Every project has its problems and everybody has to run into an issue. As usual, my number one challenge was finishing my project in time with it at the level I believe is publishable. I have to say I am extremely proud of what I accomplished. My car paint was one of my biggest challenges and feats. I have 15 (I repeat 15) nodes that created my car paint. Four glossy, three mix, RGBs, hues, fresnel, and more. I tried to make it as convincing as possible and that is what took up the most of my time other than the basic modeling.
