Unity Physics (Rigidbody / PhysX)

Make objects move, collide, and detect each other with Unity 6.3 LTS's built-in 3D physics (PhysX). Get the FixedUpdate discipline, trigger-vs-collision rules, and collision layers right. Targets Unity 6.3 LTS (6000.3).

Unity 6 renames: Rigidbody.velocity → linearVelocity, drag → linearDamping, angularDrag → angularDamping. The old names still compile in 6.3 LTS but are obsolete (warnings; the API Updater offers the rename), so write the new names. PhysicMaterial → PhysicsMaterial is a hard compile error in old code.

When to use

• Use when giving an object physical motion (forces, velocity, gravity), responding to collisions or triggers, setting up collision layers/masks, raycasting for ground checks or line-of-sight, or connecting bodies with joints.
• Use when scenes/prefabs contain Rigidbody + Collider components.