By chocofur on youtube.com
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In this step you'll learn about normal and roughness, and specular and base color. Normal is correlated to roughness, meaning that the bumps, cracks, and scratches on a surface will affect the roughness value. Specular is correlated to base color, and darker areas will have less reflections than brighter areas. By using a bump vector node, diffuse color, and a color ramp node, you can create realistic materials in blender.