Moin,
since youīre an 3d artist I assume you have a 3d graphics program that is able to open/save *.obj file formats and a graphics program to open/save *.tga files.
Additionally you need
There are several versions of Pack3D on the net, 5 at all. You need all of them because each version has itīs own small deficiencies/advantages.
Modelling the whole subīs interior sounds good. But as there is no trigger for additional compartements (afak) youīll have to create the interior as open room to ensure the possibility to move trough the hatches. I donīt know wether the only limitation for the cameraīs movement is the interiorīs 3d model. So, possibly you might have to hex-edit the limits.
Regards,
DD