Import plugin not working, despite copying example from docs

[martinbean]

Godot Version

4.1.3

Question

I’m going crazy here. I’m trying to create a basic importer plugin. My _import method, I’ve literally just copy-and-pasted an example from the Godot docs to create a MeshInstance3D and try and save it to disk, but even that doesn’t work. I just get the following error:

Can’t save empty resource to path ‘res://.godot/imported/RING1.TMD-018865a4c2cb32f2b980cb8ca348885a.mesh’.

My _import method:

func _import(source_file: String, save_path: String, options: Dictionary, platform_variants: Array[String], gen_files: Array[String]) -> Error:
	var file = FileAccess.open(source_file, FileAccess.READ)
	if file == null:
		return FileAccess.get_open_error()

	# TODO: Parse actual file

	var vertices = PackedVector3Array()
	vertices.push_back(Vector3(0, 1, 0))
	vertices.push_back(Vector3(1, 0, 0))
	vertices.push_back(Vector3(0, 0, 1))

	var arr_mesh = ArrayMesh.new()
	var arrays = []
	arrays.resize(Mesh.ARRAY_MAX)
	arrays[Mesh.ARRAY_VERTEX] = vertices

	arr_mesh.add_surface_from_arrays(Mesh.PRIMITIVE_TRIANGLES, arrays)

	var mesh_instance = MeshInstance3D.new()
	mesh_instance.mesh = arr_mesh

	return ResourceSaver.save(mesh_instance, "%s.%s" % [save_path, _get_save_extension()])

Can any one see where I might be going wrong? Why is going saying the resource is “empty” when I’m creating a MeshInstance3D, and setting its mesh property to an ArrayMesh instance that has three vertices?

[martinbean]

Fixed by saving ArrayMesh instance (a resource) instead of MeshInstance3D (node).