DoGA The free download comes with a bunch of ready-made parts that can be exported as DXF, VRML or DirectX format models. DoGA's own format is SUF (whatever that stands for), which are ASCII text files so anyone with knowledge about 3D file format conversions should be able to write a program to convert them directly to COB etc.
Exporting to DirectX format works better, sometimes the DXF output opens in trueSpace a bit, uh, wadded up looking. If it does open with geometry OK, the normals are all backwards. trueSpace 7.x natively supports DirectX, tS 6.0 requires the Caligari Conversions Pack, tS 6.5 and 6.6 require Caligari Conversions Pack 2.
Here's a shot of bridge model 77 and turret model 93 in tS6.6, exported as DirectX then converted to COB with tS7. Models also attached. I haven't done anything other than convert their formats so they may need some fiddling with, starting with the Decompose into objects button. If you don't have tS higher than version 4.0, then any non-solid parts will be a problem. IIRC it wasn't until 4.2 that it was possible to select all the edges around a hole, click the Add Face button then click the selected edges to fill it.
If nothing else, DoGA should give you some ideas on stuff to model for spaceships!

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