### 2.1.8. Oriented Selection Sets (OSS)

An Oriented Selection Set is an Element Set with additional information about the element orientations. The orientation direction of an Element Set is responsible for setting the stacking direction of the associated lay-up. The Reference Direction is responsible for setting the 0° direction of the associated lay-up. These two directions must be defined while other parameters like Selection Rules and Draping are optional.

Figure : Definition

An Oriented Selection Set is defined by:

- Name: Name of the OSS.

- Element Sets: Underlying elements for the OSS definition

- Orientation Point: Offset direction is defined at this point. The point should be inside and close to the reference surface, otherwise the mapping of the offset direction can result in wrong results.

- Orientation Directions: Vector defining the offset (normal) direction at the Orientation Point.

- Reference Direction: Defines the 0° direction of the OSS.

  - Selection Method: Defines the mapping algorithm for the Rosettes if more than one Rosette is used. For more information, see Reference Direction.

  - Rosettes: One or more Rosettes defining the Reference Direction for each element through the selected method.

  - Reference Direction Field: Defines the direction column of a 3-D Look-up Table. Only applicable to the tabular values method.

Use the Flip button to reverse the offset direction.

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