You can convert major 3D File formats to Google Earth 4 format (KMZ) with ‘SOLA G2’. 
Supported 3D Formats
- Autodesk *.FBX (2006.11)
- 3D Studio *.3DS
- Wavefront *.OBJ
- Autodesk *.DXF
- Collada *.DAE
Download
- for Windows – 4.64 MB (4,875,755 byte)
- for Mac – 12.7 MB (13,409,054 byte)
via
イークラフト – SOLA G2
