3DCoat is rendering of objects with some of material’s properties being taken into account.
Metals and non-metals (insulators) reflect and scatter light differently. Albedo, energy conservation, fresnel effect, and complex structure of relief also gives its influence into visual appearance of the surface.
Insulators are materials that have a pronounced diffuse scattering and weakly expressed specular (plastic, fabric , wood, concrete, paint and so on). Due to the diffuse scattering , we can see that the red plastic is red. And due to the reflection we can see glares on the surface.
Metals (steel, iron, gold, copper, brass, silver, etc) are materials without diffuse scattering (diffusion is always black), but clearly marked with a colored reflection. Copper has a black diffusion and strong reflection of red color. Gold has a black diffusion and a bright yellow reflection. Silver has a black diffusion and bright white reflection.