Skip to content

Suppression

Suppression fire is one of the defining combat features of 1.13. Vanilla JA2 technically had a suppression system, but it was broken — a character could only be suppressed once or twice in the entire game. Headrock investigated the code, fixed it, and rebuilt it as part of HAM (Headrock's Assorted Modifications); HAM was merged into the main 1.13 code in March 2009, and the system has been part of standard 1.13 ever since. In current releases it is enabled by default (SUPPRESSION_EFFECTIVENESS = 75).

The short version: bullets that crack past a soldier's head scare that soldier. Enough of them and he loses Action Points, loses morale, shoots worse, ducks, and eventually curls up on the ground unable to act. This works on your mercs exactly as it works on the enemy.

How it works

Every bullet that passes close to a character can add suppression points to that character. Points accumulate over the turn, and it doesn't matter who fired the bullet — friendly fire scares people too.

Each character also has a tolerance value (between 1 and 18 by default) that represents how hard they are to rattle. When an attack ends, the game compares the suppression points inflicted against the target's tolerance. Suppression beyond what the target can tolerate produces:

  • AP loss. The main effect. The victim loses Action Points and can be driven into negative AP, which is subtracted from their next turn as well.
  • Morale loss. Suppressed characters lose morale, which in turn lowers their tolerance against further suppression — and enemy soldiers whose morale collapses may flee.
  • Shock. See below.
  • Stance drops. Characters who lose enough AP automatically drop from standing to crouched to prone, if they have the AP left to do so.

A character whose entire next turn has been eaten by negative AP is pinned down — the game announces it on screen (with the default 100-AP scale this happens around −80 AP). A pinned enemy is helpless for a whole turn and can be assaulted safely. The INI file itself summarizes the doctrine: suck out the enemy's APs so he can't move or fire back — and note that the AI will try to do the same thing to you.

Shock and cowering

Suppression shock is the lingering, psychological part of the system. AP loss from suppression also hands out shock points (up to MAX_SUPPRESSION_SHOCK, default 30), and shock cuts both ways:

  • A shocked character shoots much worse: each shock point costs 5% chance-to-hit on any ranged attack, up to a cap (MAX_CTH_PENALTY_FROM_SHOCK, default 40).
  • A shocked character is also harder to hit — he is hugging the ground. Anyone shooting at him loses CTH per shock point the target has (CTH_PENALTY_PER_TARGET_SHOCK, default 2, capped at 40 by default).
  • Shock can also reduce vision range and/or cause tunnel vision (SHOCK_REDUCES_SIGHTRANGE, enabled by default).

The defensive bonus depends on stance and where you aim: a prone shocked target gets the full protection, while a crouched one is easier to hit — especially in the legs (the divisors in the INI are 1 for prone, and 3/4/5 for a crouched target's head/torso/legs). The penalty also fades at close range: it only applies in full at long range (MIN_RANGE_FOR_FULL_TARGET_SHOCK_PENALTY, default 300 — in the units Headrock's HAM documentation used, 100 equals 10 tiles). Point-blank, a cowering target is easy prey.

A character who takes too much shock starts cowering — you'll see the message "cowers in fear". Cowering characters lose 4 points of tolerance (COWERING_PENALTY_TO_SUPPRESSION_TOLERANCE), so every further burst fired their way hits harder. This is the death spiral you want to put the enemy into.

Shock is temporary: per Headrock's HAM documentation it is halved at the start of each of the character's turns, so a few turns out of the line of fire clears it.

What causes suppression

  • Volume of fire. Each individual bullet passing close by can add a suppression point. Accuracy is almost irrelevant — a 15-round autofire volley that all misses is a great suppression attack. This is what makes assault rifles, SMGs and especially machine guns valuable beyond their raw damage.
  • Stance of the target. In the current code a crouched target has a 1-in-4 chance to shrug off each suppression point, and a prone target gets two such 1-in-4 chances. Standing targets take the full effect.
  • Buckshot. Each pellet has a 50% chance (by default) of counting as a suppressing bullet (BUCKSHOT_SUPPRESSION_EFFECTIVENESS), so shotguns suppress reasonably well up close.
  • Explosives. All blast-type explosives (frag grenades, stun grenades, TNT, mortar rounds…) cause suppression based on distance from the blast center — and the effect reaches beyond the damage radius of the explosion (EXPLOSIVE_SUPPRESSION_EFFECTIVENESS, default 90).
  • Friendly fire. Bullets from your own side suppress your own people too, once the bullet has traveled a minimum distance from the shooter (MIN_DISTANCE_FRIENDLY_SUPPRESSION, default 30). Don't park mercs downrange of your own machine gunner.

What determines resistance

A character's suppression tolerance is based chiefly on experience level and morale, among other things (clamped between SUPPRESSION_TOLERANCE_MIN = 1 and SUPPRESSION_TOLERANCE_MAX = 18). Green recruits and shaken troops fold quickly; confident veterans can walk through fire. On top of that:

  • Nearby friendlies. With NEARBY_FRIENDLIES_AFFECT_TOLERANCE = TRUE (the default), the condition, leadership and experience of friendlies near a character affect his tolerance. Troops hold up better when they are not alone.
  • Movement. Characters gain 1 bonus tolerance point per 5 tiles they move during their turn (TILES_MOVED_PER_BONUS_TOLERANCE_POINT). Soldiers on the move are harder to pin than soldiers sitting still.
  • The Squadleader trait. A merc with the Squadleader trait grants a 20% suppression-tolerance bonus (OVERALL_SUPRESSION_BONUS_PERCENT in Skills_Settings.INI) to himself and teammates within 10 tiles (20 tiles if both wear extended ears).
  • Character/attitude. Per Headrock's "How does it work?" guide, mercs with the Aggressive attitude are a bit harder to suppress than others.
  • Enemy officers. If enemy roles are enabled, an enemy officer (a soldier with the Squadleader trait) grants the whole enemy team a suppression-resistance bonus: ENEMY_OFFICERS_SUPPRESSION_RESISTANCE_BONUS = 10 for a lieutenant, doubled for a captain. Killing the officer makes the rest of the squad easier to break.

Using suppression offensively

  • Bring a machine gun. Long belts or big magazines plus autofire are the tools of the trade. The AI's own rule of thumb is built into the INI: it only considers weapons with a magazine of 30+ rounds for suppression fire. A belt-fed MG with an assistant machine gunner feeding it can hose down an area turn after turn.
  • Fire for volume, not accuracy. Long unaimed bursts at or around the target are fine. Standing enemies in the open are the ideal victims.
  • Suppress, then flank. The INI's own advice: use suppression fire to stop enemies approaching, pin them down, then advance and kill them while they hide. A pinned or cowering enemy can be assaulted at close range, where the cowering CTH penalty disappears.
  • Concentrate fire to force the spiral. Once "cowers in fear" appears, that target has reduced tolerance — follow-up bursts are disproportionately effective.
  • Don't snipe cowerers at long range. A shocked, prone target can cost your shooter up to −40 CTH by default. Either close the distance, use explosives, or aim at the legs of crouched targets.
  • Use explosives to suppress groups. Even a grenade that lands short rattles everyone near the blast.

Autofire and friends don't mix

Under NCTH it is impossible to predict exactly where autofire bullets go. AI soldiers regularly hit their own side when suppressing, and your mercs can do the same — and your own bullets suppress friendly mercs downrange. Keep firing lanes clear before you hold down the trigger.

Defending against suppression

  • Get low and behind cover. Crouched and especially prone characters have a good chance of ignoring suppression points, and the shock they do take makes them harder to hit.
  • Keep morale and experience up. Tolerance comes mostly from experience level and morale. Rested, victorious veterans are hard to suppress; see the starter tips for keeping a healthy team.
  • Stay together and bring a Squadleader. The nearby-friendlies effect and the Squadleader aura both raise tolerance.
  • Keep moving. Movement during your turn grants bonus tolerance, and staying out of the beaten zone is the best defense of all.
  • Rotate shocked mercs out of the line of fire. Shock decays over a turn or two once the bullets stop coming; a merc at −40 CTH is better off crawling away than returning fire.
  • Spread out against explosives — explosive suppression reaches beyond the blast radius.

Watching suppression in-game

With the default settings, hovering over a soldier shows suppression and shock in the tooltip (SOLDIER_TOOLTIP_DISPLAY_SUPPRESSION and SOLDIER_TOOLTIP_DISPLAY_SHOCK in the [Tactical Tooltip Settings] section). If you want more feedback, the [Tactical Interface Settings] section offers:

  • SHOW_HEALTHBARSOVERHEAD = 2 or 3 — the alternative overhead health bar, which additionally shows suppression shock level and current cover.
  • SHOW_SUPPRESSION_COUNT, SHOW_SHOCK_COUNT, SHOW_AP_COUNT, SHOW_MORALE_COUNT (0 = off, 1 = after the damage counter, 2 = above the soldier) — per-attack counters for suppression points inflicted, shock taken, AP lost and morale hits, with SHOW_SUPPRESSION_COUNT_ALT and the SHOW_SUPPRESSION_USE_ASTERISK / SHOW_SUPPRESSION_SCALE_ASTERISK variants controlling how they are drawn.

INI settings

Everything below lives in Data-1.13\Ja2_Options.INI, section [Tactical Suppression Fire Settings] unless noted. Values shown are the current defaults. See the Ja2_Options.INI tour for how to edit the file safely.

Setting Default What it does (per the INI comments)
SUPPRESSION_EFFECTIVENESS 75 Overall power of suppression. 0 = JA2 default, suppression disabled; 100 = fully active; values over 200 are already excessive.
SUPPRESSION_EFFECTIVENESS_PLAYER 100 Extra multiplier for suppression against player mercs (works together with the main setting; 200 would suppress your mercs twice as hard).
SUPPRESSION_EFFECTIVENESS_AI 100 Same, for suppression against AI soldiers.
SUPPRESSION_TOLERANCE_MAX 18 Maximum tolerance a character can have.
SUPPRESSION_TOLERANCE_MIN 1 Minimum tolerance. Don't set MIN above MAX.
NEARBY_FRIENDLIES_AFFECT_TOLERANCE TRUE Condition, leadership and experience of nearby friendlies affect a character's tolerance.
TILES_MOVED_PER_BONUS_TOLERANCE_POINT 5 1 bonus tolerance point per this many tiles moved during the turn.
NEW_SUPPRESSION_CODE TRUE More balanced tolerance calculation; suppression resistance also affects AP loss.
SUPPRESSION_SHOCK_INTENSITY 100 How much shock is taken when under fire (0 disables shock; 200 is a lot).
MAX_SUPPRESSION_SHOCK 30 Maximum shock points a character can carry.
CTH_PENALTY_PER_TARGET_SHOCK 2 CTH lost per shock point when shooting at a shocked target.
MAX_CTH_PENALTY_FOR_TARGET_SHOCK 40 Cap on that penalty (0 = no limit).
MIN_RANGE_FOR_FULL_TARGET_SHOCK_PENALTY 300 Minimum range to the target for the full penalty; closer shots suffer less of it.
CTH_PENALTY_DIVISOR_FOR_PRONE_SHOCKED_TARGET 1 Divisor on the penalty vs a prone shocked target (full penalty).
CTH_PENALTY_DIVISOR_FOR_CROUCHED_SHOCKED_TARGET_HEAD 3 Divisor when aiming at a crouched shocked target's head.
CTH_PENALTY_DIVISOR_FOR_CROUCHED_SHOCKED_TARGET_TORSO 4 …torso.
CTH_PENALTY_DIVISOR_FOR_CROUCHED_SHOCKED_TARGET_LEGS 5 …legs (easiest to hit).
MAX_CTH_PENALTY_FROM_SHOCK 40 Cap on the CTH a shocked character loses on his own attacks (each shock point costs 5 CTH; 0 = no limit).
SHOCK_REDUCES_SIGHTRANGE 1 Vision loss from shock: 0 = none, 2 = vision range reduced, 3 = tunnel vision increased, 1 = both.
COWERING_PENALTY_TO_SUPPRESSION_TOLERANCE 4 Tolerance lost while cowering (fully shocked).
AI_SUPPRESS_MIN_MAG_SIZE 30 Minimum magazine size before the AI considers a weapon for suppression fire (0 = any autofire-capable weapon).
AI_SUPPRESS_MIN_AMMO_REMAINING 20 Minimum ammo remaining for the AI to use a weapon for suppression.
EXPLOSIVE_SUPPRESSION_EFFECTIVENESS 90 Suppression from blast-type explosives, based on distance from the blast center (0 = disabled, 100 = normal). Works beyond the blast's damage range.
NOTIFY_WHEN_PINNED_DOWN TRUE Show a message when a character has lost all APs off his next turn (normally at −80 AP).
MIN_DISTANCE_FRIENDLY_SUPPRESSION 30 Minimum distance at which characters are suppressed by their own side's fire.
BUCKSHOT_SUPPRESSION_EFFECTIVENESS 50 Suppression chance per buckshot pellet (0–100, used by both NCTH and OCTH).

Related settings elsewhere in Ja2_Options.INI:

Setting Section Default What it does
AI_EXTRA_SUPPRESSION [Tactical AI Settings] TRUE Lets the AI shoot more often for suppression under OCTH by faking a minimum CTH of 1 for autofire-capable weapons.
AI_SAFE_SUPPRESSION [Tactical AI Settings] TRUE Additional check so the AI avoids hitting friends when using suppression fire.
ENEMY_OFFICERS_SUPPRESSION_RESISTANCE_BONUS [Tactical Enemy Role Settings] 10 Suppression-resistance bonus for the whole enemy team while an officer is present (value is for a lieutenant, doubled for a captain).

Too much 'Suppression fire!' for your taste?

Some players find AI suppression spam (and the friendly-fire casualties it causes) annoying. The consensus from the Bear's Pit is: don't zero out SUPPRESSION_EFFECTIVENESS — that cripples one of the AI's most important tools — instead raise AI_SUPPRESS_MIN_MAG_SIZE and AI_SUPPRESS_MIN_AMMO_REMAINING (e.g. to 30/30) so fewer AI soldiers qualify to use it, and keep AI_SAFE_SUPPRESSION enabled.

Sources