Create a field out of polar angle fields.

Input parameters:

1. XY → Field encoding the vector angles in the XY plane.
2. Z → Field encoding the vector angles with the Z vector.
3. Ma → Field encoding the vector magnitudes.
4. Dg → If true, the angle fields are interpreted as degrees rather than radians.
   •  True → Degrees
   • False → Radians

Output parameters:

1. Fl → Polar vector field.