This is a real nice try, Patrice!
Just let me remind you of one fact on the material colors and lighting interaction.
You're using the AO maps and Ka coefficient in your mat file. While these maps and parameter are in fact utilized to some extent in calculating the material's diffuse color, their contribution is next to negligible and almost unnoticeable regardless of how largely overbright Ka happens to be.
The largest contribution of the AO maps and Ka is made to the
ambient component of scene lighting. But your ambient lighting components of the three lights in the scene are
zero. I'd say for all intents and purposes, you're just wasting the AO map VRAM and TU. Consider adding some ambient lighting and reducing Ka to a reasonable value within [0.0,1.0]. Then you'll get the shadows to attenuate the bumps and recesses emulated by the model's normal maps.
The overall metallicity may thus become not so evident. Then increase the Ks and Ns coefficients to over-brighten, and possibly reduce the radii of, the model's specular highlights to make the materials look truly metallic again.
(Please excuse me for my humble attempt to give a layman's advice to such a highly professional designer as you are )And while we are at it, I suggest we also use this opportunity to add emissive/glow maps (
map_Ke) officially to our materials, TU arsenal, and shader. The time will once come when we have full-blown FBO post-processing and are able to emulate veritable emissive glow. The map_Ke option will then come in very handy. If there's no glow map for a particular non-emissive material, the corresponding TU will just use a default entirely black dummy texture.
