Represents the boundary positions of a shape on the surface computed from by a Surface Shapes method.

PolylineType	Gets the Polyline Type of Positions.
Positions	Gets the positions of the computed shape. Three array elements (in the order x, y, z) constitute one position.
PositionsWindingOrder	Gets the winding order of Positions.

Triangle Mesh Primitive Overview - Surface Shapes  | IAgStkGraphicsSurfaceShapesInitializer