Modified EDU for Improved Battle Realism in RTW

[phalanx_man]

Hello Modders and Gamers.

I have been an avid fan of RTW since January 2009 when I first played the game.   Since then, I was introduced to Rome Total Realism which, for me, took the game to a new level with its realistic battles, skins, historical unit additions and historical backgrounds.   This prompted me in 2010 to do my own research on ancient arms and armour.   In the course of this research I saw where the game's combat mechanics could be further improved and, in fact, made equivalent to actual historical battles in terms of casualty rates and battle duration.   I also began to think that the combat parameters themselves could (and should) be more standardized to reflect, for example, sizes of shield, types of armour and the skill of the troops as a reflection of their level of training.   Up until now, the values of armour, shield, skill and attack seemed to be a rather ad-hoc affair rather than systematic.   

These changes would all be made in the EDU (export_descr_units.txt) file.   Aradan has written an excellent tutorial of the EDU file which was invaluable to me in this work.  Please refer to it here if you wish to me more familiar with all the parameters in EDU:

The Complete EDU Guide, by Aradan (July 20 2007)
http://www.twcenter.net/forums/showthread.php?111344-The-Complete-EDU-Guide

The EDU file that this particular mod uses incorporates all of the many changes that have evolved with my research and battle testing of combat parameters in the RTW battle engine.   If you are used to the RTW vanilla battles you will see a distinct difference here, and it is my sincere hope that you enjoy the battles even more.

Ahowl11 has asked me to give some background as to what changes have been introduced and I will do so here.  Before I do however, let me say that there is a lot of information on things I have discovered and I don't want to overwhelm anyone with too much information.   Thus I will rather try to summarize the key changes rather than make this an all encompassing writeup.

Also, I have broken up my work of combat parameters into four separate phases, two reports of which I have completed (and posted in the http://www.twcenter.net/forums/)  and two more of which my work has been completed but I have yet to post the formal reports.

The reader is welcome to go to the above forum and see my first two works of combat parameters, the links of which are here:

RTW BATTLE MECHANICS: Part I – A Study of Combat Parameters (August 02 2010)
http://www.twcenter.net/forums/showthread.php?377804-RTW-BATTLE-MECHANICS-Part-I-–-A-Study-of-Combat-Parameters

RTW BATTLE MECHANICS: Part II – Equalization of Skeleton Lethality (January 18 2014)
http://www.twcenter.net/forums/showthread.php?638418-RTW-BATTLE-MECHANICS-Part-II-–-Equalization-of-Skeleton-Lethality

Part I will give the reader a good overview on the subject and Part II will explain why the values of lethality (the last parameter on the EDU line "stat_pri" and "stat_sec") have been changed to those values you see in this EDU.

The result of subsequent work is also included in this EDU but, as I have not yet written up parts III and IV, I will try to summarize here the highlights of what I had done.   I hope to shortly give a more full account of those changes when I do write parts III and IV and post them on the forum.

The remaining work includes the following:

Part III:  A Systematic Approach to Standardizing Combat Parameters

The basic thing I did here was define quality of troop types and, using that quality, standardize the values of Armour, Defence Skill, Shield, Attack, Base Morale, Recruitment (training) time, Recruitment and upkeep costs. 

III-A: Troop Types and Quality:


TROOP        DEF     TRAINING  ATTACK
QUALITY     SKILL   TIME         MODIFIER  (NOTES)
=========================================================================
Untrained   07-09     0            -2        (can train multiple units in one turn)
Levies        10-12     1            -1         (minimal training)
Regular      13-15     2             0         (standard training)
High           16-18     3            +1        (Well-Trained)
Sub-Elite    19-21     4            +2        (Superbly trained)
Elite           22-24     6            +3        (Elite level training)
Ultra-Elite  25-27     8            +4        (Best-of-the-best, only Spartans & Hoplite Elites)


Note that I use Marcus Camillus' 4 turns-per-year, so levies have 3 months basic training, standard troops 6 months (which is typical even for today's armies), and so on...   The Ultra-Elite group only exists for those soldiers that take the best of existing elite troops to form their units (Hoplite Elites) and Spartans since they are trained pretty much from birth to be nothing but soldiers.   Since I could not model this in the game, I simply put a very long training time to represent this.

As I have needed a numerical parameter to measure the quality of troops, I chose Defence Skill which I am using to represent overall combat skill in my system.   Thus, as we shall see, every other combat parameter will be based on this value.   From here on, I will refer to Defence Skill merely as "Skill".


III-B: Morale:
A VERY important stat, Base Morale is represented by the first parameter in the EDU line "stat_mental".   
Inspired as I was by the words of Vegetius,

"The courage of the soldier is heightened by the knowledge of his profession."

in this system, stat_mental is set EQUAL to skill, with some adjustments for certain troop types as follows:


Most Units:                         Base Morale = Skill
Harsh Environment Units:  Base Morale = Skill +1 (Harsh Living Bonus)
Roman Infantry Units:       Base Morale = Skill +2 (Roman Discipline Bonus)
Zealot Units:                     Base Morale = Skill +3 (Religious Zeal Bonus)
Berserk Units:                   Base Morale = Skill +4 (Berserk Bonus) 
Spartans: (special)           Base Morale = Skill +5 (Spartan Discipline Bonus)
All Phalangites:                Base Morale = Skill -4 (Penalty)

For the other 2 parameters in the stat_mental line, we have the following:

SKILL     DISCIPLINE VALUE   TRAINING VALUE
===========================================
01-12     LOW                     UNTRAINED
13-15     NORMAL                     TRAINED
16+     DISCIPLINED     HIGHLY TRAINED


III-C: Armour

HEAD PROTECTION:
Skull Cap = +1 (or other misc types that are not hard but reasonably offer some protection)
Metal Bell-Type = +1 (No Side/Cheek Protection - even with ear and rear neck prot) , Ex = Carthaginian, Iberian
Metal Full-Open Face wi Side Protection = +2 , aka Thracian style (Macedonian, Thracian, Illyrian & Roman)
Metal Partial-Open Face wi Side prot = +3 , aka Chalcidian style (ATG Spartan Hoplites)
Metal Closed Face = +4 ,  aka Corinthian style (Elite Hoplites), Full Thracian (Bastarnae, Thracian Infantry)

LEG PROTECTION:
Greaves = +2 , 
Note = Roman Troops only used one Greave and it was on the shield side.

BREAST/MID-BODY PROTECTION:

Thin Cloth/Padding = +1.  Deemed to exist under ALL armours – soft mails need cloth, breastplate needs padding.
Thick Cloth/Padded Cloth = +2* on its own (no extra +1 bonus for cloth underneath other armours).
--------------------------------------------------------------------------------------------------------------------------------------

The following Armours have the value indicated IN ADDITION TO +1 for the Cloth or Padding underneath.

Padded OR Soft Linen Armour OR Animal Furs = +2
Small Breastplate = +2   

Leather Mail (non-hardened) = +3 
Quilted Linen = +3 
Medium Breastplate = +3 

Hardened Linen or Studded Leather = +4   

Hardened Leather = +5   

Linthorax (Lamellar Reinforced Hardened Linen) = +6

Normal Chain Mail = +7     

Full Chain Mail (cover hips, groin AND thighs)  = +10 for Men, +12 for Horse/Camel/Elephant*

Normal Scale Mail = +8 

Full Scale Mail (cover hips, groin AND thighs)  = +11 for Men,  +13 for Horse/Camel/Elephant*

Bronze (Full) Breast Plate with Leather waist = +9

III-D: Shield Value:
I had initially done this based on my research into the Legionnaire's shield dimensions and made the following assumption/definition. 

Shield Value = Number of square meters of total shield area x 10

The Roman Shield was one of the largest at approximately 0.8 square meters, yielding a shield value of 8.

For other shields, I simply based it on a VISUAL comparison to the Roman shield.

Approximating based on visual determination the following general rule can be used for shield values:


RELATIVE   SHIELD
SIZE          VALUE     EXAMPLES
==============================================================
SMALL         2           Peltast Shields
MEDIUM      4           Barbarian Swordsmen
LARGE         6           Barbarian Spearmen
HUGE          8           Roman Legionnaires *


* Hoplite shields are given a value of 8 even though by their size they are only a 6.   This is because, in the hoplite formation, each hoplite is defended from the sides as well by his fellow hoplites to either side.  So, by the nature of the FORMATION, it is EQUIVALENT to having a larger shield.   Other shields that have excess curvature which in turn affords some extra protection have small bonuses as well.


III-E: Weapons

For weapons, I started with the most basic weapon and its most basic value as used in RTR.   The typical value for low trained spearmen is 8, so I began with that as a basis.   Don't forget, the actual damage value increases +1 with each level of quality, which is in turn based on skill value.   The sword values I calculated using a method I derived which is a little long to explain here but I will elaborate on it when I post the Part III writeup to the forum.   

Suffice it to say that the base weapon values here are calculated/estimated based on the following criteria:

(a) how easy it is to get around a shield (short weapons are better, so swords are better than spears),

(b) weapon momentum when thrust/swung at an opponent (heavier = more damage,  2-handed > 1 handed),

(c) the number of means of attack the weapon has (2 edges is better than one, 2 edges and pointed is better than 2 edges with blunt point, so Xiphos is superior to Kopis or Barbarian sword)

(d) swordsmen emphasis on thrusting over slashing is more damage (so Roman Gladius** is better than Xiphos)


                       BASE
MELEE                    ATTACK       WEAPON        UNIT
WEAPON                VALUE    EXAMPLES     EXAMPLES
--------------------------------------------------------------------------------------------------
Spear (1-Handed)    8    6'-9' Spear    Hoplites & Spearmen
Pike (2-Handed)   10*          12' Xyston     Phalangites, Short Pike Phalanx
Pike (2-Handed)   13*    21' Sarissa   Phalangites, Long Pike Phalanx

Sword (1-edge)    9     Kopis       Eastern Swords & Arabian Scimitar
Barb Long Sword   10                       Barbarians (not including Iberians)
Sword (2-edge+p)   11              Xiphos        Greek Swordsmen, Iberians
Sword (2-edge+p)   12**     Gladius       Legionnaires
Short Sword              6                                Some Horsemen & Archers
Knife                    5                       Some Skirmishers

Axe (1-Handed)    9                                 Cilician Pirates
Pick-Axe (2-Hand)   12*                               Germanic Berserkers (Vanilla)
Rhomphaia              13*                       Thracian Infantry, Bastarnae
Falx                   16*                        Falxmen
Club                     5           Mod Specific

MISSILE               BASE
WEAPON             VALUE    RANGE         UNIT EXAMPLES
-----------------------------------------------------------------------------
Bamboo Javelin      8      25m                Any Indian Elephant Units
Javelin               10      25m                Skirmishers, Peltasts
Pilum               11*    15m                Legionnaires
Arrow                 3      120-170m       Archers (Range 120m – 170m)
Sling Stone            1      150-180m       Slingers (Range 150m – 180m)


* means Armour Piercing Attribute ("ap" for melee weapon or "ap thrown" for missile weapons)

** Roman Legionnaires emphasized thrusting over slashing, which gives their attacks much more chance to hit unarmoured areas.   This is the chief reason behind the relative superiority on the Roman method of sword fighting over their Barbarian neighbours.   Note that even though the Xiphos is double edged and pointed (like the Gladius), the troops using it (Greek swordsmen and Iberians using the same Gladius Hispanicus as the Romans) did not have the same emphasis on thrusting, so the same equivalent weapon in their hands does less damage than a Roman Legionnaire would do.   


III-F: Training Units  (optional but recommended)

Since the more skilled a unit is, training is longer with more phases ( basic, advanced etc).   Just like comparing Navy Seals to Marines to Regular Army, the training is more rigorous and longer.    Also, for units that take the best of other units (Hoplite Elite) or that train from Birth (Spartans), hereby referred to as Ultra-Elite, the only way I could represent it was to add more training time.   For these, 8 may not be enough – I am considering raising it to 10 or 12 instead.


                          TRAINING BUILDING                         MINIMUM
SKILL         CIVILIZED                BARBARIAN               SETTLEMENT
=============================================================
07-11    Muster Hall               Muster Field              Town
11-14    Militia Barracks         Hall of Warriors         Large Town
14-16    Barracks                   Hall of Heroes           City
16-19    Provincial Barracks   Regional Barracks      City
19+    Royal Barracks         High King's Barracks  City


I added to my EDB (buildings) barbarian equivalents to Provincial and Royal barracks and made City the highest required settlement size.  I did this mainly so that Barbarians were on a level playing field for recruiting with respect to "civilized" factions (since barbarians settlements cannot go beyond city).     Furthermore, it seemed logical that once a settlement reached city status, it should be able to train any types of troops – being any bigger should not make any further difference.


Part IV:  Modified Defence System for Flanking and Rear Attacks

I had noted, during some campaign play-testing that I had not addressed one important issue in my part III work – and that is what I will call the "excessive flanking effect" that some of you may have seen.

In one test battle,  I matched 1 unit of SPARTANS against 2 units of MILITIA HOPLITES and (surprise) the SPARTANS were DEFEATED if one militia hoplite unit engaged from the front and  the other attacked from the rear of the Spartans.   When you look at the numbers it made no sense (nor historically either).   To give you an idea of the numbers, Spartans were ATT=12 ARMOR=15 SKILL=25 SHIELD=8 and militia hoplites were ATT=7 ARMOR=5 SKILL=12 SHIELD=8.   So, according to the RTW battle engine 2 units of 7/25 could easily defeat one unit of 12/48 !!!  (And not just defeat, they EASILY defeated them).   Something was drastically wrong.   

The problem that I failed to realize was that the 3 attributes of defence (Armour, Def-Skill and Shield) were applied differently by the RTW battle engine.

- ARMOUR applies to all f directions relative to a soldier – front, left flank, right flank and rear.
- DEF SKILL only applies to front and partially to right flank (it is supposed to represent parrying the enemy's weapon with your own) and does not apply to missiles attacks.
- SHIELD only applies to front and partially to left flank (using the shield to block enemy blows) and applied double for missile attacks from the front.

However, in a real battle, if a second enemy unit comes at (say) your unit from behind or in a flank attack, the soldiers at the rear or flanks are not going to simply stay facing "forward" but will obviously wheel about to face their new attackers (at least one rank or file would anyway).   In fact, this is true VISUALLY in RTW since you can see ANY units will have the men in the flank/rear ranks turn about to face the new enemy soldiers to their side/back.   Thus, it stands to reason that these soldiers SHOULD STILL have their SHIELD and SKILL credited to them - but they don't.   This confused me earlier on as I figured if they are turning around they must be getting all their combat stats as well.

I understand that RTW probably thought that it would somehow compensate for the fact that once a unit is flanked (or surrounded) that there has to be SOME penalty (or effect) to that unit - which is true... BUT, that penalty should be in the form of LOSS OF MORALE, NOT a penalty to their fighting ability.

How it SHOULD have been (to be realistic) is as follows:
- ARMOR should apply all around for both melee and missiles
- SKILL should apply all around for melee, but not apply at all to missiles
- SHIELD should apply all around in melee, apply double from missile attacks from the general "front" of the unit and not apply to missiles from any other direction.

So, in our example, the Spartans had a Defence value of 48 from their FRONT, but ONLY 12 from their rear !!!

Since the way the battle engine uses these numbers is hardcoded, there was no way I could change that outright BUT I could compensate by taking defence skill and REDSITRIBUTING it between armour and shield values.   In this way, the TOTAL defence (from the front) would remain unchanged BUT there would be a much smaller penalty to attacks from the flanks or rear, which is more realistic.

I decided to redistribute the defence skill value in the following way:
- Most Infantry Units: 80% to Armour (rounded up) and remainder to Shield
- Hoplites: 75% to Armour (round up) and remainder to Shield
- Phalangites: 25% to Armour (round up), 25% to Shield (round up) and leave remainder as Defence Skill
- Infantry with no Shield: 100% to Armour
- Cavalry Units where Rider has a Shield:  80% to Armour (rounded up) and remainder to Shield
- Cavalry Units where Horses Crest comprises the Shield: 100% to Armour
- Elephants, Chariots and their Riders:  100% to Armour
- Skirmisher Units: Same as Most Infantry Units above
- Pure Archer/Slinger Units:  New Armour = 6+old armour value
- Specialist Archer Units: Treat as Skirmishers above

So, in our above example, the values of Armour/Skill/Shield change as follows:
Spartans go from DEFENSE(orig) = 15/25/8 = 48 to DEFENSE(new) = 34/0/14 = 48
Militia Hoplites go from DEFENSE(orig) = 5/12/8 = 25 to DEFENSE(new) = 14/0/11 = 25

And thus now, the battle to the FRONT of the Spartans is unchanged in terms of kill rates BUT from behind, instead of the militia hoplites attacking a Spartan rear defence of 15 they are now attacking a 34.

When I reran that same test battle, the new result was as follows.  Both militia units were defeated ! (as would be expected).   When both militia units routed they had 110 men left (took 370 casualties), and they had killed 38 Spartans, resulting in a kill ratio of about 10:1 – a FAR more believable ratio considering the Spartans fighting prowess.   Also, the militia hoplites had killed 15 Spartans from the front and 23 from the rear which is also good since it shows not too much of a difference but still notable due to the shield value not applying to the rear side.

Note,  the reason I didn't simply transfer ALL the skill value to armour is twofold:

(1) The greater the skill of the soldier, he should be equally more skilled in how effectively he uses his shield
and,
(2) Shield effect against MISSILES is double from the front, and again, more skilled troops should be able to better defend against missile volleys from the front than less skilled ones.

The other thing I had to do was tweak all the missile attack values to bring missile casualties back in line to what I had before because now the armour value is higher and the shield value (which is doubles vs. missile attacks) is much higher effectively, I was getting no casualties from missile attacks even against unarmoured and unshielded troops.

I also had to tweak all the weapons that had the ARMOR PIERCING attribute, since this attribute works by counting only half of the targets armour.  But now that the armour value was so much greater, ap-weapons were getting a huge bonus increase from before which I had to compensate for to bring back in line.   

In the test battles (and in-campaign battles as well) I have run since this change, this modification has worked out very well in my opinion.

I hope you all think so too.

Best Regards and Happy Gaming,

Sincerely,
Phalanx_man.

[ahowl11]

Thank you so much phalanx_man I appreciate it.
I cannot wait to release 0.5 to the team, I just need to do a few more things, but in the meantime hopefully all BETA testers read this and know what to look for in regards to battles.