Fig. 21: HDRI lighting example this is what you can get with an HDRI environment map.

Fig. 22: Direct light place it to your tasting.

Fig. 23: final render ...is this what you get?

First of all, keep in mind that all reflective materials are influenced (obviously) by what you have around in the scene, being it other models or an environment map. In our situation, we do not have anything to reflect (just a gradient map to simulate a clear sky) so the effect can be less interesting: just using a spherical environment map you can get nice results: try to experiment with different maps, and maybe try some HDRI lighting. This way i rendered the Mini Cooper in Fig. 21.
Anyway, let’s start by creating the “sky” map: in a Syandard material put a “Gradient ramp” map in the diffuse slot. Set the first color to a light and soft blue, and the other two to white. Select “Environ” and “Spherical environment” in the “Coordinates” rollout. Go back to the root of this material and drag an instance of the newly created diffuse map on the “Environment map” slot in the Environment panel (in the menu go in Rendering > Environment).
We are ready top ut some lighting in the scene: create a “Skyligh” light and put it above the model, using the environment map as the color of the Skylight (check “Use scene environment”). Set the intensity multiplier to 0,8. Create a new “Target light” light and position it similarly to Fig. 22 (but that’s really up to your tastings). Set the “Light cone” to a value high enough to cover the entire scene, and set the color of the light to be a soft yellow/orange (ie 252.240.218). Set the shadow type to “Area shadows” to get a much more realistic effect, setting the type to “Disc light” and the dimensions to an acceptable value (in my case 100x100, just do a couple of test render to get proper soft shadows).
Now create a small plane under the bonnet, big enough to receive the shadows, and assign it a “Matte/Shadow” material, leaving the various parameters to their default values. Open the “Advanced lighting” panel (menu Rendring > Advanced lighting”) and activate the “Light tracer” plugin, leaving the parameters to their default values. The discussion of the many parameters of this panel is beyond the scopes of this tutorial, anyway the default values give almost always acceptable results, then it’s up to you to tweak the various values to get the best solution in terms of quality/speed, based on your scene setup.
Launch a new render, and you should get a result similar to Fig. 23, otherwise i failed in explaining this tutorial, or you read it without enough care ;-)

Section 7: Conclusions

This finally concludes this long 2 parts tutorial, modelling and rendering a detailed Nissan R390 GT1: such a project, as i wrote in the preface, requires carefull plannings and a lot of patience. Experience plays a fundamental role in every part of the process: the modelling and rendering setup of the Mini Cooper in Fig. 21 took me about half the time i needed for the Nissan.
My hope is that this reading has been helpfull for the 3d community, and that i gave some help to speed up the learning process with a tutorial as detailed as i could without writing a whole book. I tried to highlight the most common problems i face when modeling a car: there’s always some new obstacle each time, you know that damn surface or crease which just doesn’t look right...Anyway with some time and dedication you can always get what you want. As always, i tried to be as clear as possible, but first of all i am not english so some parts might be badly translated, and i might have omissed some explanation which i thoughts were not necessary: feel free to mail me at enrico@enriconencini.com for any question or suggetion, i’ll be ore than happy to get in touch with anybody, if free time is enough ;)
That’s it, have fun and take car...