The hole there should be closed, as can be seen in the preview image. It is closed in Maya, where I created the mesh (to use it as a retopologized mesh in ZBrush).
The verts are welded, the object contains only 4-sided faces… I’ve tried importing the .obj several times and those faces are always missing. Any idea what’s happening?
Thanks!
It may be that ZBrush is rendering those as backfaces. Turn on Tool>Display Properties>Double to see if they show up.
marcus - it worked! Thank you very much. I looked it up in Maya and indeed, those normals were simply flipped. I reversed them in Maya to fix the problem, since I guess in ZBrush it would require hiding all other faces to flip the faces in question - which is not easy, since ZBrush isn’t great for selecting individual faces.
Thank you! 
