Smooth Shading Error

I have been modeling this Coat on my male template all day and can’t get it to render with smooth shading on without these horrible black shading creases on all sorts of poly faces. I’ve tried removing doubles and I’ve tried to flip normals I’m completely at a loss and Cannot figure out how to fix it. Any help would be great, especially advice on how to avoid these problems in the future. Thanks guys!


COAT_DESIGN.blend (510 KB)

I guess you could select the faces that are giving the bad normals and flip them.

Recalculate normals outside (ctrl+n for selected vertices) doesn’t fail for no reason. In your case, you have edges that aren’t connected to exactly 2 faces, making the mesh as non-manifold.
Mesh being non-manifold is not necessarily a bad thing but where the recalculation fails though are edges that are connected to 3 or more faces. Or in other words, there are interior faces. There’s no way to determine the correct direction for normals and since smooth shading is directly tied to normals, you get black lines.
If you go to edit mode, vertex select mode, select none and then select non-manifold (ctrl+alt+shift+m, or select menu -> non-manifold) Blender selects the edges that it thinks are problematic. It will select the open areas (edges connected to just 1 face) and edges that are connected to more than 2 faces

This is maybe the solution for you! I’ve got the same problem. Using Edge Split

Old thread, and edge split modifier is not the solution to the original problem nor a solution to avoid such problems in the future.

JA12! You are right! Edge split is useless. I read your post. Your instruction help me. Thanks!