THE MATHEMATICAL THEOREM of CASTEL del MONTE -Reverse architecture as a new methodology for analysing monuments (original) (raw)
2023, THE MATHEMATICAL THEOREM of CASTEL del MONTE
Abstract
As a castle architecture, Castel del Monte has no similar references throughout the Middle Ages and across different architectural cultures. Its confirmed uniqueness has elevated it to a symbolic monument of Frederick II's political and cultural design, and, for the inestimable universal values it embodies, Castel del Monte was included in the UNESCO World Heritage List in 1996. The best synthesis was written, in a few and dense lines, by the renowned Italian art historian Giulio Carlo Argan, in the first volume of the "Storia dell’arte italiana" (History of Italian Art) published by Sansoni in 1968: “Rigorously as in a mathematical theorem, the octagon of Castel del Monte develops […]” This unique geometric bloom with a magnetic charm, based on the octagon, which has seduced generations of architects and art historians, does not yet have an explanation in geometric-compositional terms: is it a simple symmetrical juxtaposition of functional environments, or does it hide a mathematical law that connects them in a single theorem as Argan foreshadowed? Based on a detailed and advanced three-dimensional survey, with the support of sophisticated mathematical analysis tools, and our desire to follow a rigorous scientific method harmoniously combined with a series of geometric intuitions, we believe we have identified a series of novel geometric patterns that recount a completely new version of Castel del Monte. The conclusive analyses on the geometry of Castel del Monte, including the problem of the tracing method - once published - will refute, with an extensive critical comparison never tackled before, many of Schirmer's now widely accepted, shared and rooted conclusions, and consequently, also Götze's geometric scheme. Historians will have at their disposal a new interpretative tool which we hope can stimulate a different understanding of the culture of medieval architects and their technical abilities, of which we know very little due to the secretive and initiatory nature of their craft at that time, but we believe we can still manage to read through their stones. with the mathematical collaboration of Lorenzo Roi
Figures (18)
Fig.1 3D model of Castel del Monte, larderArch. The best synthesis was written, in a few and dense lines, by Giulio Carlo Argan in the first volume of "Storia dell'arte italiana" published by Sansoni in 1968: "As rigorously as in a mathematical theorem, the octagon of Castel del Monte unfolds [...]" This singular geometric inflorescence with a magnetic charm, based on the octagon, which has seduced generations of architects and art historians, does not yet have an explanation in geometric-compositional terms: is it a simple symmetrical juxtaposition of functional environments, or is there a mathematical law that connects them into a single theorem as Argan anticipated?
Fig.2 Example of digitization and restitution of decorative and sculptural details, of the porta. of Castel del Monte, reconstructed through techniques of anastylosis and digital restoration. We immediately realized the need to start from scratch, reconceiving the castle's survey in a completely new way and above all under our exclusive care, controlling the entire process, which aimed to achieve an ambitious and unprecedented goal: to fully digitize the monument with millimetric resolution and with a particular and unprecedented attention to the decorative? features.
Fig.3 Survey of Castel del Monte with RGB point clouds, section. 2020 campaign.° The new and expanded LIDAR* survey campaign, using colored point clouds (RGB), would for the first time cover and reveal the entire historical technological infrastructure of Castel del Monte, characterized by hanging cisterns, sewer pipes, drain channels, chimneys, the large underground cistern, all the bathrooms, the dressing rooms, and the entire distribution network of staircases.
Fig.4 Graphic summary of the reverse architecture process. At the heart of this research, it was necessary to conceive an innovative methodology free from subjective interpretations, capable of translating the mass of complex data, digitally acquired, into geometric forms that could accurately synthesize the architectural volumes.
rig.5 [€] 3D statistical relief model, [—] identification of the 4 elevations of the planimetric section. ‘cough this procedure, the key stages of which can be succinctly described by the above ge (Fig.4), it was possible to generate an extremely accurate three-dimensional tistical model, from a dimensional point of view, representing the geometric synthesis the castle's wall structures.
Fig.6 Planimetric layout of the lst level where the anomalous sides are highlighted. The intersection of the statistical model with a series of horizontal planes positioned at the appropriate elevation has determined the planimetric layout of the underlying figure (Fig.6). We can certainly identify this result as the best so far obtained, both in terms of the instrumentation used and the methodology applied but, despite this, we did not consider it sufficient to achieve the goal. If you observe the octagons of Castel del Monte, you will easily notice that the sides are not exactly the same and that, in some cases (indicated in red in the plan of Fig.6), they appear strongly anomalous compared to a regular octagon.
The castle's masonry, whose geometric structure we intend to decode, is today the result of a stratification of events that have affected the stones comprising it for almost eight centuries. The ravages of time and the extensive restoration operations (Fig.7) have undoubtedly contributed to altering the original wall structure, which can, in turn, deviate from the project outline due to construction errors or unforeseen technical variations decided by the protomagister® for a variety of reasons. Fig.7 Example of the evolution of the curtain wall.
Fig.8 Graphic illustration of the octagonal regression operations. Thus, a calculation algorithm was assembled and tested with the MATHEMATICA® software, using GRASSHOPPER® in the CAD Rhinoceros® environment for the exchange of data related tc the vertices of the octagonoids. This initial phase of synthesis allowed us to compare the survey data with the respective octagonal geometric regressions, discovering that the anomalies, previously highlighted and well known to scholars, seemed to derive from deliberate choices rather than random construction errors as Schirmer contends.
Fig.9 Analysis of the vertices of the octagonal courtyard with the overlaid survey on the regression. The most significant anomalies concern the central courtyard and the 8 towers. analyzing the courtyard, we observed, in line with other authors, a centripet. deformation of the entire eastern-facing side (Fig.9).
Example of a tower at the base. Each tower has a base that is wider than its elevated body, and is embellished by a perimeter moulding that frames the tower. The metric analysis shows a_ substantial regularity of the sides of the base, which is also observed in the body of the towers with the sole exception of the sides that are inserted into the masonry of the main body (Fig.10). Fig.10 Identification of the anomalous sides of the towers and their relationship with the basement.
Fig.11 The two solutions to the problem of embedding the tower into the curtain wall The figure below (Fig.11) illustrates the geometric problem that the architect of Castel del Monte had to face, aiming to radially and perpendicularly embed the octagonal towers into the 8 vertices of the main body's masonry. To preserve the geometric regularity of the basic octagonal layout, the architect coul: choose between only two solutions:
Fig.12 The circumferences circumscribing the bases and the phantom circumferences. By drawing circumferences around the bases, we discovered that the empty spaces between the towers correspond, with reasonable approximation, to the circumferences of the same bases nestled together to form a single crown of circles, the geometry of whose centres is a hexadecagon, i.e., a polygon with 16 sides (Fig.12).
Fig.13 Symmetrical compositions of tangent circles of equal size in relation to Castel del Monte. This configuration, based on tangent circles (fig.13), conceals a mathematical bond « great conceptual and compositional beauty: the size of the crown on which the centers the tangent circles "rotate" is parameterized to the number of components and _ the: dimension.
Fig.14 Construction of the ring of the centers of the 16 circles (hexadecagon) This means that, in our case, it is sufficient to choose the size of the circumference, in which the base's octagon is inscribed, to identify the size of the circle (point X) on which the 16 centers lie, and therefore the total size of the castle (Fig.14).
Fig.15 Geometric construction of the octagonal courtyard starting from the octagon of the tower base. Every regular polygon is defined by two radii: that of the circumscribed circle (which intersects the vertices of the sides) and that of the inscribed circle, called the apothem (which instead intersects the midpoint of the sides).
Fig.16 The relationship between the floor plan of Castel del Monte and Doyle's geometric model. Looking at the schemes in the figure below (Fig.16), you will notice that in addition to the alternating generation of the turrets from the outermost necklace, the first 2 inner rings appear packed between 2 circumferences. The outer one corresponds to the circumference inscribed in the octagon of the wall, while the inner one corresponds to the circumference circumscribed around the court.
Fig.17 Hypothesis of a conceptual design restored through numerical analysis.
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