[Kevan]

If the object contains seats and other objects do you know how to use other objects(cube or cylinder) for this purpose?

Boolean unify/subtract...yes it's what I've been doing so far.

[HWP]

I've been using Blender now for about 10 years. I work in other software as well, but prefer blender for hardsurface modeling, as well as sculpting and rigging my 3D printed figures. Here's a few screenshots of a new model I'm working on - 1975 Triumph Spitfire:

   
   
   
   
   
   

Check out http://www.facebook.com/hwpslotcars for more pics of the other bodies and figures my sons and I produce.

[ConnalM]

I love Blender. I use it often for 3D printer items. There is now a CAD addon that I am sure will make the process even easier, once I get my head round it. It's still at beta stage, though.