3D shapes, or three-dimensional shapes, are objects that have length, width, and height. Unlike 2D shapes, which only have length and width, 3D shapes can be viewed from different angles. Common examples of 3D shapes include cubes, spheres, and cylinders. These shapes occupy space and can be found in everyday objects, such as a basketball (sphere) or a box (cube). 3D shapes can be classified into two main categories: polyhedra and non-polyhedra. Polyhedra are shapes with flat surfaces, like pyramids and prisms, while non-polyhedra include curved surfaces, like cones and spheres. Understanding 3D shapes is important in fields like art, architecture, and engineering, as they help in visualizing and creating objects in the real world.