This paper presents a quality assessment approach to evaluate the topology and fiber orientation of complex shaped variable-axial layers in the preforming process of an airfoil as part of a structural composite jet engine guide vane. An overview about the manufacturing-process of variable-axial composite vanes is given and the concept of Digital Twins is presented. To assess the quality of manufactured prototypes an ideal approach is presented and adapted to an existing prototype manufacturing process via the concept of Digital Twins. A Digital Master model and its specifications are presented. To assess the topology of manufactured and preformed layers in the airfoil, an optical data capture tool is used. The captured data of a preform is interpreted by image analysis software and transferred to a digital model of the engine guide vane. By referencing the resulting Digital Shadow against the Digital Master, a conclusion about the manufacturing and preform process quality and its influence on structural characteristics is generated.