A method for manufacturing a transparent aligner for dental alignment is disclosed. The method may include: determining a tooth contour model which includes a contour portion surrounding a surface of a tooth requiring rotational correction determining an axis of rotation for the tooth requiring rotational correction determining two points touching exterior surfaces of the tooth requiring rotational correction based on the axis of rotation and a direction of rotation required for correcting the tooth requiring rotational correction, the two points being symmetrical with respect to the axis of rotation determining a rotational correction model for the rotational correction by protruding the contour portion towards a tooth surface and towards a direction of rotation at the two points and generating the 3D dental alignment model data by applying the rotational correction model.
