Weird normal behaviour (Blender export)

Hi forum,

So, another day, another weird problem... I've started importing 3D models from Blender to Unity. I had a flipped normals problem, that I corrected by enabling backface culling in Blender then recalculating normals : that's the usual answer found on miscellaneous forum for that type of problem. So far so good.

But now the objects that had this problem still have a weird, and as far as I know undocumented behaviour : they display correctly only when seen from below a certain angle. Here is an illustration : the shoes are the objects with the problem. There are 2 screenshots from Unity with the only difference being the height of the editor camera ; last image from Blender with normals showing (never mind the glitch with the socks, that's just skin showing in places where the model does not fit well).



Not the whole shoes have that problem : the soles display correctly while the leather part and tongue do not. The main difference is that the leather part (for the tongue I don't remember) is a 2 sided object created from the extrusion of a first object.

Do you have an idea of where the problem comes from ? Or even better, what solution exist ?

 

All right, so it seems to have something to do with the FBX export (FBX 7.4 binary to be specific).

Here is a comparison between FBX (right) and the native Blender file (left) being imported into Unity.



This kind of annoys me because FBX exports were convenient to select only the desired object to export.