If you are seeing the contour lines, meaning the surface is pulled too tight on the model, there are a few changes you can try:
1) Reduce the number of patches. In the Exact Surfaces tab, you can relax the boundaries and reduce the tension which may prevent some of the pulling on the surface in Surfaces>Edit>Relax Surfaces.
2) In Exact Surfaces open Repair Patches menu select the Fix/Unfix Vertices option.
Hold down the CTRL key and select a red point.
This will change the points from red to green.
Changing the vertices from red to green will allow the points to "float" and smooth out when the surface is applied.
3) Demote orange contours in Exact Surfaces>Contours>Promote/Constrain.
The Orange boundaries are handled differently then the black patch lines. They do not relax and rather they try and hold the shape. Holding down the CTRL key while selecting the orange boundaries will cause the boundaries to turn to black thus relaxing the contours.
4) Try saving the file out as .STP file instead of an .IGES. Sometimes the file type makes a difference on how the CAD package imports the file.