All 3D Points, Shapes, Lines, Curves, Bent Tubes, Silhouettes, Edges, Cylinders, Surfaces, Point Clouds, Meshes and Surface Drawing have a Material and a Layer. The Material is used to assign color and texture for export and 3D Viewer display and the Layer name for grouping the objects logically.
See Default Project Materials and Layers for information on how to automatically add a set of materials and layers to a project.