clone method
Implementation
@override
Mesh clone([bool? recursive = true]) {
final materials = <Material>[];
if (material is Material) {
materials.add((material as Material).clone());
} else if (material is Iterable) {
materials.addAll((material as Iterable).map((e) => (e as Material).clone()));
}
return Mesh(geometry!.clone(), materials).copy(this, recursive);
}