Virtual reconstruction of an illusory space. The relief-perspective by Giovanni Maria da Bitonto in Bologna The research describes the principles of projective-geometric design of illusory spaces and proposes a methodology for the graphical study of a relief-perspective: the tabernacle designed in Bologna by Giovanni Maria da Bitonto, a fellow of Francesco Borromini in the perspectival gallery for the Spada palace in Rome. The research proposes the virtual restitution of the two spaces embodied in the projective transformation of the solid perspective: the affine space, isotropic, and the contracted and anisotropic one. The perspective of the tabernacle is used as a projective system accelerating the effects of the natural perspective to modify certain environmental aspects, external and internal to the built volumes. The research presents an unpublished graphic study on the perspective concept (a watercolor sketch found at the National Archive of Bologna) and an accurate reconstruction of the built perspective, testing the most advanced techniques of digital documentation.