Gore

When a body dies in EngineD it either leaves a corpse or comes apart: chunks fly away from the shot, bounce, bleed and settle, and the blood they leave stays on the walls and floor for the rest of the level. All of it is decided by the simulation, so a replay paints every stain in the same place.

What a killing blow decides

Coming apart where it is hit

A body comes apart in the direction it was hit. Its chunks leave from its centre, away from the attacker, fanned out in a spiral so they never stack on one line, and as fast as the weapon's force says (a body type can insist on a minimum). Which chunks a body throws is that body's own list: meat, organs, a head. The engine names no creature and no chunk; the game supplies them.

A shotgun is judged as one shot. A body killed by the first pellets waits for the rest of the volley that is still arriving, and only then asks whether it was overkilled, so pellets that land after the kill still count. Pellets that miss do not.

A body whose type lists breakable joints goes further. Its remains come apart at those joints into pieces of its own skeleton, each with a cut end, and a shot that lands on a corpse's arm can take the arm off. A body type may also be built to explode: torn apart, it explodes at once; left as a corpse, it explodes when that corpse is finally shot to pieces.

The life of a chunk

Chunks in flight, drips and settling

A flying chunk tumbles, bounces off walls and floors, and leaves a splat on the surfaces it strikes. A chunk that bleeds sheds drops as it moves, scattered a little so they spray rather than fall in a line. Every few drops lands as a real mark; the rest stop where they hit and fade.

Once a chunk stops it is held at rest: it is not moved, gets no gravity and costs the simulation nothing per tick. Only a real cause wakes it, and the engine keeps a short list of them:

• A blast throws it again. It bounces and paints afresh, so a pile under repeated rockets keeps spreading.
• Another chunk landing on it knocks it about.
• A moving platform or door shoves it out of the way, so it slides and falls rather than letting the slab pass through it. A chunk riding a lift is carried, not woken.
• The floor going away under it lets it fall.

Chunks float in liquids by the same rule as the corpse they came from. A creature can eat a chunk, and a game can let a settled chunk turn into a pickup. By default a chunk lasts eight seconds and then goes; a game can keep them for ever.

Corpses

A corpse is a body of its own, separate from the creature that died, so the dead creature can finish its death while the corpse is already lying there. It can be shot, blown up, pushed and crushed, and it takes as much punishment as the living body had health. Dead flesh answers two hits differently from living flesh: a blast lands twice as hard, and poison does nothing at all.

A body type can describe a ragdoll: a chain of limbs that flop and drape as the body falls. The engine ships none; the game describes one for each body that wants it. Ragdoll limbs are physics run for the picture, so the engine keeps them on a short leash. Nothing in the simulation waits for a ragdoll to settle, limbs never block a shot, and a limb may push a chunk but a chunk never pushes a limb.

The picture also has an allowance for how many ragdolls it moves at once, sized so the frame rate holds. Past the first limit the oldest bodies stop touching each other and rest only on the level; past the second they are laid still for good.

Blood and footprints

Every lasting blood mark is a patch the simulation owns, whatever made it: a wound, a chunk striking a surface, a drop landing, a joint giving way. A wound that crosses a threshold throws blood along the shot onto the wall behind the victim, up to twelve metres away, and the harder the wounds so far, the larger the patch. A body in the way does not catch it; only the level does.

Walk through a patch and your feet take its colour for a while. Each patch can hand out a limited number of sets, so a pool does not print for ever, and the prints are the patch's colour, never the walker's own blood.

1. Step inFeet over a fresh patch take its colour.
2. WalkA print every stride, facing the way the body faces, on walls too.
3. Run outThe set fades after a while; wading through a liquid washes it off.

Caps: what gives way

The engine's default is to keep everything. Patches, prints and corpses stay for the life of the level, and the engine pays for that by making settled things cost nothing rather than by deleting them. Every cap is an option a game can set, with one exception that ships switched on.

Dropping the newest marking drop instead of the oldest is deliberate: the oldest are the ones about to land. A per-body cap is spent before the world's, so a rat coming apart never clears away a boss's chunks.

8 s

a chunk's default lifetime

12 m

how far wound blood can reach the wall behind

Engine defaults as of 2026-10-22; a game can change each of them.

Who decides what

Gore follows the engine's one split. The simulation decides whether each chunk, drop, patch, print and corpse exists and where it is; the adapter decides only how it looks. That is why blood from a wound is a real patch and not a picture: if the adapter could decide that a stain exists, the game's state would depend on who was watching.

How the pictures are made, and how a level full of settled gore stays cheap to draw, is on the rendering and effects sheet. What decides a kill in the first place is damage, and the whole path of one bullet is in life of a shot.

• DamageThe one door every hurt passes through, including the killing blow.
• Weapons and projectilesWhere a blast's push and a weapon's force come from.
• Level machineryThe lifts and doors that shove settled gore aside.
• Rendering and effectsHow blood, chunks and marks are drawn.