ZBrushCentral

Invalid topology?

Hi, i am experimenting with the displacement map but encounter weird problem. I created the details in zbrush, create a displacement map and pressed GOZ to go back maya. When i render it out, nothing appear and in the output window has this error “invalid topology, object will not be tessellated”.

What is this and how do i solve it?

nvm, i solved it using mesh - cleanup in maya.

Anyway anyone knows why it create a clone of my mesh when i return back to maya?