
Look at those areas, they seem to be some sort of reflections, I tried modifying some render settings but nothing seems to work, any idea ?
What I also dont understand is how Dave unwrapped the curtains, I dont think he used Headus because he has lots of tiny triangles, he probably used Automatic mapping but again what I dont understand is how he positioned all those pieces like that.
I tried using headus to unwrap the curtains and tried to get close to his result but I cant, as soon as I try to unwrap them it creates an unbelievable mess. I tried to use a plana or either Y axis in maya and then use the new unfold 3d, it creates a huge circle. I tried to unwrap on X, same result.

This is Dave's result

No idea how he did it