displaying complicated 3d objects in QT

A promising way to display 3d models in QT may be to load in 3DStudio .3ds files.

An open source library and example for doing this:
libQGLViewer contribution examples

Google sketchup supports .3ds files, and 3DStuio max seems to have quite a market share.

VRML is another likely suspect.

This site has great models for $50 each in a myriad of formats:
http://www.amazing3d.com/services/aircraft1.html


The more Mac centric Quesa 3D library, has some cool sounding models http://prdownloads.sourceforge.net/quesa/quesaexamples-1.8.tar.gz?download

However, its models are in .3dmf format. 3dmf models aren't real Windows or OpenGL friendly. This is a promising, Mac only, 3dmf to 3ds converter:
http://www.vargr.com/imagery/imagery3d.html