R10 doesn’t support Shockwave 3D
From the Maxon website:
* Unfortunately, Shockwave 3D format is not supported in CINEMA 4D Release 10 and greater on the Macintosh platform, because the API is not yet compatible with Apple’s Universal Binary XCode development environment.
https://www.maxoncomputer.com/faq_detail.asp?idnum=2200&searchType=BASIC