Engine Upgrades Analysis

[Merudo]

I made this table to evaluate the benefits of increasing engine by one.

As you know, increasing evade by a number, say 10, will have more dramatic effects the higher your evade currently is. So, a ship with 0 evade will receive 10% less hits than before the upgrade, while a ship with 50 evade will receive 20% less hits than before, and a ship with 90% evade will receive 100% less hits as it will now evade every attack.

Here are two tables describing these effects. Here, "5.9 less hits" means that by upgrading the engine to this level, you will receive 5.9% less hit than you did at the previous level.

Manned, crew has no experience

Engine - Evade - EHP - Upgrade vs previous level
1 - 15 - 35.3 - takes 15% less hits, survives 18% longer
2 - 20 - 37.5 - takes 5.9% less hits, survives 6.3% longer
3 - 25 - 40.0 - takes 6.3% less hits, survives 6.7% longer
4 - 30 - 42.9 - takes 6.7% less hits, survives 7.1% longer
5 - 35 - 46.2 - takes 7.1% less hits, survives 7.7% longer
6 - 38 - 48.4 - takes 4.6% less hits, survives 4.8% longer
7 - 41 - 50.8 - takes 4.8% less hits, survives 5.1% longer
8 - 45 - 54.5 - takes 6.8% less hits, survives 7.3% longer

Manned, crew has full experience

Engine - Evade - EHP - Upgrade vs previous level
1 - 25 - 40.0 - takes 25% less hits, survives 33% longer
2 - 30 - 42.9 - takes 6.7% less hits, survives 7.1% longer
3 - 35 - 46.2 - takes 7.1% less hits, survives 7.7% longer
4 - 40 - 50.0 - takes 7.7% less hits, survives 8.3% longer
5 - 45 - 54.5 - takes 8.3% less hits, survives 9.1% longer
6 - 48 - 57.7 - takes 5.5% less hits, survives 5.8% longer
7 - 51 - 61.2 - takes 5.8% less hits, survives 6.1% longer
8 - 55 - 66.7 - takes 8.2% less hits, survives 8.9% longer

As you see, the biggest upgrades come at level 1, level 5 and level 8.

[Levgre]

Whatever math you used, I believe is very off, or irrelevant. Dodge rates give a 'proportionally' larger amount of missed shots early on, but will give a linear increase in % shots dodged..

I.E. 10-15% is 50% more dodged shots (from 2 of 20 to 3 of 20)
15-20% is 33% increase in dodged shots (from 3 of 20 to 4 of 20)
20-25% is 25% increased in dodged shots ( from 4 of 20 to 5 of 20)

As you see the (x of 20) of shots you dodge is still linear, so each dodge upgrade gives an equal defense benefit. 30% is 30% less total damage from missiles on average, 50% dodge is 50% total less damage from missiles on average.

[Twinge]

Ah, ye olde 'dodge is linear / dodge has diminishing rewards / the more you have is better' argument.

The best way to think of this (whatever game you're talking about) is in terms of effective HP. Going from 0% to 10% dodge raises your effective HP from 30 to 33.3 (or 11%). Going from 40% to 50% evasion increased EHP from 50 to 60 (20%). So while you're increasing dodge by a flat 10% in both cases, it's almost twice as effective in the latter case. For a more extreme example, going from 0%->1% increases EHP from 30 to 30.3, while going from 98%->99% increased EHP from 1500 to 3000 (that's double the effectiveness for only 1%!)

For FTL specifically, here's a cost-effectiveness chart, assuming normal values for piloting/engine bonuses and including the cost of power:

Code: Select all

 LEVEL	COST	DODGE	EFFICIENCY
 2			10	6.579	4.56
 3			15	7.042	5.68
 4			30	7.576	7.26
 5			40	9.091	7.70
 6			60	5.769	15.60
 7			80	6.122	17.97
 8		  120	8.889	16.87

Cost effectiveness roughly halves from Level 5 to 6 - Level 5 is the standard point to aim for, and anything past that is a luxury.

[Levgre]

The usefullness of EHP is limited in FTL, because often case the concern is not really hull health, but whether you take 'any' damage versus tough opponents (which involves, of course, whether your shields have been overwhelmed). Taking 5 damage vs the flagship can lead to a breakdown in your defense/offense as a whole, and lead to a lot more damage, if not a loss.

Similarly, you want to prevent as many hull hits as possible as you progress through systems, as any damage = scrap spent in repairs.

It's hard to talk about systems in terms of 'luxuries', because you will very often have to choose some systems to upgrade more than would be ideal, depending on circumstances. Sometimes post 5 engines is still a worthwhile and preferred upgrade option, to ensure your shields hold and avoid bad strokes of luck vs the flagship if you expect a prolonged battle.

[Merudo]

Whatever math you used, I believe is very off, or irrelevant. Dodge rates give a 'proportionally' larger amount of missed shots early on, but will give a linear increase in % shots dodged..

I.E. 10-15% is 50% more dodged shots (from 2 of 20 to 3 of 20)
15-20% is 33% increase in dodged shots (from 3 of 20 to 4 of 20)
20-25% is 25% increased in dodged shots ( from 4 of 20 to 5 of 20)

As you see the (x of 20) of shots you dodge is still linear, so each dodge upgrade gives an equal defense benefit. 30% is 30% less total damage from missiles on average, 50% dodge is 50% total less damage from missiles on average.

I don't think that is a very helpful way to think about it. Going from 2/20 dodged shots to 3/20 dodged shots won't make much of a difference, but going from 18/20 dodged shots to 19/20 dodges shots will make you survive twice as long...

[Merudo]

I also added EHP information thanks to Twinge.

Also note that I disagree with the following,

The usefullness of EHP is limited in FTL, because often case the concern is not really hull health, but whether you take 'any' damage versus tough opponents (which involves, of course, whether your shields have been overwhelmed). Taking 5 damage vs the flagship can lead to a breakdown in your defense/offense as a whole, and lead to a lot more damage, if not a loss.

Let's imagine that each time an enemy shot lands, you have probability p > 0 of having a critical breakdown in your defense/offense as a whole (here p could be 20%, 50%, 100%, etc).

EHP then has another interpretation: if you have say 30% more EHP by upgrading dodge, then it will take 30% more time on average before such a critical breakdown occurs.

This holds for all values of p.

[Levgre]

I also added EHP information thanks to Twinge.

Also note that I disagree with the following,

The usefullness of EHP is limited in FTL, because often case the concern is not really hull health, but whether you take 'any' damage versus tough opponents (which involves, of course, whether your shields have been overwhelmed). Taking 5 damage vs the flagship can lead to a breakdown in your defense/offense as a whole, and lead to a lot more damage, if not a loss.

Let's imagine that each time an enemy shot lands, you have probability p > 0 of having a critical breakdown in your defense/offense as a whole (here p could be 20%, 50%, 100%, etc).

EHP then has another interpretation: if you have say 30% more EHP by upgrading dodge, then it will take 30% more time on average before such a critical breakdown occurs.

This holds for all values of p.

What math/reasoning are you using to link EHP to 'breakdown'? You are trying to calculate very different things. If you are just taking into account say missiles, the odds of avoiding a 'breakdown' (one hit) increase linearly with increased dodge rate, and EHP is far from linear.