3D views have more shadow-casting elements than 2D views, so they yield far more information about natural lighting, shading requirements, passive solar design potential, and renewable energy potential.
To turn on shadows
Use one of these methods:
Shadows On.
Visual Style
Graphic Display Options. In the Graphic Display Options dialog, under Shadows, select Cast Shadows, and click OK. To adjust the intensity of sun, indirect light, or shadows
Visual Style
Graphic Display Options.