Surface Mapping

For a composite shell, by default, the surface mapping technique determines the 0° reference shown by the red arrow. The surface mapping option is based on the UV coordinates.

The figure shows the UV coordinates and the 0° reference for a cylindrical panel with a hole. The pink curves of the left image represent the U direction whereas the transverse curves represent the V direction. The U direction controls the 0° reference angle on a composite shell. The red arrow points to the U coordinate direction.

You can rotate the 0° reference to align with the V direction. In the Shell Definition PropertyManager, under Composite Options, select Rotate 0°Reference.
UV coordinates (shown for illustration only, not visible in the interface) 0° reference