Rebalancing Civ4: RtR Mod

[Krill]

I play devils advocate more than is good for me, TBH.

If someone that can actually understand the code wanted to suggest changes and methods of change to collateral that would probably be the best way to justify changes to Trebs...but it's a lot of work and changes a lot. But I need to sleep now, gotta be up in 6 hours.

[WilliamLP]

I also think (from sims) that the Barrage promotion is better than its reputation for a unit likely to die attacking a top defender, because it actually increases collateral damage, whereas the CR line does not.

[SevenSpirits]

In your hypothetical, if a treb is getting 50% odds, why do you even need siege at all? Just kill the thing with knights or CR maces or something at even better odds.

Have you even used trebs?

Here, I just put a longbow in a 20% culture city and checked odds with a treb, a knight, and a maceman. Each unit was granted 5xp, so the longbow has CG2, knight has C2, and the other two have CR2. Guess what the odds are?

Treb: 71.1%
Knight: 65.5%
Mace: 27.0%

A catapult btw (with CR2) gets 8.7% there.

[SevenSpirits]

Catapults are a powerful unit too, but cheaper and for more than 1 purpose.

Thankfully no one is complaining that catapults are underpowered.

[WilliamLP]

Have you even used trebs?

As I said before, just against the comp. Other than that it's all theorycraft.

Interesting stats though! And I'm sure you know all the following, but I think a lot of people here don't know it:

This is where another non-intuitive part of the Civ 4 combat mechanics come into play. Modifications to the strength of an attacking unit (other than the Combat series) don't actually change the strength of that unit, but it all gets added up and applied to the defender.

The "obvious" calculation:
Mace strength is 8 * 1.45 (CR2) = 11.6
Treb strength is 4 * 2.45 (CR2 + 100% inherent) = 9.8

So you'd think the mace would be stronger but it's not because the real calculation is:

vs Mace, the defender bonus is 0.90 (CR2 + 25% inherent + 20% culture) - 0.45 = 0.45. So the bow's strength is 6+2.7 = 8.7 (vs the mace's 8)

vs Treb, the defender bonus is 0.90 - 1.45 = -0.55. The game uses a different formula when the number becomes negative, dividing by 1 plus the absolute percentage (yielding the correct limits and avoiding division by zero for -100%) which gives 6 / (1.55) ~= 3.87 (vs the treb's 4).

So that "explains" it though I certainly wouldn't have suspected Trebs were stronger attackers by eyeballing the numbers!

Does that make me want to build them? I don't know! They still have a lot of problems to overcome like their cost, being useless for defense and stack battles, and the fact that city defenders in their era are probably stronger than this, for fortification and hills if nothing else.

Sorry if this is too off the topic of this thread, but I like learning these things.

[BaII]

Also keep in my that a Treb doesn't have to "fully win" a battle. I believe once the defender is below a certain point in HP that it would simply retreat so a treb would get even better odds since it doesn't require as many hits to win the battle.

[Ruff_Hi]

I also think (from sims) that the Barrage promotion is better than its reputation for a unit likely to die attacking a top defender, because it actually increases collateral damage, whereas the CR line does not.

I seem to remember that Barrage I is a worthless promo for a treb because the increase gets rounded away. Barrage I is +20% collateral? Thus a cat goes from 5 to 6 while a Treb goes from 4 to 4 (4 x 1.2 rounded down).

[NobleHelium]

I also think (from sims) that the Barrage promotion is better than its reputation for a unit likely to die attacking a top defender, because it actually increases collateral damage, whereas the CR line does not.

Most cats are promoted to Barrage.

[SevenSpirits]

I seem to remember that Barrage I is a worthless promo for a treb because the increase gets rounded away. Barrage I is +20% collateral? Thus a cat goes from 5 to 6 while a Treb goes from 4 to 4 (4 x 1.2 rounded down).

The number that gets multiplied by 1.2 is:

10 * (3x + y + 1) / (x + 3y + 1)

x = base strength of collateral attacker
y = base strength of collateral damage victim

It seems unlikely to me that trebs in particular would have rounding errors here.

Example: treb hitting lb:

10 * (3*4 + 6 + 1) / (4 + 3*6 + 1) = 8.3, rounding down to 8.

1.2 * 10 * (3*4 + 6 + 1) / (4 + 3*6 + 1) = 9.9, rounding down to 9.

So you could try to optimize for specific base strength collateral target units, and it will be different for treb vs cat, but I doubt anyone has shown a mathematical propensity for 4 to be a worse x input into that formula than 5, for similarly low values of y. (It might be, but I think that would be a coincidence. I think that whoever said that just didn't know how it worked.)

For completeness' sake: The formula above is then multiplied by (100% - target's collateral reduction) before rounding down, so that complicates things further.

[novice]

As has been pointed out the point of Trebs is that they are terrible in the field but good at attacking cities. This is implemented by a low base strength and high city attack bonus. I'd say it works as intended.