HowToTestModelsIngame

you have to convert the model to the ogre .mesh format, there are exporters for all major modelling programs, including blender,3dsmax,maya,wings3d,... see the http://ogre3d.org for details (TODO : link to ogre wiki page about exporters. link to ogre addons page where the exporters are.)

place the .mesh in the game dir under data/model/

you can just replace either replace existing .mesh files if you want to try things out, or you can add new object types types to the lua file

 data/plugins/common.objecttypes.lua

e.g for adding a type of furniture don't need to be a programmer, just dublicate a line like this :

 RegisterObjectType("furniture/generator", "furniture", {name="generator", gfx_mesh="sd_generator.mesh" })

and replace both "generator" occurrences with whatever your model is called, and replace sd_generator.mesh by the filename.

you can then place the furniture type inside the spaceship by selecting it form the rightclick menu.

you will probably have to rescale and rotate it.