part 15926 (eye ball)

[Travis Cobbs]

I'm guessing you're viewing it in LDView. The faceting is almost certainly due to a bug in LDView (for which I've not found a solution with acceptable performance). Simply put, LDView's smooth shading doesn't work right when there are two adjacent co-planar triangles, and those triangles lack a type 5 line between them. However, in my opinion, adding a type 5 line between them would be wrongheaded, because LDView's behavior is definitely a bug, and the extra type 5 line would serve no purpose other than to improve the visual quality in LDView, while slowing down rendering in all viewers (including LDView).