Positioning the Back Light
We will position a back light at the rear of the car in order to compensate for the lack of illumination there. Again we will use an Area light with no shadows or Specular highlights. Position this light as shown at the top of the image below. The bottom half of the image shows the effect this light has on the rendered object.
Multiple shadows, as generated by numerous spotlights in a stadium for example, are generally not desired in most scenes with natural lighting. Also, specular highlights generated by different light sources can also be irritating and cause the scene to look unrealistic.
Something that should be avoided when adding light sources is overexposing parts or all of the scene or brightening shadowed areas too much. In the example above, this can be observed directly beneath the car. The ground beneath the car is too bright. In reality a darker shadow should appear here because less light would penetrate the area directly between the ground and the car body.