Hi,
LabVIEW does not recognize c3d format as such but LabVIEW is very well able to read binary or ascii files. So I guess you will have to write the VI using File I/O functions yourself. As I was Googling for c3d, i came across the following link that might come in handy to you.
http://www.c3d.org/manual/readingac3dfile.htm
Ankita