RigidBody in Godot 4: it is RigidBody3D now
By Eduardo Orellana · Updated
RigidBody is called RigidBody3D in Godot 4, and its mode property is gone: freeze and freeze_mode replace MODE_STATIC and MODE_KINEMATIC. In a Godot 4 project, extends RigidBody fails to parse with Could not find base class "RigidBody".
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What Godot is checking
GDScript resolves the class after extends when the script loads. RigidBody is not a class in Godot 4, so the script fails to parse and nothing in it runs.
The converter carries RigidBody to RigidBody3D. A body Godot 3 put in MODE_STATIC is a RigidBody3D with freeze = true; MODE_CHARACTER is lock_rotation = true. Godot 3's apply_impulse(position, impulse) takes the impulse first in Godot 4: apply_impulse(impulse, position).
Reproduce it
A Godot 3 script that extends RigidBody, in a Godot 4 project. The scene is one Node carrying it.
extends RigidBody
func _ready():
print("ready")
What Godot 4.7.2 prints
Godot Engine v4.7.2.stable.mono.official.ed1daf0bf - https://godotengine.org
SCRIPT ERROR: Parse Error: Could not find base class "RigidBody".
at: GDScript::reload (res://answers/rigidbody-in-godot-4/repro.gd:1)
ERROR: Failed to load script "res://answers/rigidbody-in-godot-4/repro.gd" with error "Parse error".
at: load (modules/gdscript/gdscript_resource_format.cpp:46)Fix it
A RigidBody3D frozen, then released with an impulse.
extends RigidBody3D
func _ready() -> void:
freeze = true
print(get_class(), " frozen: ", freeze, ", mode: ", freeze_mode == RigidBody3D.FREEZE_MODE_STATIC)
freeze = false
apply_central_impulse(Vector3(0, 5, 0))
print("lock rotation: ", lock_rotation)
What the fixed script prints
Godot Engine v4.7.2.stable.mono.official.ed1daf0bf - https://godotengine.org
RigidBody3D frozen: true, mode: true
lock rotation: falseVerified on Godot 4.7.2
Both scripts on this page were run headless on Godot 4.7.2 (4.7.2.stable.mono.official.ed1daf0bf) on 18 October 2026, and the output above is what Godot printed, unedited.
Where the check lives in Godot's source: [renames_map_3_to_4.cpp line 1588, RigidBody to RigidBody3D](https://github.com/godotengine/godot/blob/4.7.2-stable/editor/project_upgrade/renames_map_3_to_4.cpp#L1588), [RigidBody3D class reference](https://github.com/godotengine/godot/blob/4.7.2-stable/doc/classes/RigidBody3D.xml).
Questions
- How do I move a RigidBody3D directly?
- Freeze it with freeze_mode FREEZE_MODE_KINEMATIC and move it, or apply forces; setting position on a moving body fights the physics.
- What is the 2D version?
- RigidBody2D, which made the same change from mode to freeze.