How I Did This: BMW M2
When light painting a car, multiple exposures that light different portions of the car are needed. The number of exposures will vary depending on the desired look. Still, you usually look at five to six exposures as a minimum, including the side, front (or back), and top. It would be best to capture separate exposures of the wheels, headlights (or tail lights), and the interior. Again, this all comes down to what look you are going for.