Hi Mark,

> Regarding the way I have modelled it, I have a habit of
> lofting/networking halves of objects then mirroring & joining,
> perhaps not a good practice?

That should be fine...


> Model is joined as I have found that light gaps occur between
> surfaces unless they are joined prior to polygon export.

Well, from your screenshot it looked like there were some different flipped parts along the hull. When things are joined they should all get a consistent direction, so it seemed like some of those parts were possibly not joined with one another?

But yes aside from getting a consistent normal direction between joined pieces, there is also additional work done for the mesh generation along joined edges to make sure that there is a unified mesh vertex structure at those spots. If pieces get meshed completely independent from one another (not joined to one another) then it is possible for the meshes of each surface to be slightly different from one another and you can get slight cracks when 2 sets of polygons do not align with one another (see this previous post for an illustration). So yes that's another good reason to have pieces joined to each other.

- Michael