git:20261001.a2a8f58 to git:20261003.200e3ce

---

name: dayz-physics-engine

description: "Use when: física DayZ, dBody, collision layers, player walks through my object, action/cursor does not appear, EOnContact, TransportHit, thrown/rolling objects, ragdoll, .ragdoll, fall damage, PhysicsSetSimpleDeath, offload physics / reduce server load. Not vehicle authoring: dayz-vehicles; not flight: dayz-aviation."

---

# DayZ Engine Physics (Enforce Script)

Engine-truth reference for rigid-body work in DayZ mods. Every API claim below was verified against

the decompiled vanilla v1.24 scripts; citations are `path:line` relative to the script root (treat

line numbers as ±3 — minor drift between builds). When something common-sounding is missing here,

check section "What does NOT exist" before assuming it exists.

## How to use this skill

The body covers the 90% working set. Three bundled references hold the full deep-dives — load them

only when the task needs that depth:

| Reference | Read it when |

|---|---|

| `references/fisica-engine-deep-dive.md` | full dBody/dGeom/dJoint signatures, raycast family tables, surfaces, drop-physics lifecycle details |

| `references/transport-netsync-vehiculos.md` | anything about why/how vehicles replicate, CarScript damage-by-momentum, Pawn/TransportOwnerState, push-action pattern |

| `references/dano-transporthit.md` | damage pipeline (MDF), EEHitBy chain, the complete TransportHit flow line-by-line, hitzones, armor reality |

| `references/dayz-1-30-ragdoll-and-fall.md` | 1.30 Exp: `.ragdoll` / `RagdollDef`, `PhysicsSetSimpleDeath`, unconscious wake-while-falling, fall-damage `CurveExp` |

## The 11 engine truths (prevent the classic bugs)

1. **A body only collides where it exists.** The player capsule (CCT) is simulated client-side

(hasta 1.29: `3_game/human.c:1397-1418`; desde 1.30 Exp: `exp/scripts/scripts/3_Game/human.c:1426-1452`). A rigid body created only on the server can never block a player —

the client's CCT has nothing to collide with. This is architectural; no layer mask fixes it.

2. **The action cursor sees View Geometry, not physics.** Action targeting uses `RaycastRVProxy`

with default `ObjIntersectView` (hasta 1.29: `4_world/classes/useractionscomponent/actiontargets.c:214-219`;

desde 1.30 Exp: `exp/scripts/scripts/4_World/Classes/UserActionsComponent/ActionTargets.c:255`; default still

`3_game/global/dayzphysics.c:88`). No View Geometry LOD in the .p3d → no action, no

admin-tool selection, regardless of any physics body. Truth #2 still holds in 1.30. (desde 1.30 Exp:

liquid surfaces with no object are also scored action targets at utility 0.01 —

`exp/scripts/scripts/4_World/Classes/UserActionsComponent/ActionTargets.c:532-534`; `ActionTarget` ctor takes `surfaceName` at `:125-138`.)

3. **`dSetInteractionLayer` is GLOBAL.** It edits the world's layer↔layer interaction matrix

(`1_core/physics/physicsworld.c:14-21`); the first parameter only resolves the world. To stop two

specific entities from colliding use the surgical pair-block instead:

`dBlock b = dBodyCollisionBlock(entA, entB); ... dBodyRemoveBlock(world, b);` (`1_core/proto/enphysics.c:116-117`).

4. **Friction/restitution are material strings, not setters.** They come from the physics material

assigned per-geometry (`PhysicsGeomDef.MaterialName`, e.g. `"material/default"` —

`1_core/physics/physicsgeomdef.c:18-24`) and surface definitions (.bisurf / CfgSurfaces). There is

no `dBodySetFriction`-style API (0 matches in all of scripts/). Measured (BenchRE 2026-08-26):

.bisurf `restitution` does not translate into bounce on the native item path — SmallStone dropped

from 5 m onto open-field terrain rebounds 0.02-10 mm (apparent e = 0.009-0.046, n=6).

5. **Transport replicates because it is a Pawn.** `Transport extends Pawn` with continuous

`TransportOwnerState` (world transform + linear + angular velocity) streamed to all proxies

(`3_game/vehicles/transport.c:13-30,52-53`; `3_game/entities/pawn.c:20-24`). `ItemBase` is not a

Pawn: clients get only occasional entity snapshots — never velocities. A free dynamic body on an

ItemBase looks "synced" only at low latency/local tests.

6. **The native throw path runs on server AND owner client.** `HandActionThrow` guards with

`GetInstanceType() != INSTANCETYPE_REMOTE` before `item.ThrowPhysically(player, force)`

(`3_game/systems/inventory/hand_actions.c:77-81`). That is why thrown items collide for the

thrower. Whether REMOTE clients get a local body is not visible in scripts — treat third-party

collision as unverified until tested in-game.

7. **Drop/throw physics is temporary by design.** It is governed by a lifetime:

`StopItemDynamicPhysics()` kills it via `SetDynamicPhysicsLifeTime(0.01)`

(`4_world/entities/itembase.c:4530-4534`). A long-rolling object must renew/extend the lifetime or

avoid depending on the drop path. Measured (BenchRE 2026-08-26): the default lifetime is exactly

**15 s** (n=2, `dBodyIsDynamic` polled at 4 Hz flips at t=15.00); `SetDynamicPhysicsLifeTime(3600)`

is honored (still dynamic past a 300 s watchdog).

8. **A player's EOnContact only reacts to Transport.** `DayZPlayerImplement.EOnContact` casts

`Transport.Cast(other)` and ignores everything else (hasta 1.29: `4_world/entities/dayzplayerimplement.c:3814-3829`;

1.29 real `EOnContact` is `stable-1.29/scripts/scripts/4_World/Entities/DayZPlayerImplement.c:3822-3836`;

desde 1.30 Exp: `exp/scripts/scripts/4_World/Entities/DayZPlayerImplement.c:3958-3973`).

A custom ItemBase that should hurt players must detect the contact itself and call

`target.ProcessDirectDamage(...)` from its own `EOnContact`.

9. **Script impulses push corpses, not living players.** Vanilla applies `dBodyApplyImpulse` to the

victim only when `IsDamageDestroyed()` (ragdoll) — `3_game/entities/entityai.c:4111-4115`. Living

players are displaced by the contact solver itself (both bodies present + interacting layers), not

by script.

10. **Config-driven animated geometry on a building is NOT a mover** (measured in game, DayZDiag 1.29.163709) [EXACT]: a standing player stays suspended while the piece descends; a moving player rides up but does not ride down — they stay up, can walk a few metres on "nothing", then fall; a parked car is clipped through by the rising piece; a running car rises a bit and drops. Any elevator or lift platform needs a script layer that carries the rider. (On the way down the client seems to keep the old collision for a while — hypothesis, not measured.)

11. **A platform that is a SEPARATE entity does carry riders** (measured in game, DayZDiag 1.29.163709, one client on localhost; SP-450) [EXACT]: a `House` whose config inherits `HouseNoDestruct` with `animPhysDetachSpeed=100`, moved with `SetPosition` every frame on the server AND on each client from the same clock (the server re-syncs the time every 0.25 s, the client extrapolates), lifted a standing player 8.9 m in 15 s (peak 0.93 m/s) without touching the player's position: within 5 cm on the server and 7.9 cm on the client, the client error being one frame of lag (correlation 0.89 with speed × frame time). The player must be linked (`PhysicsGetLinkedEntity() == platform`, `3_game/human.c:1403`); after a teleport they need one native step before they link.

- **Vehicles on that platform.** Asleep (`dBodyActive` `INACTIVE`) + `SetPosition` + `Transport.Synchronize()`: the server carries them but the client receives nothing until they wake — do not use. Awake only (`ALWAYS_ACTIVE`): a sedan rides well, but a `CarScript` helicopter with its own flight model bounces up to 24 cm and slides 31 cm. Awake with `SetVelocity` = platform velocity + 4 × position error, every frame: the sedan (with and without wheels) and the helicopter ride within 4.6 cm on the server and 11.5 cm on the client, and stop exactly when released.

- **The frame hook.** `EOnFrame` never reaches a `House` instance, even with `SetEventMask(EntityEvent.FRAME)` (measured `fe=0`); the `GetGame().GetUpdateQueue(CALL_CATEGORY_GAMEPLAY)` invoker runs every frame on server and client (`3_game/dayzgame.c:3035-3038`).

- **A script cannot walk a client-controlled player.** In 1.29 multiplayer with reconciliation, `OverrideMovementSpeed`/`OverrideMovementAngle` moved the player 0.24-0.40 m in 1.5 s when set on the client only, and 0.00 m when also set on the server by RPC: enough for the one step that links, not for walking.

## API quick map (verified signatures)

### Create / destroy (`1_core/proto/enphysics.c`)

```c

proto bool dBodyCreateStaticEx (notnull IEntity ent, PhysicsGeomDef geoms[]); // :38

proto bool dBodyCreateGhostEx (notnull IEntity ent, PhysicsGeomDef geoms[]); // :39

proto bool dBodyCreateDynamicEx(notnull IEntity ent, vector centerOfMass, float mass, PhysicsGeomDef geoms[]); // :51

proto native void dBodyDestroy(notnull IEntity ent); // :54

proto native bool dBodyIsSet(notnull IEntity ent); // :57

```

- `PhysicsGeomDef(string name, dGeom geom, string materialName, int layerMask)` + public `Frame[4]`,

`ParentNode` (`1_core/physics/physicsgeomdef.c:9-26`).

- Geoms: `dGeomCreateBox(size)` :186, `dGeomCreateSphere(radius)` :189, `dGeomCreateCapsule` :192,

`dGeomCreateCylinder` :195, `dGeomDestroy` :198.

- `dBodyCreateDynamic/Static` (no `Ex`) exist only under `#ifdef GAME_TEMPLATE`

(`2_gamelib/entities/scriptmodel.c:31,35`) — they do not compile in DayZ. The wrapper

`Physics.CreateDynamic(ent, mass, layerMask)` builds geometry from the entity's .p3d

(`1_core/physics/physics.c:189`).

- Recreate pattern: always `if (dBodyIsSet(this)) dBodyDestroy(this);` before re-creating.

### State, damping, sleep, CCD

```c

dBodySetInteractionLayer(ent, mask) // :59 (per body) dBodyGetInteractionLayer :60

dBodyActive(ent, ActiveState.X) // :64 INACTIVE | ACTIVE | ALWAYS_ACTIVE (activestate.c:9-17)

dBodyDynamic(ent, bool) // :65

dBodyEnableGravity(ent, bool) // :69 bool only — no vector

dBodySetDamping(ent, linear, angular) // :70

dBodySetSleepingTreshold(body, lin, ang) // :71

dBodyEnableCCD(body, maxMotion, castRadius) // :83 (-1 disables) anti-tunneling

dBodySetLinearFactor(body, vector) // :87 zero an axis => 2D physics

dBodyGetMass / dBodySetMass // :122-123

```

### Impulses, forces, velocities

```c

dBodyApplyImpulse(body, impulse) // :141

dBodyApplyImpulseAt(body, impulse, worldPos) // :136 off-center => natural torque/roll

dBodyApplyForce / dBodyApplyForceAt // :146 / :151

dBodyApplyTorque / dBodyApplyTorqueImpulse // :153 / :125

GetVelocity(ent) / SetVelocity(ent, v) // :104 / :111 global functions (work on Man too)

dBodyGetAngularVelocity / dBodySetAngularVelocity // :158 / :165 rad/s per axis, NOT yaw/pitch/roll

dBodyGetVelocityAt(body, worldPos) // :177

dBodySetTargetMatrix(body, matrix, timeslice) // :170 kinematic move

dBodyGetKineticEnergy(body) // :175

```

Wrapper-only extras: `Physics.ClearForces/GetTotalForce/GetTotalTorque/SetResponseIndex`

(`physics.c:106-115`); constants `Physics.STANDARD_GRAVITY(9.81)/VGravity/KMH2MS` (`physics.c:18-21`).

### Interaction layers (`3_game/global/dayzphysics.c:1-43`)

`PhxInteractionLayers` (bit order): NOCOLLISION, DEFAULT, BUILDING, CHARACTER, VEHICLE, DYNAMICITEM,

DYNAMICITEM_NOCHAR, ROADWAY, VEHICLE_NOTERRAIN, CHARACTER_NO_GRAVITY, RAGDOLL_NO_CHARACTER/FIREGEOM,

DOOR, RAGDOLL, WATERLAYER, TERRAIN, GHOST, WORLDBOUNDS, FENCE, AI, AI_NO_COLLISION, AI_COMPLEX,

TINYCAPSULE, TRIGGER, TRIGGER_NOTERRAIN, ITEM_SMALL, ITEM_LARGE, CAMERA, TEMP.

Runtime query pattern (vanilla, `3_game/vehicles/transport.c:556-557`):

```c

int layer = dBodyGetInteractionLayer(obj);

bool blocksPlayer = dGetInteractionLayer(this, PhxInteractionLayers.CHARACTER, layer);

```

Use the same query to log whether `CHARACTER × DYNAMICITEM` is active when debugging "walks through".

### Raycast / overlap families (`3_game/global/dayzphysics.c:123-230`)

Two separate worlds — pick the right one:

| Family | Sees | Use for |

|---|---|---|

| `RaycastRV` :199 / `RaycastRVProxy` :208 | RV geometries via `ObjIntersect*`: Fire(0), View(1), Geom(2), IFire(3), None(4) (:66-71) | cursor/action targeting, hit surfaces, melee aim |

| `RayCastBullet` :211, `SphereCastBullet` :213, `*OverlapBullet` :216-228 | Bullet physics world, filtered by `PhxInteractionLayers` | physical LOS, ground probes, area queries on bodies |

`CollisionFlags` (FIRSTCONTACT, NEARESTCONTACT, ONLYSTATIC, ONLYDYNAMIC, ONLYWATER, ALLOBJECTS) —

`1_core/proto/endebug.c:140-148`. Overlap callback: `CollisionOverlapCallback.OnContact(IEntity, Contact)`

(`dayzphysics.c:115-121`). Action-cursor ground fallback uses `RayCastBullet` with

`ROADWAY|TERRAIN|WATERLAYER` (up to 1.29: `actiontargets.c:329-331`; from 1.30 Exp: `exp/scripts/scripts/4_World/Classes/UserActionsComponent/ActionTargets.c:383-384`).

### Contacts

`sealed class Contact` (`1_core/physics/contact.c:9-50`): `Impulse` (:21), `Normal`, `Position`,

`PenetrationDepth`, `RelativeVelocityBefore/After`, `GetNormalImpulse()` (:47). Receive it via

`SetEventMask(EntityEvent.CONTACT)` → `override void EOnContact(IEntity other, Contact extra)`

(`1_core/proto/enentity.c:213`). Vanilla measures impact magnitude with

`extra.RelativeVelocityBefore.Length()` (`3_game/entities/inventoryitem.c:200`, threshold 0.3,

throttled 0.33 s) — not with `Impulse`. `Transport.OnContact` warns "Can be called very frequently in

one frame" (`4_world/entities/vehicles/carscript.c:1453`): buffer contacts, process once per tick

(vanilla caches and consumes in `EOnPostSimulate`).

### Native dynamic-item path (drop/throw)

```c

// 3_game/entities/inventoryitem.c

proto native void EnableCollisionsWithCharacter(bool state); // :21

proto native void ThrowPhysically(DayZPlayer player, vector force, bool collideWithCharacters = true); // :26

// 3_game/entities/object.c

proto native void CreateDynamicPhysics(int interactionLayers); // up to 1.29: :462; from 1.30 Exp: exp/scripts/scripts/3_Game/Entities/Object.c:456 (never called by vanilla script)

proto native void EnableDynamicCCD(bool state); // up to 1.29: :463; from 1.30 Exp: :457

proto native void SetDynamicPhysicsLifeTime(float lifeTime); // up to 1.29: :464; from 1.30 Exp: :458

```

Lifecycle: throw (`hand_actions.c:62-88`, server+owner) · inventory dump uses

`ThrowPhysically(null, force, false)` (`4_world/static/miscgameplayfunctions.c:1164-1220`) · admin

spawn-with-gravity uses `item.ThrowPhysically(null, "0 0 0")` server-side

(`4_world/plugins/pluginbase/plugindeveloper.c:381,504`) · re-config hook

`override void OnCreatePhysics()` (`itembase.c:1222-1227`; real overrides in tentbase.c, fireplace.c,

batterycharger.c). The `DYNAMICITEM` / `DYNAMICITEM_NOCHAR` pair maps to `collideWithCharacters`

by naming (inference — internal assignment not script-visible).

### Player CCT (`3_game/human.c`)

`PhysicsIsFalling` (up to 1.29: :1397; from 1.30 Exp: `exp/scripts/scripts/3_Game/human.c:1428`, comment `:1426-1427` "returns true if the ragdoll is moving greater than 1m/s"), `PhysicsGetFloorEntity` (up to 1.29: :1400; from 1.30 Exp: :1431), `PhysicsGetLinkedEntity` :1403,

`PhysicsGetVelocity` :1410, `PhysicsEnableGravity` :1412, `PhysicsSetSolid` :1414-1415,

`PhysicsSetRagdoll` (up to 1.29: :1418 comment at `stable-1.29/scripts/scripts/3_Game/human.c:1417-1418`; from 1.30 Exp: `:1451`, catalogued as old death-state system),

`PhysicsSetSimpleDeath` (from 1.30 Exp: `:1449`), `PhysicsIsRagdoll` (from 1.30 Exp: `:1452`; also `HumanCommandUnconscious.IsRagdoll` at `:647`),

`CheckFreeSpace` :1354, `CollisionMoveTest` :1357, `LinkToLocalSpaceOf` :1361.

### Joints

`dJointCreateHinge/Hinge2/Slider/BallSocket/Fixed/ConeTwist/6DOF/6DOFSpring(..., bool block, float breakThreshold)`

+ per-type setters (`enphysics.c:212-270`); break event `EOnJointBreak` (`1_core/proto/enentity.c:207`).

### Surfaces

`SurfaceInfo` (`3_game/surfaceinfo.c:8-51`): GetByName/GetByFile, roughness/dustness/penetrability,

IsLiquid/IsSolid, step/wheel particle ids. Detection: `CGame.GetSurface/SurfaceY/SurfaceGetType/

SurfaceUnderObject/SurfaceGetNormal` (`3_game/global/game.c:1160-1187`). Impact surface:

`DayZPhysics.GetHitSurfaceAndLiquid` (`dayzphysics.c:206`; used `inventoryitem.c:168-176`). No

friction getters — see truth #4.

## Recipes

**A. Custom dynamic sphere body (server-side baseline)**

```c

PhysicsGeomDef geoms[] = {PhysicsGeomDef("", dGeomCreateSphere(0.5), "material/default",

PhxInteractionLayers.DYNAMICITEM)};

dBodyCreateDynamicEx(this, GetCenterOfMassOffset(), 80.0, geoms);

dBodySetInteractionLayer(this, PhxInteractionLayers.DYNAMICITEM);

dBodyActive(this, ActiveState.ALWAYS_ACTIVE); // no mid-slope sleep

dBodySetDamping(this, 0.05, 0.2);

dBodyEnableCCD(this, 0.4, 0.45); // ~diameter*0.8, inner radius

```

Remember truth #1: created only server-side, players walk through it.

**B. Native path (recommended for items that must block/hit players)**

```c

// run on server AND owner client (replicate the hand_actions.c:77 guard):

item.ThrowPhysically(null, impulse, true); // true => collides with CHARACTER

item.EnableDynamicCCD(true);

item.SetDynamicPhysicsLifeTime(3600); // renew for long rolling [validate in-game]

```

Model requirements: Geometry LOD (collision), View Geometry (cursor — truth #2), FireGeometry (bullets).

**C. Contact damage to players (vehicle-parity, from the stone side)**

```c

void MyItem() { SetEventMask(EntityEvent.CONTACT); }

override void EOnContact(IEntity other, Contact extra)

{

if (!g_Game.IsServer()) return;

EntityAI target = EntityAI.Cast(other);

if (target && target.IsAlive())

{

float speed = GetVelocity(this).Length(); // m/s

if (speed > 0.5 && m_CanHit) // guard vs multi-contact per tick

{

m_CanHit = false; // reset via timer or target EEHitBy

target.ProcessDirectDamage(DT_CUSTOM, this, "", "TransportHit", "0 0 0", speed);

}

}

}

```

`damageCoef` IS the velocity: real damage = base damage of ammo `"TransportHit"` × coef

(`entityai.c:4086-4116`; desde 1.30 Exp: `RegisterTransportHit` at `exp/scripts/scripts/3_Game/Entities/EntityAI.c:4111`, Motorbike branch `:4143-4160`). The ammo lives in binary game data, not scripts. Vanilla resets its

one-hit guard in the victim's `EEHitBy` (`dayzplayerimplement.c:1551`; desde 1.30 Exp: `exp/scripts/scripts/4_World/Entities/DayZPlayerImplement.c:1567`). Corpse launch only:

`impulse = 40 * velocity; impulse[1] = 60; dBodyApplyImpulse(victim, impulse);` gated by

`IsDamageDestroyed()` (truth #9). Full pipeline: `references/dano-transporthit.md`.

**D. Push action (vanilla parity)**

`ActionPushCar` applies `dBodyApplyImpulseAt(car, impulse, car.ModelToWorld(car.GetEnginePos()))`

(`4_world/classes/useractionscomponent/actions/continuous/actionpushcar.c:52`). Off-center

application point gives natural roll. Stamina cost is one line: `EStaminaModifiers.PUSH_CAR` already

exists (`3_game/enums/estaminamodifiers.c:13`).

**E. Wake a sleeping body before impulses**

`dBodyActive(ent, ActiveState.ACTIVE); dBodyDynamic(ent, true);` then apply the impulse — impulses

on sleeping bodies are lost.

## Debugging physics

- Visual overlay works in retail builds: `Shape.CreateSphere(0x88FF0000, ShapeFlags.TRANSP|ShapeFlags.NOZBUFFER, pos, r)`

and `Shape.CreateLines(...)` with `ShapeFlags.ONCE` for per-frame draws (`1_core/proto/endebug.c:114-230`;

never keep a pointer to a ONCE shape).

- Log the layer matrix at runtime with the `dGetInteractionLayer` query pattern above.

- Count world bodies: `dGetNumDynamicBodies(world)` / `dGetDynamicBody(world, i)` (`enphysics.c:9-10`).

- Fast iteration: DayZDiag_x64 + `-filePatching` reloads scripts without PBO rebuild (no BattlEye, no

signature checks); see the dayz-mod-workflow skill §6 for the full loop.

## What does NOT exist (verified: 0 matches in scripts/)

| Plausible-sounding API | Reality |

|---|---|

| `dBodySetFriction` / `SetRestitution` / `SetBounciness` | physics material string per geometry + .bisurf only |

| per-body gravity vector (`dBodySetGravity`) | only `dBodyEnableGravity(ent, bool)` and global `dSetGravity(world, g)` (`enphysics.c:17`) |

| `dBodySetVelocity` / `dBodyGetVelocity` | global `SetVelocity/GetVelocity` (`enphysics.c:104,111`) |

| `dBodyApplyAngularImpulse` | `dBodyApplyTorqueImpulse` (`enphysics.c:125`) |

| `AddForce` (Unity-style) | `dBodyApplyForce*` |

| `SetMaxLinearVelocity` clamp | clamp manually per tick |

| `PhxRaycast*` | the physics-world casts are the `*Bullet` family in `DayZPhysics` |

| `EOnSimulate` on CarScript | car physics is 100% native; script only calls Set* controls |

| vanilla script call to `CreateDynamicPhysics` | declared but never called from script — no vanilla usage pattern |

| `Synchronize()` on EntityAI/ItemBase | Transport-only (`transport.c:108-109`) |

## Sleep/active enum

`enum ActiveState { INACTIVE, ACTIVE, ALWAYS_ACTIVE }` (`1_core/physics/activestate.c:9-17`).

`ALWAYS_ACTIVE` prevents mid-slope sleep for objects that must keep simulating.

## Offloading physics from the server (checked 2026-09-26)

Gameplay physics cannot leave the authority; only cosmetic physics can.

- **No out-of-process channel for per-tick work.** Vanilla scripts expose no native-extension call

(0 matches for `callExtension`, `LoadLibrary`, `DllImport` in the 1.29 and 1.30 Exp trees). The only

network exit is `RestApi`: asynchronous with a callback (`3_game/http/restapi.c:103,123`) or

thread-blocking `GET_now`/`POST_now` (`:106-108`, `:126-128`). Fine for slow, latency-tolerant work;

never for a physics step.

- **Owner prediction does not remove server work.** The authority consumes and replays the owner's move

(`3_game/entities/pawn.c:80-81`, `ConsumeMove` `:270-274`), and a native comparison runs as well, with

the more severe result winning (`:261-265`). A script `CompareMove` that always returns `APPROVE`

therefore cannot suppress corrections. Vanilla cars follow this under `NetworkMoveStrategy.PHYSICS`

(`4_world/entities/vehicles/carscript.c:3220-3230`).

- **Cosmetic physics can run per client at no server cost.** `ECE_LOCAL` creates a machine-local object

(`3_game/ce/centraleconomy.c:24`); vanilla gives local objects collision with

`ECE_LOCAL|ECE_CREATEPHYSICS` (`5_mission/gui/scriptconsoleitemstab.c:695`). Whether a local object

accepts a dynamic body is unverified.

- **Measure before optimizing.** `EnProfiler` profiles script only (`1_core/proto/enprofiler.c:62-63`,

`-profile`). For native cost, compare server CPU with and without the load on a capped server

(`dayz-test-ingame/references/dayz-1-30-test-ingame.md` § Measuring server load). On 1.30 Exp, 50

server-side dummy players sprinting did not show at 60 FPS and 100 did

(`dayz-mcp-verify/references/dayz-1-30-mcp-verify.md`).

## Cross-skill pointers

- `enforce-script-reference` — language rules, RPC/SyncVars, config.cpp, action system basics.

- `dayz-p3d-audit` / `dayz-model-pipeline` — building the Geometry/ViewGeo/FireGeo LODs that physics

and the cursor require.

- `dayz-mod-workflow` — implementation protocol + DayZDiag/filePatching fast loop.

- `dayz-sound-system` — impact/rolling audio driven from contact events (client-only rules).

## PhysicsSetRagdoll on a LIVE player — empirical evidence (added 2026-06-11)

Origin: LFSlidingFloor spike B, in-game test 2026-06-10 (script logs with complete telemetry). Updates previous expectation "no public usage on live players / probably does not simulate":

(desde 1.30 Exp: ragdoll is no longer a fully opaque native blob — vanilla ships `RagdollDef` in `exp/characters_bodies/DZ/characters/bodies/human.ragdoll`. The live-player empirical notes below still apply; the new data format, Workbench editor, and `PhysicsSetSimpleDeath` are in `references/dayz-1-30-ragdoll-and-fall.md`.)

- **SERVER-SIDE DOES SIMULATE**: with (1) DisableSimulation(false) before toggle (parity with death flow, dayzplayerimplement.c:726), (2) pre-wake `dBodyActive(p, ActiveState.ACTIVE)` + `dBodyDynamic(p, true)`, (3) `dBodyApplyImpulse(p, V*masa)` — dBodyGetMass returned actual player mass (87.5 kg) and impulse caught on first try (without need for SetVelocity). Body slid 77.6 m at 4-6.7 m/s following terrain (including uphills — extremely low effective friction).

- **OWNER CLIENT DOES NOT**: local avatar never ragdolls — remains standing and controllable (client-authoritative movement). Total server-owner desync. Live-ragdoll is only viable end-to-end with custom position sync (see LL-138).

- Toggle `PhysicsSetRagdoll(false)` does NOT rubber-band: entity stays exactly where body ended up (pos pre == post, verified).

- **DANGER get-up**: `StartCommand_Unconscious(0)` + `WakeUp` at 0.5 s left player server-side 40 m UNDER terrain, with void fall, real uncon and death. Vanilla anti-wake-early protection is 2 s (up to 1.29: playerbase.c:3169-3172; 1.29 real: `stable-1.29/scripts/scripts/4_World/Entities/ManBase/PlayerBase.c:3184` `m_UnconsciousTime > 2`). (from 1.30 Exp: the 2 s guard remains at `exp/scripts/scripts/4_World/Entities/ManBase/PlayerBase.c:3420` AND vanilla additionally refuses wake-up while falling: `if (false == PhysicsIsFalling(false))` before `hcu.WakeUp()` at `:3423-3431`. Custom 0.5 s wake paths that skip this still risk burying the body.)

## Script bodies on vanilla items — BenchRE empirical evidence (added 2026-08-26)

DayZDiag 1.29 server+client run, BenchRE mod build 0004. Evidence:

`C:\Users\<you>\dayz_re_scratch\bench_results\` (CSVs + raw logs); synthesis with 7

matrix questions in `C:\Users\<you>\dayz_re_scratch\physics_matrix.md` §6.

- **`Physics.CreateDynamic` / `CreateDynamicEx` / `CreateStaticEx` return falsy on

vanilla InventoryItem** (SmallStone/WoodenStick spawned with `CreateObjectEx`): 7/7 attempts

server-side. The NATIVE path on the same items works (`ThrowPhysically` +

`SetDynamicPhysicsLifeTime` + `dBodyIsDynamic` read 2402 ticks). Items already possess a native

body and the `Create*Ex` family does not adhere to them — coincides with its 0 gameplay uses in

vanilla. A viable host for script bodies must lack own physics (unvalidated yet:

custom entity style `scriptmodel.c`).

- **`DayZPhysics.GetHitSurfaceAndLiquid` does not name TERRAIN surfaces**: `RayCastBullet`

over open field returns valid hit_pos, but the path requires an Object and terrain is not

one (6/6 nameless probes). For terrain: `CGame.SurfaceGetType(x, z, out type)`

(`3_game/global/game.c:1166`) / `SurfaceGetType3D` (`game.c:1168`).

- **MP client: `CreateObjectEx` without `ECE_LOCAL` returns null** (n=2). For client test

local geometry add `ECE_LOCAL` (`3_game/ce/centraleconomy.c:24`; client pattern:

`3_game/particles/particle.c:119`).

## Rules promoted from the lessons corpus (added 2026-07-27)

Promoted from `AI/20_Knowledge/lessons-learned.md` so that they arrive via trigger instead

of relying on someone remembering to look them up. Each rule cites its source `LL-NNN`;

the full entry lives there. Do not remove the citation: the index detects promotion by it.

- **LL-014** — For rolling bodies, use very low but non-zero linear and angular damping and adjust sleeping threshold. Do not minimize contact friction: lives in `.bisurf`; if it slides without rotating, raise it, and if it vibrates or does not stop, raise damping.

## DayZ 1.30 Exp (build 1.30.164014)

What changes:

- Ragdoll is data-driven. Vanilla ships `RagdollDef` with 11 bones, capsules/sphere, `flesh.bisurf`, joints (`exp/characters_bodies/DZ/characters/bodies/human.ragdoll:1-202`). Workbench adds a ragdoll editor. [CHANGELOG] `work/changelog-1.30-exp-modding.md:47`.

- Death-state handling: (hasta 1.29: `DayZPlayerImplement` called `PhysicsSetRagdoll(true)` at `stable-1.29/scripts/scripts/4_World/Entities/DayZPlayerImplement.c:736`) (desde 1.30 Exp: the non-command death branch calls `PhysicsSetSimpleDeath(true)` at `exp/scripts/scripts/4_World/Entities/DayZPlayerImplement.c:745`). `PhysicsSetRagdoll` / `PhysicsIsRagdoll` remain (`exp/scripts/scripts/3_Game/human.c:1451-1452`).

- Unconscious ragdoll unhooks vehicle re-attach: `if (hcu && hcu.IsRagdoll()) m_TransportCache = null` (`exp/scripts/scripts/4_World/Entities/ManBase/PlayerBase.c:3346-3350`).

- Fall damage is exponential `CurveExp` with much lower height gates (health from **2 m**, shock from **0 m**, broken legs from **3 m**). `Randomize` no longer rolls a lethal 1.0 coef back down. Detail in `references/dano-transporthit.md` and `references/dayz-1-30-ragdoll-and-fall.md`.

- Action cursor still uses View Geometry (`RaycastRVProxy` + `ObjIntersectView`). Liquid surfaces without an object are now targets (utility 0.01).

- [CHANGELOG] hiding physics components of static meshes no longer leaves a residual collision at the origin (`work/changelog-1.30-exp-modding.md:35`). No script counterpart.

What breaks:

- `modded DayZPlayerImplementFallDamage` that copies 1.29 `Math.InverseLerp` thresholds: 2.5–4 m falls now cause shock and can break legs.

- Custom uncon wake that calls `hcu.WakeUp()` while `PhysicsIsFalling(false)` is true: vanilla now refuses; skipping the guard can still bury the body (1.29 empirical).

- Assuming player ragdoll collision/mass is 100% native and uneditable: you can now author `.ragdoll` (bind path is a `dayz-characters` concern).

Migration checklist:

- [ ] If you override fall damage: port `CurveExp` + 1.30 height constants; keep `if (pValue == 1) return pValue;` in `Randomize`.

- [ ] Custom humanoids: ship a `.ragdoll` next to the body; do not assume `LoadRagdollFile` exists in script ([UNVERIFIED] — no such call in extracted scripts).

- [ ] Custom uncon wake: keep `m_UnconsciousTime > 2` AND `PhysicsIsFalling(false) == false`.

- [ ] Action targeting over water: expect a surface target even with no object (`ActionTarget.GetSurfaceLiquidType`).

- [ ] Death path: `PhysicsSetSimpleDeath(true)` is the script-visible non-ragdoll death branch.

Detail: `references/dayz-1-30-ragdoll-and-fall.md`. Action-cursor line drift also patched in `references/fisica-engine-deep-dive.md`.