The complicated background comes from the use of the displacement mapping.You can use a greyscale image to push the details in and out of the original polygon.Take a look here
Hello and thank you very much for your long post about my artwork dear @hlezama https://www.google.com/search?client=firefox-b&biw=1280&bih=603&tbm=isch&sa=1&ei=6Z80XL_WGI3VkwWt6Y6IBw&q=displacement+mapping&oq=displacement+mapping&gs_l=img.3..0i19l2.3319.3319..4388...0.0..0.105.105.0j1......0....1..gws-wiz-img.-8qYoDJN_zw