GLC Player Open Source 3D File viewer

A nice and small, open and cross-platform viewer for 3D files is GLC_player at http://www.glc-player.net. It uses the GLC_lib library and also Qt for the GUI.

It supports a few 3D formats such as STL (for rapid prototyping applications), Collada (*.dae), OBJ (old Maya before it was even called Maya) and 3DS (old 3D Studio for DOS).

It is not a modeller, but as it loads quick, you can inspect a 3D file before a program like 3ds Max has even launched.