When you save an IGES file, a log file of the conversion is created:
Sub-sections about warnings and errors help you identify any kind of problem you might have had while converting a think3 file.
Here is an example of a log file:
Validating file ... REPORT EKGK Information ----------- ekgk_hdr - Header - 5 ekgk_error - Error Information Structure - 31 ekgk_line2d - Line 2d - 16 ekgk_nurb_curve2d - Nurbs Curve 2d - 4 ekgk_arc3d - Arc 3d - 1 ekgk_line3d - Line 3d - 8 ekgk_nurb_curve3d - Nurbs Curve 3d - 14 ekgk_comp_edge_curve - Composite Edge Curve - 5 ekgk_edge_curve - Edge Curve - 5 ekgk_rev_surf - Revolution Surface - 2 ekgk_nurb_surf - Nurbs Surface - 2 ekgk_tab_cyl - Tabulated Cylinder - 1 ekgk_trimmed_surf - Trimmed Surface - 5 ekgk_comp_curve - Composite Curve - 10 Warning ----------- Error ----------- REPORT GDX Information ----------- gdx_curve_bounded_surf - Curve Bounded Surface - 5 Warning ----------- Error ----------- REPORT IGES Information ----------- iges_100_0 - Circular Arc - 1 iges_102_0 - Composite Curve - 5 iges_110_0 - Line - 26 iges_120_0 - Surface of Revolution - 2 iges_122_0 - Tabulated Cylinder - 1 iges_124_0 - Transformation Matrix - 1 iges_126_0 - Rational B-Spline Curve (General) - 18 iges_128_0 - Rational B-Spline Surface (General) - 2 iges_141_0 - Boundary Entity - 5 iges_143_0 - Bounded Surface - 5 iges_322_1 - Attribute Table Definition - 5 iges_start - Start Section - 1 iges_global - Global Section - 1 Warning ----------- Error -----------