You can define ply angles for a stack relative to the first ply.
To define ply angles relative to the first ply:
In the Shell Definition PropertyManager, under Composite Options, select Ply angles relative to ply 1.
The first ply angle is always absolute.
The image shows an example of a curved panel with a hole. The first ply is oriented at 45°, shown by the white arrow, to the 0° reference. The second ply is oriented at 45° relative to the first ply or at 90° to the 0° reference. The Angle cell turns yellow when the ply angle is defined relative to the first ply. The tool tip of the angle slider 
lists both the absolute ply angle and the relative ply angle of that ply.
| First ply (45°) |
Second ply (45° relative to first ply) |
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