And the light is on!

Lights are the final tool in the palette of the 3D artist; they ultimately determine how real a scene appears. Realism is an abstract concept that is not always easy to grasp, so many people use default lighting or spend less time on lights than modeling and texturing. But lighting is as important as the other two, and sometimes even more important. As you may notice, this is a quite long article but it (like my previous articles) includes a large number of examples to help you understand.

The only side effect is that it may take a while to load :-/

First I will describe the different light sources we can create and what does they do.

I will use a test scene to help me in the task. Of course, only one of the top 3 lights will be active at one time, but the bottom (in the picture) infinite light will always be active to add a little bit more illumination. In my examples, I used a light blue shiny surface so you can see the light hitting the surface.

Point Light: the point light generates a light coming from ONE point and going in EVERY direction. This light can simulate a indoor light coming from a light bulb. See the example and you will notice that the light come from the top of the middle sphere.

Spot Light: the spot light generates light coming from ONE point in ONE direction. The light spreads out a certain (angular) amount; this can be varied. Spot lights are generally circular. This can simulate any spot like light, such as a maglight. In the picture below, you will notice that the middle sphere receive the light but the two on the sides are only partly illuminated.

Infinite Light: this one generates light coming from a INFINITE distance away, in ONE direction. Unlike a point light, it covers an entire scene. It allows global illumination and also outdoor lights (like the sun). In this example you will notice that all the 3 sphere have the same illumination.

Those 3 are the most important types of light and they may be found in most 3D software. Certain software has more specific lights like "projectors" that send a picture or animation like a movie projector, or area lights that simulate a surface that generates a light like a neon sign. But I will only discuss the 3 main light which most programs have.

Each light has more properties than just its type. First you may choose the color and the intensity of the light. You may for example simulate a sunny day by using a yellowish light source, or a rainy day by changing the color to a white/bluish color, or even a sunset with pink / orange colored lights. So the light color can change the "ambiance" of your final scene. The intensity parameter controls how much light will be produced by the source. Sometimes it's better to have more lights at a low intensity to archive a global illumination, as in a lighted room, and sometime a few intense spot can achieve a high contrast image. In the follow examples I changed the intensity of the light in the 1st row and the change the color of the light in the 2nd row. As you can see it changes the result a lot. I only used one infinite light to simplify the scene, so it is surely not the best result that can be achieved :-)