Node that instances a [MultiMesh]. [MultiMeshInstance3D] is a specialized node to instance [GeometryInstance3D]s based on a [MultiMesh] resource. This is useful to optimize the rendering of a high amount of instances of a given mesh (for example trees in a forest or grass strands). https://docs.godotengine.org/en/latest/tutorials/3d/vertex_animation/animating_thousands_of_fish.html https://docs.godotengine.org/en/latest/tutorials/3d/using_multi_mesh_instance.html https://docs.godotengine.org/en/latest/tutorials/optimization/using_multimesh.html The [MultiMesh] resource that will be used and shared among all instances of the [MultiMeshInstance3D].