- United Kingdom
Are you using Blender? If yes then what is not working and what tutorial are you using?
They look like they have rubbish shader settings, probably KS ambient is set too low, but KS diffuse is set alright. What that means is that they will look okay under light, i.e. in game but not in certain previews. You can download these presets to fix the basic properties (albeit I can say from experience that they almost certainly need texture improvements), just drop them under Documents>Assetto Corsa>Editor>Materials Library
You can then apply them to different materials in the CM showroom.