Possible alpha transparency sorting issue?

[Spacebuns]

So I opened a model in the Matrix Eater and saw this in the perspective view:

Is this an alpha opacity sorting issue because I've looked otherwise and saw that the grey part is not missing faces.

 

[NhazUl]

No, they are inverted normals. So you have a one-sided material and these few faces are "upside-down". It's a common issie when copying and flipping a mesh for symmetry. Open the model in MdlVis, select the faces and click Invert Normals (or something like that, the icon is a -1).