Are there any free modelling applications?

I know some of the ship modellers use professional modelling packages that cost lots of money to make ships for SH3, but does anyone know of any freeware programs that would enable me to view models in 3D?

I need something that will allow me to import model files to the application, (that may have been built in a different file format), and see inside the model, to view the zone and sphere co-ordinates in 3D.

The idea behind it is to be able to modify the behaviour of some of the ships, to make them more realistic ( i'm still trying to get the A/C's to behave better when under attack from gunfire).
I don't want to alter the model, just the settings for the zones and spheres, a bit of tweaking really.

I've tried misfit and blender, but can't import SH3 model files to them, and don't have days to spend learning my way round software packages just to view a model in 3D and make some relatively minor alterations.
Also, when it comes to things like flotability, critical flotation, critical chance etc, as in the zones.cfg file, how do i tell which is a stronger or weaker setting for the particular zone i'm trying to tweak?
And when an armour value is -1, where can i find out what that armour level is?

There seems to be very scant information available on what these values represent, so, like most people i have no idea how a ship model's behaviour is defined.
Obviously the zones and spheres have 3D co-ordinates, zones being boxes of various shapes defining areas like engine rooms,ammo/fuel bunkers etc, and spheres being circles dependent on their radius controlling effects such as fire and smoke.

Hence the need to see them in 3D, and understand the armour levels, flotability etc. values to assign to them in order to achieve the desired effect.
It's a shame there's not some kind of guide available to explain what these values mean, or if there is, can someone please point me to it?
Any info welcome
X = Width, Y = Height, Z = length. ( Thanks to VonDos ) for that one