In our testing so far, Strata Design 3D CX 6.x is working well on Snow Leopard (10.6).

  

One issue has been discovered in Design 3D CX 6.0 - an occasional crash when clicking on the Convert button.

 

The Convert button issue has been resolved in Design 3D CX 6.1. 

Also, the Strata 3D Vector plug-in for Strata Design 3D CX 6.x will not work on Snow Leopard unless you install the optional support for PowerPC backward compatibility (Rosetta).