Yabup reads and to a lesser extent, writes a pile of different file formats.
    This version does all the same stuff as version 1.0. You can zoom, pan, rotate etc. by pressing mouse buttons and dragging.
    It can sort of modify models by pressing control and dragging with the mouse.

Additional features.

        Hierarchy view / interface.
        Bug fixes.

       compiles under Linux (if you're lucky and willing to fiddle with the makefile)(requires Mesa and WxWindows2.0) or
       compiles under Windows MSVC++v6 (requires WxWindows2.0)

Download Yabup  HERE(exe) or HERE(zip) or Source Code. Released under the Gnu GPL.

STL Example Files 1, 2, 3. There are loads of 3DS and LWO files around on the web which are a whole lot cooler