GiD can export the geometry in IGES format (version 5.3).
If the preference 'IGES:B-Rep output style' is set (see Preferences ), then the output file is written in Boundary representation solid model style; otherwise the surfaces are written as separated trimmed surfaces, without topological information, and the volumes are ignored.
The IGES geometric entities generated are:
102 Composite curve
126 Rational B-spline curve
128 Rational B-spline surface
142 Curve on a parametric surface
144 Trimmed surface
and the topological entities are (B Rep style):
186 Manifold solid B-rep object