Network physics: shared deterministic simulation

Shares one deterministic rigid-body simulation between the server and every client, with boxes, spheres, capsules, ground, gravity, collisions, forces and impulses that run identically everywhere.

Source: module-kits:kits/net_physics/usage/en.mdView Markdown source

Also read offline — CLI: grip-forge docs net-physicsMCP tool: gripforge_docs { "topic": "net-physics" }

Network physics: shared deterministic simulation (net.physics) #

What it is for #

Shares one deterministic rigid-body simulation between the server and every client, with boxes, spheres, capsules, ground, gravity, collisions, forces and impulses that run identically everywhere.

It needs game.engine; installing it brings them in.

Turn it on #

Install the kit in a project, then change a setting (the values shown are its defaults):

gripforge_gamekit_install   { project_id: "gkp_…", id: "net.physics" }
gripforge_gamekit_configure { project_id: "gkp_…", id: "net.physics",
                              config: { "gravity": [0, -9.81, 0], "ground": true } }

First example #

This is the body of the passing test the_options_are_handed_over_as_given; the helper functions it calls are defined at the top of the same test file.

#[test]
fn the_options_are_handed_over_as_given() {
    let mut s = world(
        json!({"gravity": [0, -3.7, 0], "ground": false, "groundY": -2, "hz": 60, "iterations": 8, "worldLimit": 500}),
    );
    assert_eq!(
        config_of(&mut s).unwrap(),
        json!({"gravity": [0, -3.7, 0], "ground": false, "groundY": -2, "hz": 60, "iterations": 8, "worldLimit": 500})
    );
}

Settings and defaults #

Descriptions come from the kit manifest and stay in English.

Setting	Type	Default	Range or values	Meaning
`gravity`	array	`[0, -9.81, 0]`		Gravity (m/s², canonical space: +Y up).
`ground`	boolean	`true`		A static ground plane at groundY.
`groundY`	number	`0`	-100000–100000	Height of the ground plane (m).
`groundHalfExtent`	number	`10000`	1–100000	Half-size of the ground box (m).
`groundThickness`	number	`1`	0.01–100	Thickness of the ground box under groundY (m).
`groundFriction`	number	`0.5`	0–100	Friction coefficient of the ground.
`hz`		`0`		Fixed simulation rate (Hz).
`iterations`	integer	`4`	1–64	Solver iterations per step.
`worldLimit`	number	`100000`	1–100000	Bodies placed beyond ±worldLimit m are refused (the protocol ceiling is 100000 m: f32 keeps centimetres there).
`maxSpeed`	number	`10000`	1–10000	Bodies given a linear or angular speed beyond this (m/s, rad/s) are refused (protocol ceiling 10000).
`bodies`	array	`[]`		Initial bodies of the shared world (server side for claim / authoritative; every peer for rollback, ids from 108: the physics…

Services, events, variables #

Service net.physics: Deterministic shared rigid-body world of the network core (sync physics: shared).
Events emitted:
- net.contact (a, b, impulse) — Two bodies touched during the last step (web runtime, opt-in).
Variables:
- net.physics.bodies (number) — Shared bodies

Hooks and modding #

This kit declares no hook and no collection to mod.

Engines #

Declared targets: web, godot, unity, unreal. gripforge kit api net.physics lists the exact settings and services of your version.

Versions #

Kit version 1.1.0.