Here are two examples of drawings and images where 3D effects have been added. In the following study, I will ask you which image of several, in your opinion, has the best 3D effects. Please take a moment to study these examples before continuing. Notice how the 3D images incorporate shading, shadows, lighting and reflectance to give a feeling of depth.

Lion drawing
Original drawing
Lion rendering
Drawing + 3D effects
Rings drawing
Original drawing
Rings rendering
Drawing + 3D effects