Francais

This tutorial explains how setup realistic headlight. The reader must know how to use Blender, create and modify mesh, apply material, create light and use layers.
 

Intuitively, the artist put a spot inside the car's headlight to simulate its light creation. If necessary, the spot beam's angle (SpotSi) may be modified to be the closer possible as the headlight. The second headlight is creating by a link (alt-d) of the first spot. Like this, modify the light power of one automatically change the second one. In this way, A rendering take from the rear of the car works fine. Remark, in this tutorial a spot halo is use, to show the light.

A rendering take from of the car's front shows that the method explains above cannot create realistic light. Because, even if the headlights generate light, they seem off.

Blender shows a lighted object only when it reflects light. Because, the spot is inside the headlight and the camera outside, the light reflection on the headlight goes inside it, on the opposite direction of the camera.
A little test with a square wearing a transparent material, a camera and a spot shows that quickly.

The three elements must be located on the same axis, to create two renderings.
The first will show the square illuminate from the rear.
The second will show the square light from the front.

When the two images are compare, The spot's light do not appears on the first.
The square can only seen, because a world have been use and illuminate smoothly the scene.

Light from the rear	Light from the front