MeshInstance in Godot 4: it is MeshInstance3D now
By Eduardo Orellana · Updated
MeshInstance is called MeshInstance3D in Godot 4. In a Godot 4 project, MeshInstance.new() fails to parse with Identifier "MeshInstance" not declared in the current scope. Did you mean to use "MeshInstance3D"?.
AppImage, x86_64. Ubuntu 22.04, Debian 12, Fedora 39 or newer.
Intel or AMD Chromebook, with Linux turned on.
What Godot is checking
GDScript resolves every name when the script loads. MeshInstance is not a class in Godot 4, so the analyzer stops before anything runs, and because the name is in Godot's own table of Godot 3 renames, the message names the replacement.
The converter carries MeshInstance to MeshInstance3D. It still draws the Mesh in its mesh property; per-surface materials are set with set_surface_override_material(), Godot 3's set_surface_material().
Reproduce it
A Godot 3 script that creates a MeshInstance in code, in a Godot 4 project.
extends Node
func _ready():
var mesh_instance = MeshInstance.new()
print(mesh_instance)
What Godot 4.7.2 prints
Godot Engine v4.7.2.stable.mono.official.ed1daf0bf - https://godotengine.org
SCRIPT ERROR: Parse Error: Identifier "MeshInstance" not declared in the current scope. Did you mean to use "MeshInstance3D"?
at: GDScript::reload (res://answers/meshinstance-in-godot-4/repro.gd:4)
ERROR: Failed to load script "res://answers/meshinstance-in-godot-4/repro.gd" with error "Parse error".
at: load (modules/gdscript/gdscript_resource_format.cpp:46)Fix it
A MeshInstance3D drawing a BoxMesh with a material override.
extends Node3D
func _ready() -> void:
var mesh_instance := MeshInstance3D.new()
mesh_instance.mesh = BoxMesh.new()
mesh_instance.set_surface_override_material(0, StandardMaterial3D.new())
add_child(mesh_instance)
print(mesh_instance.mesh.get_class(), ", surfaces: ", mesh_instance.get_surface_override_material_count())
What the fixed script prints
Godot Engine v4.7.2.stable.mono.official.ed1daf0bf - https://godotengine.org
BoxMesh, surfaces: 1Verified 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: [gdscript_analyzer.cpp line 4687, the message with its hint](https://github.com/godotengine/godot/blob/4.7.2-stable/modules/gdscript/gdscript_analyzer.cpp#L4687), [renames_map_3_to_4.cpp line 1542, MeshInstance to MeshInstance3D](https://github.com/godotengine/godot/blob/4.7.2-stable/editor/project_upgrade/renames_map_3_to_4.cpp#L1542), [MeshInstance3D class reference](https://github.com/godotengine/godot/blob/4.7.2-stable/doc/classes/MeshInstance3D.xml).
Questions
- What happened to CubeMesh?
- It is BoxMesh in Godot 4.
- What happened to SpatialMaterial?
- It is StandardMaterial3D, with the same albedo, metallic and roughness settings.