How thick are you modeling the frame? The renders give the perception of proper thickness for the metal frame, but the wire frame looks like it is only a single polygon in thickness.
There are actually just a few parts that have thickness, they are highlighted in the screen below, the rest are indeed just single surfaces.
The interior will be separately modelled to make texturing a bit easier
my eyes thak you for this pleasure you gave to them
Claudio 'Naxos' gallego, CG artist and teacher... http://www.chromelight-studio.fr
"1+1=3... for large values of 1"
"Circle is the fastest way from a point to itself"