
If I had a nickel for every time I had to clean up a bloody sketchup model for pep use, I'd have a $#!Tload of nickels!
For free modeling programs, most people like
Blender (I can't for the life of me figure it out!). There's also
Mesh Lab for editing, and
TopMod3D for easy simple platonic shapes. There's also
Google Sketchup but it's usually more trouble than it's worth, although there are a few here that can do some really nice work with it.
I would recommend going with a paid program though in order to get the most out of what you're trying to accomplish. There's
Rhino 4.0 (the program that I use almost exclusively) and it has several other plugins for rendering, lighting, and animation. It's an excellent mid grade NURBS modeling program that's used mainly for jewelry and architecture, but can also be used for virtually anything provided that you have a talent with directly editing shapes.
There's also
Solidworks and
AutoCAD which are geared more towards industrial applications encompassing everything from 747s & go-karts to bicycles, buildings, and small parts.
The Autodesk suite is also very nice for modeling.
Autodesk Inventor was my favorite back in 2002 (10th grade) and it's excellent for doing vehicles and so forth. Deep Flight II was designed on it.
Autodesk Maya is Autodesk's version of NURBS and is geared more towards animation.
And the last ones which are more or less new on the scene and amazing are
Claytools and
ZBrush. Claytools comes with an arm interface for direct sculpting feedback whereas ZBrush can be used with a drawing pad like you would use in Photoshop. These are not only direct solid editing programs but printable texture editing programs as well. I have a friend at my college who used ZBrush to model a set of workable full scale animatronic steampunk wings that she could wear and printed them out in SLS. They looked exactly like bone when she got them back and worked awesomely when they were done!
You should be able to get all of these at a deep student discount at either
CreationEngine.com or
AcademicSuperstore.com, except for Claytools (
SensAble Technologies) and ZBrush (
Pixologic)