Importing 3D Objects into FrameForge

FrameForge imports the following 3D Object Formats

VRML generally the best format for objects as most VRML objects are lower polygon.
FBX required format for importing character objects with skeletons, collada OR VRML is recommend for non-skeleton based objects
Collada (.dae files) a powerful interchange format supported by most modeling programs
SKP Sketchup Models (version 6 and below only)

You import the models by going to the OBJECTS Menu, and, at the very bottom is an Import 3D Objects menu item with the available model types below it.

The VRML Importer allows you to define hinges and sliders within the VMRL and you can read all about it here. 

The Collada and Sketchup Importers allow you to break an imported model up into the top-level groups that were defined by the modeller in the original modeling program.  When you import either of those format types AND there is more than one top level group, then you will see the follow dialog: