How does a *.cgr format differs from other similar (step and iges) formats in Catia V5?
cgr-files only present the outer surface of a part/assembly. This surface is tessellated (consist only of triangles). This format is only for representation (DMU).
If you get an IGS, STEP file, you can´t see the history, but you can work with the surfaces or volumes (for example edge fillet or hole)
If you get an CGR, you can´t see the history and you can´t work with it.
we can work with it in some special way ,such as the measurement tool to create curves
thanx mr. hailstone :)