If loading new models, either custom or default, into either the Doom 3 or Quake 4 editor results in the objects appearing as 'entity boxes' instead of the model itself, don't worry, it's a know 'issue' with QeRadiant (upon which both the Doom 3 and Quake 4 editors are based) and providing nothing is actually wrong with the model, simply selecting the entity object box either copy/pasting it in place (where it is) or hitting the space bar to 'duplicate' it will fix the problem.
Doing either should 'force' the rendering of the model in question.
