked = 34 damage per round. But you certainly don't need plasma. Just more ships. Shield recharge is fantastic when there isn't much firepower. It quickly becomes meaningless against concentrated fire.
And for those curious, this implies:

1. Improved Energy Controller doubles shield recharge. That suggests from 0.25% to 0.5%. Or 56 per turn for Shield 4 on a Starbase 1.

2. I tried a Shield Modulation Unit on the Starbase 1 with Shield 4 versus the 4 Laser 3 example I used. It blocked an additional 8 damage total (or 2 per Laser 3). In other words, instead of blocking 8 damage per attack with shield 4, with SMU you block 10 damage. Not sure about how it works with Shields 1-3.

3. In our example with a Shield 4 on a Starbase 1, IEC gives you an extra 28 recharge. SMU blocks an extra 2. This implies that if you are being attacked by less than 14 weapons (28 / 2) shield recharge is better, if you have to choose. Except that darn nebulae thing, and most people trying to take on a Shield 4 starbase 1 come with more than 14 weapons (warlord 2 is commonly available by then). My money for versatility is on SMU. A shield that is up and blocks additional damage is better than one that is down and recharges faster!

With Shield 4 and SMU, it should be proof against Keep Long Laser 3 attacks (5 damage x 2 = 10, and you would block 10).
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04-17-2015, 03:03 AM
Post: #3
RE: Pulse Cannons vs shields
So, forgive me for checking.... But, here is my source of info:

http://www.chimerasw.com/starbaseorion/f...p?tid=2309 Note post 10 where Roc says it is percentage now. Then there is this, which appears incorrect but is more recent:

http://www.chimerasw.com/starbaseorion/f...p?tid=2593 Post 3 from Anthee.

I see you did not simulate shields 3. I cannot find anyone who documented the shield recharge rate by shield class. Seems unusual that shields 4 would have a rate of 2.5%? What are the rates by shield level? You are assuming that shield 3 has the same recharge rate? I thought I saw a message where it was different by level, but can't find it now. It all seems like guessing to me by simulation (and providing ranges of values that seem to fit the simulation). I had thought that Roc posting was pretty much fact, but maybe not.

I would love to see, documented by Roc, what is shield blocking by shield level, specifics for shield modulation and improved controller, by shield level if appropriate, and, shield recharge rate by level. It appears lot of people have opinions as to what those are. ANd the questions come up a lot in the space bar.

Try 7IPC2 with no CE or thrusters, vs starbase and see if you also note it will not kill the starbase. With no weapons, it would eventually, but after a full turn, not even close. Structure is down to almost 0, but, hundreds of shield points left. It doesn't seem right to me, but, maybe shield recharge is higher than I think. And blocking may be higher than Roc indicated in his post. Glad to know that it's per weapon firing, not all weapons in total. Still, would be great to at last see all the numbers documented. No? And I don't see how you can know what range an IPC is at from the battle screen while running it, is there some trick?

I don't use all IPC battleships any more except by accident. This question also came up during a 4v4 game with lots of guys like Grr, Adam, Sloth, Ch0c, me, Praedos, Jaba. We really couldn't for sure figure out how the ipcs could not kill a fairly wimpy sb. We saw it several times, are were just curious to see if there might be a bug here. Maybe there isn't.

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04-17-2015, 03:37 AM (This post was last modified: 04-17-2015 03:58 AM by Diebo.)
Post: #4
RE: Pulse Cannons vs shields
Well, I looked through the Whipping Post and I couldn't see where shield blocking was changed to percent.

Roc, are you sure you didn't think that you made that change, and just didn't? Because my numbers really come out looking clean in that regard.

If it was changed to percent, then that means that 1 point was being blocked. Which then means that shield recharge is monstrous, and I don't think it is. My money (currently $0) is on Roc thinking he made that change, but the code actually is still 2/4/6/8.

RE: 2.5% recharge rate. Yes, I did assume a flat rate for all shield recharge. The bigger the shield, the more recharge there would be. There wouldn't be a logical reason to change that (and if there was a different, I would think it would be 1/2/3/4% or something). It wouldn't be hard to test with Shield 3 and a starbase, but I am not curious enough to do so right now. I am pretty confident in this value, and that it is consistent between shields. Not too often that the number comes out exactly at a reasonable value like 2.5% for each of 5 laser attacks.

Anyway, unless told otherwise by Roc I think my analysis stands. And even if my base assumption on shield blocking is incorrect (8 points vs 1), there are few enough variables to play with. Those variables:

1. The amount of damage that you should be doing. 1 laser 3 close up should do 24 damage to shields.

2. The amount of damage blocked. For shields 4, it is either 8 points or 4% (1 point for Laser 3 - whoopee!).

3. The amount of damage actually witnessed during combat at close range (use thrusters to keep close). With Laser 3, 36 points were getting through with 4 Lasers, or 9 points each.

4. Shield recharge rate. It is either 2.5% for Shield 4 (and likely all shields), or something much greater.

It is easy to test this stuff, if so inclined. The empirical method is strong.
Ok I lied, I was curious.

I tried 4 laser 3 against a Sheild 3 starbase 1.

The shields went from 695 to 641 to 595 to 541 to 495 etc. etc.

The actual damage was 46, 54, 46, 54.

If Shield 3 blocks 6 points x 4 lasers, it should block 24 points total.

If the Recharge rate is 2.5% on 840 hitpoints, 21 points should be recharged per turn.

4 Lasers should do 96 damage (4 count x 12 damage at close x 2 shield bonus).

So there should be an average of 96 - 24 (blocked) - 21 (recharge) = 51 damage.

And the average of 46, 54, 46, 54 is 50 damage. Maybe a rounding error, maybe the lasers weren't always at 100 percent close range.

The calculations seem to hold for Shield 3 too.
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04-17-2015, 04:15 AM (This post was last modified: 04-17-2015 04:16 AM by rocco.)
Post: #5
RE: Pulse Cannons vs shields
Keep in mind, damage is a linear interpolation between the two ships. The only way to get absolute maximum damage is to occupy the exact same position as the other ship (which I don't believe it possible).

Current shield blocking code looks something like this:

Code:
// Shield completely negate a portion of the damage
float block = ([self shieldDamageBlocking] / 100.0f);
baseDmg -= ceil(baseDmg * block);
shieldBlockLog = block;

Which basically says take the calculated shieldDamageBlocking value, treat it as a percentage [0, 100], subtract it from the damage of the weapon (baseDmg), rounding up.

shieldDamageBlocking value code looks like this:

Code:
- (float) shieldDamageBlocking
{
    float mod = 0;
    
    if([ShipSystems containsObject:TECH_SHIELD_MODULATION_UNIT])
    {
        mod = 4;
    }
    
    float shieldBlock = (float)(internalShieldBlocking+mod);
    
    if(shieldBlock < 1.0f && (shieldsDamage < internalShieldPoints))
    {
        shieldBlock = 1.0f;
    }
    
    return shieldBlock;
}

Which basically says, the blocking value will be the internalShieldBlocking value, +4 if your have shield mod unit, and if you have any shields won't be less than 1.

internalShieldBlocking is:

TECH_ENERGY_SHIELDS_I: 2
TECH_ENERGY_SHIELDS_II: 4
TECH_ENERGY_SHIELDS_III: 6
TECH_ENERGY_SHIELDS_IV: 8


So, all said and done:

Without shield mod unit:
2% blocking
4% blocking
6% blocking
8% blocking

With shield mod unit:
6% blocking
8% blocking
10% blocking
12% blocking


I don't recall when specifically when we changed to percentage-based vs flat reduction. Due to the magic of source control, I know it was sometime before July 29, 2013.
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04-17-2015, 04:54 AM (This post was last modified: 04-17-2015 05:01 AM by Diebo.)
Post: #6
RE: Pulse Cannons vs shields
Thanks for sharing Roc.

Empirically, things were working out pretty well for the old shield block method.

What is the shield recharge rate?

I tried another example that doesn't make a lot of sense. 8 Laser 3 versus a Shield 4 Starbase 1 (1120 hitpoints).

Each round I was doing 112 damage, or 14 per laser. If 8 percent is blocked, that should be 2 points per laser. I was right next to the starbase (thrusters), and the damage was exactly 112 per round for 8 rounds.

The expected damage would be 12 for close up laser, x2 for shield = 24, -2 for blocking, or 22 x 8 lasers = 176. The only other variable is recharge. Which means that it is recharging on average 22-14 = 8 x 8 = 64/round. Or 5.7 percent of 1120. The problem is, for my example with Shield 4 vs 4 Laser 3, the recharge rate there is 4.6 percent). Unless I am missing a variable somewhere.

The only thing I can think is that I was really 11 damage away every single turn (or 10 or whatever) in terms of range. But knowing the recharge rate would help calibrate that.
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04-17-2015, 06:02 AM (This post was last modified: 04-17-2015 06:03 AM by rocco.)
Post: #7
RE: Pulse Cannons vs shields
Code:
float rechargeRate = (internalShieldBlocking*5);
    
if([ShipSystems containsObject:TECH_IMPROVED_ENERGY_CONTROLLER])
{
        rechargeRate *= 2.0f;
}

shieldsDamage -= rechargeRate;
if(shieldsDamage < 0)
{
  shieldsDamage = 0;
}

Shield recharge rate is the internalShieldBlocking * 5; so

Without energy controller:
10
20
30
40

With energy controller:
20
40
60
80

So those are shield points recharged per round (shields 4 + energy controller heals 80 shield points each round).
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04-17-2015, 07:20 AM (This post was last modified: 04-17-2015 07:21 AM by Diebo.)
Post: #8
RE: Pulse Cannons vs shields
Thanks Roc.

So let's re-examine E45y's case:

7IPC2 do 48 (max) to 18 (min) damage each.
Against shields (30%), they do 14 to 5 damage (rounded down).

Shields block 14 x 6% = minimum of 1.

Recharge is 30.

Ok, if he is at max IPC range, 7 x 5 = 35 damage - blocking (7 x 1) = 28 damage, minus recharge of 30 = -2 damage. No damage from keeping long.

If he is right next to the starbase, he should do 7 x 14 = 98 damage - blocking (7 x 1) = 91 damage - recharge (30) = 61 damage. That would take 13 turns to bring the shield down (if you could get close enough to do full damage).

I just ran a test case with 7IPC2, 3 engines, 2 thrusters against a SB1, Shield 3. Shield damage dropped from 797 to 750 to 703 to 656 to 609 to 555 to 508 to 461 to 414... On average, 47 damage went through. And the starbase (without any HA/RB) died.

47 damage + 30 recharge + 7 blocked = 84 total, or 12 for each of the 7 IPC2. 14.4 is max. Looking at the battleship weapon chart, it is bouncing in the middle of the short range zone. I can believe that 12 is the value.

So it seems to work - except E45y said he was only doing 10 damage. Where are you on the damage chart? My engines/thrusters probably made a big difference.
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04-19-2015, 03:23 PM (This post was last modified: 04-19-2015 03:27 PM by sfatula.)
Post: #9
RE: Pulse Cannons vs shields
Yep, it was likely no thrusters would be my guess as almost never would I be at point blank range. Thanks for clarifying Roc! Finally get shields figured out now. Shield mod not as tough as I thought. Sounds like the math makes sense. Mixing in laser + a gauss is awesome though! Once shields are down, the gauss kills it instantly since the IPC has already reduced structure to almost 0.

I was previously not aware that blocking was per weapon.
This means a gauss 3 can do damage against shields. 2 vs 1 blocked leaves 1 each. However, would take a lot of them to overcome the recharge.

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