Adding Realism with Lighting
By Andrea L. Ames
VRML browsers provide viewers with a useful "headlight" feature that acts like a miner's head lamp, pointing straight out in front of the viewer at all times. The headlight can either be turned off or on, and moves as the viewer moves within your worlds. In essence, the headlight provides enough light for viewers to roam within VRML worlds and view objects. However, the headlight may not be enough when you want to add realism and special lighting effects to your VRML spaces.
Therefore, VRML also provides three types of light that simulate those in the real world — directional lights, point lights, and spotlights. Each of these emits light in a different way to imitate, for example, lighting from lamps with coned shades and real-world spotlights (spotlight), light bulbs (point light), and the sun (directional light). Because VRML lighting nodes (PointLight, DirectionalLight, and SpotLight) have no geometry, when you place them within a scene, light glows from an invisible source. In most cases, you'll want to create a light-emitting shape (like a lamp, the sun, or a light bulb) to "hold" the lighting node, so the light looks like it's emitting from the shape. You can also create objects that look as if they emit light using the Material node, but I'd refrain from this for reasons I'll explain later.
Using a Point Light
Point lights simulate most types of real-world lights: bare light bulbs, wall-mounted light fixtures, ceiling lights, and so on.
