Attached Link: http://www.c4d.de/

Hmmm.... C4D XL 6 has various primitives which it doesn't convert to polygons until render time... (and with the freeish version in my hands I have to say I support the idea of any addons to V6). Thse include splines that can be used to create geometry (but which I haven'y played with) and cylinders which are mathematical representations of cylinders only (until render time or conversion to polys). Maybe an import filter (along the lines of the one I use from IIRC http://www.c4d.de/ , but adding support for curves (converting to C4D primities)?