Here, I use FinalGathering with a system of bright cards for the lighting. For the first time, I also used a bright large cylinder that surrounds the car for added reflectivity and better lighting.
I then found that the lighting looked off and tried to understand why. It was because the car was getting lit via FG by the large cylinder but the “car shader” wasn’t receiving any “traced light” information in that area. This would be especially useful for the “speculars” in the car shader.
I then made a cylindrical light with the same dimensions as the FG cylinder (In area light, chose “geometry”). Now the paint looks more like it’s lit by the cylinder and doesn’t just reflect it.
The effect in the beginning is a “diffuse glow” added in the Softimage Compositor.