3D Physics (Jolt/Native)

Expert guidance for high-performance 3D physics and ragdolls.

NEVER Do

• NEVER move PhysicsBody3D nodes in _process() — Use _physics_process(). Moving bodies outside the physics step causes visual jitter and unreliable collision detection [12, 13].
• NEVER scale collision shapes directly — Scaling physics shapes causes instability, inaccurate normals, and jitter. Use the shape properties (height, radius, size) instead.
• NEVER modify RigidBody3D transforms directly — This ignores the physics solver. Use apply_impulse(), apply_torque(), or the _integrate_forces() callback for safe manipulation [17].
• NEVER use RigidBody3D for platformer player controllers — RigidBody is for objects driven by physics. For refined movement, use CharacterBody3D with move_and_slide() [move_and_slide].
• NEVER leave Continuous CD (CCD) enabled for static meshes — It adds heavy CPU cost. Reserve it for high-speed small objects (bullets) to prevent them from passing through walls.
• NEVER use PhysicsServer3D RIDs without manual cleanup — RIDs are not garbage collected. If you create bodies via the server, you MUST call free_rid() when done to avoid memory leaks.
• NEVER use RayCast3D for precise ground detection on stairs — A single ray is too thin. Use ShapeCast3D with a cylinder or sphere shape to detect walkable steps reliably [Stair Logic].
• NEVER rely on VehicleBody3D for non-racing arcade vehicles — It's a complex sim. For arcade hovercraft or simple cars, a custom CharacterBody3D with Raycasts is often easier to tune.
• NEVER forget to set collision_layer and collision_mask properly — If everything is on layer 1, performance will tank from redundant checks. Categorize your world.
• NEVER use Area3D for high-frequency blocking — Areas are for detection. For walls/barriers, use StaticBody3D to ensure immediate, robust containment.