Many models have their own sliders/facial to control some materials settings, for example in order to change some colors, to increase or decrease the reflections on some parts, and so on. Some months ago when I was still working on my previous C6V2 base, I've read some articles and tutorials, mostly written by Trackdancer, DisastrousBunny and vasilnatalie or found on, all about the various settings involving the model's materials, and accessible from the Materials Tab in PMXEditor. Usable for both raytracers and for common uses with other classic shaders