3D Shape: Classify 3D Shapes and Objects 3D shapes can be classified into three groups, those that have only flat faces, those that have only curved surfaces and those that have a combination. 3D shapes with only flat faces are called polyhedral which is Greek for ‘many faces.’ Once students can identify particular geometric features of 3D shapes and objects including surfaces, faces, edges and corners/vertices shapes can be described using these terms. Determining the difference between geometr