Node that instances a [MultiMesh]. [MultiMeshInstance] is a specialized node to instance [GeometryInstance]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). $DOCS_URL/tutorials/performance/vertex_animation/animating_thousands_of_fish.md $DOCS_URL/tutorials/3d/using_multi_mesh_instance.md $DOCS_URL/tutorials/performance/using_multimesh.md The [MultiMesh] resource that will be used and shared among all instances of the [MultiMeshInstance].