Thanks for the answer
CryHam {l Wrote}:If you have your own normalMap you can use it there, eg. normalMap roadNew_norm.jpg, if not use that one, or you can generate it from your roadNew.jpg using gimp and normal map plugin.
I will process like that and download Gimp and it's normal map plugin, but is a normal map necessary or just recommanded ?
I never got really the point of normal maps in video games, so it's a bit hard to understand why to make a normal map. Some english words are unknown for me such as "smooth" (I always understand it as the opposite of "brutal" but I'm not sure).
It look hard to make a normal map, Gimp only render me a light blue picture with not any blue/purple variation (I guess a normal map should have many of these colors variations, if not, the file is useless).
I just hope a normal map isn't necessary

I try to edit the material files now.