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Fragmentation Damage
Blast and fragments are separate damage channels. Blast uses TNT-equivalent charge mass and its own distance curve. Fragments use the explosive's casing, metal mass, distribution and speed. TNT mass still matters: more charge relative to metal gives fragments more initial energy and lets them wound farther away. It no longer multiplies a preset fragment radius.
FragType selects a construction profile. Each profile supplies typical metal
mass when the definition has no Mass, average effective fragment mass,
fragmentation efficiency, peak injury damage and energy retention. Mass is in
grams; when present, the model estimates metal as projectile mass minus the
TNT-equivalent charge mass. This is an approximation because TNT equivalence is
an energy measure, not necessarily the physical filler mass. FragMetalMassg
can supply metal mass when that approximation is poor. FragCount can specify
the effective count for preformed balls or cubes. A positive
ExplosiveMassTNTg or ExplosiveMassTNTKg is required to create fragments.
The effective fragment count is approximately metal mass divided by the preset's representative fragment mass, times its effective fraction. Effective count excludes fragments too small, too slow or trapped in the casing to make the modeled injury. The charge-to-metal ratio gives a bounded launch-energy factor. A bullet's authored muzzle velocity can raise that factor for forward airburst subprojectiles. Larger fragments retain energy longer. The model uses an exponential distance loss for retained injury severity.
For a fully exposed player, expected arrivals use fragment count times a
1.2-square-metre target area, divided by the pattern's solid angle and
distance² + 1. Partial block cover reduces the expected arrivals. The chance
of one or more effective hits is 1 - exp(-expected arrivals). Damage is the
configured peak multiplied by that chance and the retained-energy fraction.
This is expected damage, applied deterministically; it does not simulate
each fragment or imply that a real casualty radius guarantees a kill.
The server queries targets only out to the distance where expected unarmoured
damage falls below 1 HP, then applies maxExplosionRadius. This derived radius
and effective fragment count are shown on the item tooltip. That reach is a
gameplay and performance threshold, not the farthest possible travel of a stray
fragment. Terrain cover is measured from the true detonation point. Armour
greater than 0 mm blocks the fragment HP
channel on vehicle parts.
The casing presets are LOW_FRAG (thin offensive grenade), STD_FRAG (cast
hand grenade), SLEEVE_FRAG (jacketed grenade), HIGH_FRAG (finely fragmented
defensive grenade), IED_SHRAPNEL (added loose metal), HE_SHELL (shell or
mortar), HE_GRENADE (fragment-optimized 40 mm grenade), GP_BOMB (bomb),
THICK_CASE (heavy penetrator), AIRBURST_AP (small antipersonnel airburst),
and PREFORMED (deliberately formed balls or subprojectiles). DEFAULT has no
fragment burst.
FragPattern is independent of casing type:
| Pattern | Directions | Example |
|---|---|---|
RADIAL |
All directions | Ordinary hand grenade or HE shell |
HORIZONTAL_BAND |
Within 8 degrees above or below the burst's horizontal plane | S-Mine 35 |
FORWARD_FAN |
About 60 degrees wide and 16 degrees high in the explosive's facing | M18A1 Claymore |
FORWARD_CONE |
5-degree half-angle cone along travel/facing | 35 mm AHEAD |
Moving bullets use their velocity direction; stopped explosives use their
facing. A target outside a directional pattern receives no fragments from it,
although blast can still hurt it. Fragment spark particles follow the same
pattern. For a visible fragment envelope of at least 4 blocks, the client shows a
brief, capped sample of small sparks starting near the fireball edge; these are visual
cues rather than individually simulated fragments. The S-Mine uses
FragBurstHeight 1: when the space above it is clear, the complete detonation
happens one block higher.
A blocked rise keeps the detonation at the grenade position. The clearance check
ignores only the block containing the mine, so a mine resting slightly inside a
floor block can still rise while a solid block above it still prevents the rise.
This abstracts the bounce without simulating a second moving mine entity. All
falloff, cover, sound and visual effects use the selected detonation point.
The old FragRadius, FragLethalRadius and FragIntensity definition keys
are no longer read. Use casing mass, effective count or pattern to tune a
construction, and FragDamage only when injury per hit truly differs from the
preset. The S-Mine's former per-item radius override has been removed. Built-in
nuclear devices have no ordinary casing-fragment burst.
- U.S. Marine Corps M67 training gives 5 m killing and 15 m casualty-producing radii. Those are not guaranteed results for one exposed person.
- U.S. Army M18A1 documentation describes its forward fan, while the Army's portfolio lists more than 700 steel balls.
- U.S. Army medical history describes roughly 350 balls, rods or scraps in the S-Mine.
- Rheinmetall's AHEAD brochure gives 152 subprojectiles, a 500 g payload and the forward cone distribution for PMD062.
These sources guide the construction and qualitative balance targets. The fragment size, drag and injury values in the presets remain gameplay estimates.