"Rigidbody component API"

• You need a pushable crate / physics prop and don't know which members the Rigidbody component actually exposes.
• ApplyForce does nothing: wrong force scale or missing collider setup.
• A prop flies off or barely budges when the player walks into it.

The Rigidbody component's public surface isn't fully enumerated in the wiki. Some members (like MassOverride) are set-only, others (like PhysicsBody) are nullable, and force units are engine-inches-based, all easy to get wrong without a verified reference.

Verified Rigidbody members:

// Core properties
rb.Gravity          // bool - enable/disable gravity
rb.MassOverride     // float (kg) - SET-ONLY override
rb.Mass             // float (kg) - READ
rb.Velocity         // Vector3 - read/write
rb.MotionEnabled    // bool

// Physics body - typed PhysicsBody? but populated on the creation tick (26.08.05)
rb.PhysicsBody      // → .MassCenter, .AutoSleep (SET-ONLY)
rb.Sleeping         // setter per-body, GETTER reads scene-wide (see below)
rb.SleepThreshold   // float

Force API:

rb.ApplyForce(force);               // whole-step force
rb.ApplyForceAt(position, force);   // force at world point
rb.ApplyImpulseAt(position, impulse);

Dynamic prop recipe:

A pushable physics prop = ModelRenderer + non-static BoxCollider + Rigidbody:

var go = new GameObject();
var renderer = go.Components.Create<ModelRenderer>();
renderer.Model = Model.Load("models/dev/box.vmdl");

var col = go.Components.Create<BoxCollider>();
col.Static = false;  // MUST be non-static

var rb = go.Components.Create<Rigidbody>();
rb.Gravity = true;
rb.MassOverride = 10f; // kg

Push-on-contact spring (drag toward hold point):

var offset = holdPoint - body.MassCenter;
var force = offset * springK * body.Mass;
// Cap magnitude so heavy props resist a single puller
force = force.ClampLength(maxForce);
body.ApplyForce(force);

Force units are engine-based (kg·units/s²). To convert from SI Newtons, multiply by the meters-to-units constant (39.37). Light props (MassOverride small) fly; heavy ones barely move. That's F = ma working correctly.

AutoSleep is on PhysicsBody (set-only), and the creation-tick null trap is gone

AutoSleep is not a member on Rigidbody itself. The real path is Rigidbody.PhysicsBody.AutoSleep. Two things to know as of 26.08.05:

1. PhysicsBody is now populated on the creation tick. On builds ≤ 26.07.22 it read null on the same tick Components.Create<Rigidbody>() returned, so you had to defer the AutoSleep write by a tick. That trap is fixed on 26.08.05: PhysicsBody reads non-null immediately (confirmed in edit mode and in a live editor play session, across two fresh scenes; true even for a bare Rigidbody with no collider). You can set it right away.
2. AutoSleep is set-only. Reading PhysicsBody.AutoSleep no longer compiles (CS0154). You can only assign it.

var rb = go.Components.Create<Rigidbody>();

// 26.08.05: rb.PhysicsBody is already non-null here.
rb.PhysicsBody.AutoSleep = false;   // OK - set-only, don't try to read it back

Evidence is an in-editor play session (EditorScene.Play), not a shipped/networked game session. Behavior in a fully networked build may differ.

Perf corollary: s&box rigidbodies auto-sleep by default. A worst-case count of free/dynamic bodies must be split into sleeping vs. awake. A scene full of settled dynamic props is far cheaper than a naive "N rigidbodies" count assumes, and a perf budget written against the naive count overstates the cost.

Rigidbody.Sleeping: the setter is per-body, the getter reads scene-wide

Rigidbody.Sleeping's setter lands per-body: waking one crate wakes that one crate. But its getter reads scene-wide, not per-instance. Waking a single crate out of 12 scattered, non-touching crates made a census that read Rigidbody.Sleeping on every crate report all 12 as awake for 1–2 seconds, then all 12 asleep together, reproduced twice from clean boots.

A sleep census that needs genuine per-instance truth cannot call the component getter naively. Read a different per-body signal (velocity, or PhysicsBody state directly) if you must distinguish individual sleep state rather than a scene-wide aggregate.

The Rigidbody wraps a PhysicsBody managed by the engine's physics simulation. Setting Static = false on the collider is what makes the body dynamic (the default is static/kinematic). MassOverride as a set-only property means you can't read back what you set. Use .Mass for reads. Force applied per-step accumulates naturally with the fixed-tick simulation.