Reconstructing a Submerged Villa Maritima: the Case of the Villa Dei Pisoni in Baiae

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Article Reconstructing a Submerged Villa Maritima: The Case of the Villa dei Pisoni in Baiae

Barbara Davidde Petriaggi 1 , Michele Stefanile 1,*, Roberto Petriaggi 1, Antonio Lagudi 2, Raﬀaele Peluso 2 and Paola Di Cuia 2

1 Istituto Centrale per il Restauro, 00153 Rome, Italy; [email protected] (B.D.P.); [email protected] (R.P.) 2 3D Research s.r.l., 87036 Quattromiglia, Italy; [email protected] (A.L.); raﬀ[email protected] (R.P.); [email protected] (P.D.C.) * Correspondence: [email protected]; Tel.: +39-3-921043813

Received: 30 September 2020; Accepted: 21 October 2020; Published: 25 October 2020

Abstract: Among the activities planned for the MUSAS Project, the digital reconstruction of the underwater sites constitutes a particular challenge, requiring strong cooperation between archaeologists and technicians. The case of the Villa dei Pisoni in Baiae, one of the richest in the Phlaegrean territory, is particularly interesting: the architectural remains, already documented in the 1980s and now inserted in one of the diving spots of the Underwater Park of Baiae, are disseminated on a huge surface, including quays, thermal complexes, a fishpond, and a large, luxurious viridarium. The effort required for the digital reconstruction of the ancient villa improved the previous knowledge and the lack of documentation even in a well-known site. In this paper, we will retrace the long path from the 3D reconstruction of the archaeological remains to the virtual architectural model of the villa, the numerous challenges, doubts, and uncertainties in the creation of the original spaces, and the support offered by the ancient sources, both literary and iconographic, in solving archaeological problems.

Keywords: underwater cultural heritage; Baiae; submerged sites; 3D reconstruction; villae maritimae

1. Introduction: The MUSAS Project The UNESCO 2001 Convention on the protection of the Underwater Cultural Heritage [1] set new priorities in maritime archaeology, strongly emphasizing the importance of the in situ heritage protection and the need for new strategies for its enhancement; innovative projects are nowadays trying to develop shared guidelines and best practices to make easier and safer the enjoyment of cultural heritage in underwater environments, enlarging the public access and including, when it is possible, also people who cannot practice scuba-diving: a vast segment of public, hitherto excluded from the enjoyment of underwater heritage, or limited to a visit to the few dedicated museums or to the still very rare itineraries in coastal sites with transparent bottom boats. The MUSAS Project (MUsei di Archeologia Subacquea, Tutela valorizzazione e messa in rete del Patrimonio Archeologico Subacqueo [Campania, Calabria, Puglia]), with a funding of 3,250,000 euros within the PON “Cultura e Sviluppo“ program, intends to promote the knowledge of the rich underwater archaeological heritage of southern Italy through new technologies, favoring the fruition of underwater sites and ﬁnds, even remotely and in a virtual way, guaranteeing at the same time a constant monitoring [2–4]. For the Istituto Centrale per il Restauro (ICR—the Institute for Restoration of the Italian Ministry of Culture and Tourism—MiBACT), it is a new challenge in the ﬁeld of marine archaeology, after the long experience of the ICR-NIAS, the Underwater Archaeological Interventions Unit established in

Heritage 2020, 3, 1199–1209; doi:10.3390/heritage3040066 www.mdpi.com/journal/heritage Heritage 2020, 3 1200

Rome in 1997 and long directed by R. Petriaggi, that headed an exciting season of works on submerged sites, in Italy and abroad, in Yemen, Oman, and Libya. The MUSAS team, led by the current NIAS director, B. Davidde, creator of the project, has been carrying out since 2017 several underwater campaigns, in addition to the implementation of a big web portal (www.progettomusas.eu) and the execution of a large 3D survey campaign, both in the selected sites and in the museums. One of the key points of MUSAS, actually, is the creation of a Virtual Museum for the Underwater Archaeology, easily accessible by PC/Mac and mobile devices, in which the huge amount of data and images acquired in field missions can be shared; the users are now able, using their personal devices, or the totems that will be installed soon in the museums, to virtually dive in the sites, exploring the submerged ruins of Baiae, the port of Egnatia, the architectural remains on the seabed of Kaulonia; they also have access to accurate 3D models and to the virtual reconstructions of spaces and environments in their original aspects; moreover, they are able to explore a virtual gallery in which they can find the 3D models of a rich selection of underwater findings from all of the partner museums: statues and altars, amphorae and anchors, freely scalable and rotatable in order to facilitate their analysis. Within the working group, the archaeologists paid particular attention to enriching the user’s experience with detailed charts and explanations of the sites and artefacts, as well as with rich archives of materials for the needs of scholars and researchers. The biologists, on the other hand, had the task of examining the colonization of ancient structures by marine organisms, in order to provide the tools for an updated assessment of the degradation and for a planning of conservation interventions. Lastly, the aspect of environmental monitoring has been considered with the deployment in the selected sites of a network of submarine sensors, functional to the verification of different parameters, but also to the location of divers; in fact, an innovative system has been deployed that will make possible, in a very short time, diving tours with the use of tablets able to perform an augmented visualization representing the actual conditions of the ancient ruins in the underwater site and an interpretative 3D reconstruction of the archaeological remains as they appeared in the past [5].

2. The Villa dei Pisoni Baiae, the luxury thermal Roman resort condemned to submersion by the Phlegraean bradyseism, is a very evocative place for the Italian underwater archaeology: it was the theatre of the first underwater explorations in a submerged structure by N. Lamboglia, just after the pioneering campaigns of Albenga, and quickly became a site of excellence for the experimentation of new excavation strategies, documentation, protection, enhancement, and mainly, in situ restoration of the underwater cultural heritage [6]. The MUSAS project is operating in two different sites within the complex of the ancient Baiae. The first one is the magnificent nymphaeum/triclinium decorated with sculptures that was part of the palace of the Emperor Claudius, and which today lies underwater not far from the tufaceous promontory of Punta dell’Epitaffio [7]. The archaeologists have been working to document and to register the state of conservation of the walls and of the sumptuous coverings, but also to better understand the architectural characteristics of the monument, which was repeatedly subject to works and rearrangements during its long history before the submersion; the detailed 3D survey of the entire site has already been completed during the first season of the project, and will soon be available on the dedicated portal together with the 3D interpretative reconstruction of its features at the time of Claudius. The second site in Baiae selected for the MUSAS Project is the gigantic Villa dei Pisoni, whose viridarium surrounded by a portico marked by niches and half-columns is today one of the favorite destinations for a large number of divers. The villa, which takes its name from the Calpurnii Pisones, who were responsible for a conspiracy against Nero and related to the owners of the magnificent Villa dei Papiri in Herculaneum, extends over a large area close to the lacus Baianus, the ancient port basin today entirely submerged but once surrounded by piers and arches, villae maritimae, and palaces [8–10]. In this case, too, the archaeological study and the realization of 3D surveys will allow offering to the Heritage 2020, 3 1201 Heritage 2020, 3 FOR PEER REVIEW 3 to the public the possibility to virtually explore a complex and stratified site, and to the archaeologists public the possibility to virtually explore a complex and stratified site, and to the archaeologists the the tools for a new understanding of the articulation of the villa and of its various construction phases. tools for a new understanding of the articulation of the villa and of its various construction phases. Underwater researches carried on during the MUSAS Project revealed new important aspects of the Underwater researches carried on during the MUSAS Project revealed new important aspects of the architectural structure of the villa: with the help of the digital reconstruction, and thanks to the direct architectural structure of the villa: with the help of the digital reconstruction, and thanks to the direct archaeological observation it has been possible to remark the different building phases of the archaeological observation it has been possible to remark the different building phases of the complex, complex, from the Late Republican Age to the second century AD and the time of the Emperor from the Late Republican Age to the second century AD and the time of the Emperor Hadrian; at the Hadrian; at the same time, it has been possible to point out the exceptional architectonic solutions same time, it has been possible to point out the exceptional architectonic solutions adopted in the adopted in the first nucleus of the villa on the ancient—now submerged—promontory in front of first nucleus of the villa on the ancient—now submerged—promontory in front of Punta Epitaffio: Punta Epitaffio: an impressive modification of the original landscape, with artificial piers and quays an impressive modification of the original landscape, with artificial piers and quays that were built that were built directly in the sea, taking advantage of the astonishing possibilities offered by the directly in the sea, taking advantage of the astonishing possibilities offered by the volcanic ash of volcanic ash of Campania, the so-called pulvis puteolanus, in the setting of pilae and concrete buildings Campania, the so-called pulvis puteolanus, in the setting of pilae and concrete buildings in submerged or in submerged or partially submerged environments [11]. partially submerged environments [11]. As a parallel activity, the 3D acquisition of a rich selection of artefacts from the Archaeological As a parallel activity, the 3D acquisition of a rich selection of artefacts from the Archaeological Museum of the Phlegraean Fields has also already been completed: more than sixty 3D models, Museum of the Phlegraean Fields has also already been completed: more than sixty 3D models, mostly mostly sculptures, discovered in the Gulf of Pozzuoli and rich in stories and connections with the sculptures, discovered in the Gulf of Pozzuoli and rich in stories and connections with the intense life intense life that was led in amoenis Baiis, between the villas of the most important figures of republican that was led in amoenis Baiis, between the villas of the most important figures of republican Rome and Rome and the sumptuous palaces of the emperors, from the Julio–Claudian dynasty onwards. the sumptuous palaces of the emperors, from the Julio–Claudian dynasty onwards.

3.3. Source-Based Source-Based 3D 3D Modeling Modeling

3.1.3.1. The The Study Study of of the the Sources Sources TheThe methodology methodology described described in in [12] [12] has has been been used used for for the the creation creation of of the the digital digital reconstruction reconstruction ofof the the Villa Villa dei dei Pisoni. Pisoni. The The very very first first step step of a of hypothetical a hypothetical 3D reconstruction 3D reconstruction process process is collecting is collecting and studyingand studying the sources. the sources. Scientific Scientific publications, publications, books, books, archaeological archaeological maps, maps, illustrations, illustrations, photos, photos, frescoes,frescoes, vascularvascular paintings, paintings, contemporary contemporary references references and every and document every concerningdocument archaeological concerning archaeologicalsurvey and excavations, survey and may excavations, be a precious may help be a in precious defining help the featuresin defining of buildingsthe features and of structures. buildings and structures.In the case of the Villa dei Pisoni, most of the material has been provided by the archaeologists. In particular,In the case ancient of the paintings, Villa dei mainlyPisoni, comingmost of fromthe material Pompeii has and been from provided the other by Vesuvian the archaeologists. sites, already Incollected particular, in several ancient general paintings, studies mainly on archaeology coming from and Pompeii iconography and from of Roman the other maritime Vesuvian villas sites, [13], alreadytogether collected with some in recent several 3D general hypothetical studies reconstructions on archaeology and and illustrations iconography of contemporary of Roman maritime villas (the villas3D reconstruction [13], together of thewith Villa some dei Papiri recent in Herculaneum3D hypothetical by Capware, reconstructions Italy [14 ],and the Villaillustrations Maritima of of contemporaryMinori, the Villa villas di Poppea (the 3D located reconstruction in Oplonti), of the were Villa at thedei basisPapiri of in various Herculaneum reconstruction by Capware, hypotheses, Italy [14],especially the Villa about Maritima the dock of Minori, and the the seafront Villa di of Poppea the villa located (Figure in1). Oplonti), were at the basis of various reconstruction hypotheses, especially about the dock and the seafront of the villa (Figure 1).

(a) (b) (c)

Figure 1. (a) A sketch made by the archaeologists making hypothesis about the villa’s appearance; Figure(b) One 1. of(a) the A sketch numerous made Pompei by the archaeologists frescoes representing making hypothesis a seafront monumentalabout the villa’s villa; appearance; (c) A Roman (b) Onelighthouse, of the fromnumerous a later Pompei illustration frescoes of a Roman representing fresco. a seafront monumental villa; (c) A Roman lighthouse, from a later illustration of a Roman fresco.

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3.2. Opto-Acoustic 3D Reconstruction of the Site Heritage 2020, 3 FOR PEER REVIEW 4 The digital terrain model (DTM) of the underwater archaeological site has been used as a reference for3.2. the Opto-Acoustic creation of the 3D volumetric Reconstruction model of the of Site the villa and the surrounding environment. This solution allowedThe us todigital set the terrain correct model scale (DTM) for the of project the underwater in order to achievearchaeological a very accuratesite has been 3D model. used as a referenceThe DTM for hasthe creation been obtained of the volumetric through a complexmodel of andthe villa articulated and the process surrounding that integrates environment. optical This and acousticsolution techniques allowed us [15 to, 16set]. the In correct particular, scale high-frequency for the project in multi-beam order to achieve equipment a very accurate has been 3D adopted model. to obtain anThe acoustic DTM has bathymetry been obtained of the through whole a submerged complex an archaeologicald articulated process area, whilethat integrates photogrammetric optical techniquesand acoustic have techniques been used [15–16]. to build In a high-resolutionparticular, high-frequency textured 3Dmulti-beam model of equipment the main structures has been of theadopted submerged to obtain remains an ofacoustic the villa. bathymetry The photogrammetry of the whole allows submerged obtaining archaeological an accurate area, 3D modelwhile of anphotogrammetric object (or some architectural techniques have remains, been asused in thisto build case) a usinghigh-resolution photo strips, textured acquired 3D model so that of each the of themmain is partiallystructures overlapped of the submerged to the next remains one. Particularof the villa. software The photogrammetry tools are able toallows recognize obtaining geometric an featuresaccurate in the3D overlappingmodel of an partsobject of(or the some images, architectural transforming remains, them as into in this 3D pointscase) using and arrangingphoto strips, them acquired so that each of them is partially overlapped to the next one. Particular software tools are in the virtual 3D space. The result is a point cloud that reproduces the object’s shape and can be then able to recognize geometric features in the overlapping parts of the images, transforming them into transformed into a 3D surface (mesh). 3D points and arranging them in the virtual 3D space. The result is a point cloud that reproduces the In the case of the Villa dei Pisoni, the optical survey has required a complex strategy, due to the object’s shape and can be then transformed into a 3D surface (mesh). large area to be acquired (about 3600 sq. m.). It has been zoned into regular quadrants of 20 m per In the case of the Villa dei Pisoni, the optical survey has required a complex strategy, due to the sidelarge and area used to as be a acquired reference (about pathduring 3600 sq. the m.). image It has acquisition been zoned activity. into regular The quadrants’ quadrants perimeterof 20 m per was signpostedside and byused cornerstone as a reference tablets path and during ropes the and image then bordered acquisition by activity. different The waterproof quadrants’ markers perimeter (10 per side).was These signposted last have by cornerstone been also used tablets during and ropes the reconstruction and then bordered as a reference by different to alignwaterproof each quadrant markers to the(10 adjacent per side). one These and tolast accurately have been compute also used the duri globalng the scale reconstruction of the 3D model. as a reference A GoPro to Heroalign 4each silver modelquadrant (GoPro, to the San adjacent Mateo, CA,one USA),and to aaccurately consumer-brand compute high-definition the global scale sport of the camera 3D model. with aA 12MP GoPro HD CMOSHero sensor, 4 silver 1 /model2.5” in (GoPro, size, was San mounted Mateo, onCalifornia, a rigid support USA), a and consumer-brand used to acquire high-definition the photo strips sport from a zenithalcamera pointwith a of 12MP view, HD with CMOS a 70%–80% sensor, overlapping 1/2.5” in size, surface. was mounted After some on a colorrigid adjustment,support and theused photos to wereacquire transferred the photo to thestrips software from a Agisoftzenithal Metashapepoint of view, Pro with (Agisoft a 70%–80% LLC, St. overlapping Petersburg, surface. Russia) After [17] to besome processed. color adjustment, The tool recognizes the photos the were features transferre in thed to overlapping the software images Agisoft and Metashape aligns them, Pro (Agisoft creating a spreadLLC, 3DSt. Petersburg, point cloud. Russia) Due to [17] the to huge be processed. quantity Th ofe data tool acquiredrecognizes for the the features Villa dei in the Pisoni, overlapping one single quadrantimages and at a aligns time was them, processed, creating a creatingspread 3D single point spread cloud. Due 3D pointto the clouds,huge quantity later assembled of data acquired into the softwarefor the usingVilla dei the Pisoni, markers one as single reference. quadrant In the at end,a time the was complete processed, spread creating 3D point single cloud spread was 3D processed point againclouds, to obtain later assembled a dense 3D into point the cloud software (more using defined) the markers and finally as reference. a mesh. TheIn the final end, step the is complete the texture mappingspread on3D thepoint model, cloud obtained was processed in Agisoft again Metashape, to obtain aligninga dense again3D point some cloud of the (more photos defined) used forand the finally a mesh. The final step is the texture mapping on the model, obtained in Agisoft Metashape, 3D reconstruction (Figure2). aligning again some of the photos used for the 3D reconstruction (Figure 2).

Figure 2. Optical textured 3D model of the main structures of the submerged remains of the Figure 2. Optical textured 3D model of the main structures of the submerged remains of the Villa dei VillaPisoni. dei Pisoni.

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Heritage 2020, 3 FOR PEER REVIEW 5 In order to complete the final scene, giving a territorial context to the villa, the whole submerged archaeologicalIn order to areacomplete and the the neighboringfinal scene, giving area have a territorial been acquired context to too. the In villa, cases the like whole this, submerged where the areaarchaeological to acquire area is very and largethe neighboring and a full area resolution have been is not acquired necessary, too. theIn cases best techniquelike this, where to use the is acousticarea to acquire bathymetry, is very realized large and through a full resolution small boats is not equipped necessary, with the instruments best technique like ato high-frequency use is acoustic multibeambathymetry, echosounder. realized through small boats equipped with instruments like a high-frequency multibeamIn particular, echosounder. the DTM of the underwater archaeological site has been obtained through a morpho-bathymetricIn particular, the survey DTM carriedof the outunderwater by the Institute archaeological for Coastal site Marine has been Environment obtained (IAMC)through ofa themorpho-bathymetric Italian National Research survey carried Council out (CNR) by the [15 Inst]. Theitute DTM for Coastal of the seafloorMarine Environment allowed us to (IAMC) draw the of mainthe Italian archaeological National featuresResearch of Council the area, (CNR) which [15]. also The include DTM the of military the seafloor complex allowed of Portus us to Iulius draw andthe themain ancient archaeological thermal and features villa complexof the area, of Baianuswhich also Lacus. include The the extraction military of complex archaeological of Portus features Iulius from and DTMthe ancient was achieved thermal thanksand villa to thecomplex use of of a GIS-derivedBaianus Lacus. tool The based extraction on the profile of archaeological curvature algorithm features (Figurefrom DTM3). was achieved thanks to the use of a GIS-derived tool based on the profile curvature algorithm (Figure 3).

Figure 3. Acoustic bathymetry of the Villa dei Pisoni and the surrounding seabed. Figure 3. Acoustic bathymetry of the Villa dei Pisoni and the surrounding seabed. Once the survey activities ended, the optical and acoustic data have been merged by means of a target-basedOnce the survey registration activities approach ended, based the optical on the and detection acoustic of data homologous have been geometricalmerged by means entities of in a bothtarget-based 3D representations. registration approach In particular, based the on location the detec oftion the of optical homologous 3D model geometrical on the acoustic entities map in both has been3D representations. performed thanks In particular, to the geolocation the location of 20 of ground the optical control 3D points model (GCPs) on the belongingacoustic map to the has optical been 3Dperformed reconstruction. thanks to For the each geolocation GCP, 10 measurementsof 20 ground co werentrol takenpoints and (GCPs) a median belonging of the to points the optical has been 3D performedreconstruction. in order For toeach minimize GCP, 10 the measurements errors of the GPS were instrument. taken and Ana median affine transformation of the points has between been theperformed optical andin order acoustic to minimize data has beenthe errors used toof definethe GPS a quantitative instrument. error An affine metric. transformation In particular, thebetween mean distancethe optical has and been acoustic used as data an accuracy has been parameter. used to defin Ane average a quantitative error of abouterror metric. 36 cm has In particular, been obtained. the meanAbout distance the merginghas been of used the two as an diff accuracyerent representations, parameter. An the average operation error has beenof about performed 36 cm byhas means been ofobtained. a selective fitting of the acoustic mesh along the contours shared with the optical mesh. The result is a polygonalAbout the multi-resolution merging of the mesh two on different which some represen manualtations, refinements the operation have beenhas been performed performed in order by tomeans correct of a geometry selective errorsfitting dueof the to acoustic the complexity mesh along of the the reconstructed contours shared scenario with (Figure the optical4). mesh. The result is a polygonal multi-resolution mesh on which some manual refinements have been performed in order to correct geometry errors due to the complexity of the reconstructed scenario (Figure 4).

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FigureFigure 4. 4.View View of of the the multi-resolutionmulti-resolution 3D3D model of the Villa Villa dei dei Pisoni Pisoni and and the the surrounding surrounding seabed seabed usedused as as a a reference reference during during the the virtual virtual reconstruction reconstruction process. process. 3.3. Building the Architectural Model of the Villa 3.3. Building the Architectural Model of the Villa Keeping the multi-resolution 3D model as a reference, the first step of the virtual reconstruction processKeeping was building the multi-resolution the main structures: 3D model the as dock a referenc with thee, the fishponds first step and of the the virtual lighthouse reconstruction at the end, theprocess monumental was building entrance the main in the structures: shape suggested the dock by with the the archaeologists, fishponds and the the perimeter lighthouse of theat the garden, end, the warehousemonumental and entrance the viridarium. in the shape suggested by the archaeologists, the perimeter of the garden, the warehouseA modular and approach the viridarium. has been chosen to build the villa’s different sectors. In the previous experienceA modular of a 3Dapproach reconstruction has been hypothesis chosen to of build a Roman the villa’s villa [12different], all the sectors. main wallsIn the were previous built atexperience once, starting of a 3D from reconstruction the archaeological hypothesis map. of Ina Roman the beginning, villa [12], this all technique the main walls made were simpler built and at fasteronce, starting the building from processthe archaeological but, during map. the texturingIn the beginning, phase, itthis proved technique to be made difficult simpler to manage and faster and notthe building optimized process for the but, game during engines the thattexturing were usedphase, to it render proved the to virtualbe difficult scenario. to manage To solve and these not inconveniences,optimized for the the maingame blocksengines of thethat villa were were used built to as render independent the virtual objects. scenario. In spite ofTo this solve approach these initiallyinconveniences, requiring the a moremain accurateblocks of study the ofvilla the were archaeological built as independent map and more objects. time In to setspite the of work, this itapproach allowed initially us to obtain requiring a more a detailedmore accurate texture study mapping of the and archaeological a lighter and fastermap and final more model. time to set the work,The digitalit allowed reconstruction us to obtain starteda more detailed from the te dock.xture mapping It was built and referringa lighter and to the faster position final model. of the numerousThe digital stone reconstruction blocks located started on the seafrom bottom: the dock. four It long was armsbuilt propendingreferring to towardthe position the sea of andthe connectingnumerous stone on the blocks other sidelocated to aon large the terrace,sea bottom: all supported four long by arms arches. propending toward the sea and connectingIn the archaeologists’on the other side opinion, to a large at the terrace, end of all the supported central dock, by arches. there could have been a lighthouse. Its shapeIn the was archaeologists’ built referring opinion, to some at of the Pompei’s end of frescoes:the central a circular dock, there tambour could bordered have been by a half lighthouse. columns withIts shape Tuscan was order built capitals, referring supporting to some aof beacon Pompei’s of smaller frescoes: columns. a circular tambour bordered by half columnsThe with seafront Tuscan entrance order capitals, of the villa, supporting looking a beacon out on of the smaller big dock’s columns. terrace, must have been monumental,The seafront as many entrance contemporary of the villa, references looking suggest. out on That the is whybig itdock’s was designed terrace, asmust a tall havetriporticus been, openmonumental, towards theas many sea and contemporary composed by thinreferences Ionic columns suggest. supporting That is why a decorated it was designed architrave as and a tall the triporticus, open towards the sea and composed by thin Ionic columns supporting a decorated

Heritage 2020, 3 1205 Heritage 2020, 3 FOR PEER REVIEW 7 architraveroof. However, and the this roof. reconstruction However, th isis onlyreconstruction a hypothesis is only that a could hypoth beesis conﬁrmed that could or be modiﬁed confirmed by theor modifiedresults of by further the results studies of and further archaeological studies and excavations. archaeological excavations. BasedBased on on the the example example of of the the most most part of Roman villas, the archaeologists hypothesized hypothesized that that a a peristyleperistyle with with a a garden garden was was located located at at the the back back of of the the seafront seafront residential residential block, block, followed followed by by a a large large warehousewarehouse for the storage of supplies (Figure 55).).

b (a) ( )

Figure 5. Some images showing the modeling phase: (a–b) the dock and the lighthouse; (c) the Figure 5. Some images showing the modeling phase: (a–b) the dock and the lighthouse; (c) the architrave and the triporticus;(d) the viridarium. architrave and the triporticus; (d) the viridarium. As it appears from looking at the submerged remains of the villa, the viridarium must have beenAs a largeit appears square from space, looking a garden, at the submerged surrounded remains by a partially of the villa, open thequadriporticus viridarium must. On have two sides,been athis large last square seems space, to be composeda garden, surrounded by alternate by square a partially and semicircular open quadriporticus niches;. onOn the two other sides, two this sides, last seemsone presented to be composed half-columns by alternate leaning to square the wall and and se openedmicircular towards niches; the on garden the other with largetwo sides, arches, one the presentedother one ahalf-columns portico with leaning marble to columns the wall [9 ].and This opened sector towards is still to the be studiedgarden with further large and arches, its design the othermay beone reassessed a portico inwith the marble light of columns new observations. [9]. This sector is still to be studied further and its design may be reassessed in the light of new observations. 3.3.1. Texturing of the 3D Model 3.3.1. Texturing of the 3D Model For the texturing phase, a new tool has been used, Substance Painter (Adobe Incorporated, San Jose,For the CA, texturing USA) [18 phase,]. It allows a new the tool creation has been of used, PBR (physicallySubstance Painter based rendering)(Adobe Incorporated, textures, that San is, Jose,textures California, able to USA) react to[18]. the It light allows in athe physically creation of correct PBR (physically way in order based to obtain rendering) more textures, accurate that and is,realistic textures results. able to The react software, to the light thanks in a tophysical the usely ofcorrect the “layer way in concept”, order to obtain allows more us to accurate simulate and the realisticmaterial’s results. wear, The the dust,software, the moss, thanks and to so the on, use contributing of the “layer to give concept”, realism allows to the ﬁnalus to scene. simulate the material’s wear, the dust, the moss, and so on, contributing to give realism to the final scene.

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Heritage 2020, 3 FOR PEER REVIEW 8 The modular modeling technique that has been used to build the different sectors of the Villa dei PisoniThe modularhas made modeling the creation technique of the objects’ that has UV been maps used simpler to build to themanage diﬀerent and sectorsit gave more of the accurate Villa dei The modular modeling technique that has been used to build the different sectors of the Villa resultsPisoni (Figure has made 6). the creation of the objects’ UV maps simpler to manage and it gave more accurate resultsdei Pisoni (Figure has made6). the creation of the objects’ UV maps simpler to manage and it gave more accurate results (Figure 6).

Figure 6. Texturing phase of a column via Substance Painter software. Figure 6. Texturing phase of a column via Substance Painter software. Figure 6. Texturing phase of a column via Substance Painter software. 3.3.2.3.3.2. Modelling Modelling the the Assets Assets 3.3.2.AA Modelling series series of of digital digitalthe Assets 3D 3D objects objects has has been been placed placed in intoto the the virtual virtual reconstruction reconstruction to to obtain obtain a a more more realistic scenario: sacks, barrels, carts, step ladders, cranes, fishing nets, ropes, small boats, ships, realisticA series scenario: of digital sacks, 3D barrels, objects carts, has been step placed ladders, in cranes,to the virtual ﬁshing reconstruction nets, ropes, small to obtain boats, a ships,more statues, and fountains. All the objects have been built and textured separately, sometimes creating statues,realistic andscenario: fountains. sacks, All barrels, the objects carts, havestep ladders, been built cranes, and textured fishing nets, separately, ropes,sometimes small boats, creating ships, more copies of the same object with small variations. For some of them, contemporary references morestatues, copies and offountains. the same All object the with objects small have variations. been built For and some textured of them, separately, contemporary sometimes references creating have have been used (especially for the crane). beenmore usedcopies (especially of the same for theobject crane). with small variations. For some of them, contemporary references Only the statues have been downloaded from the web library Quixel Megascans (Quixel, haveOnly been used the statues (especially have for been the crane). downloaded from the web library Quixel Megascans (Quixel, Sweden) [19] and textured using Substance Painter after a decimation process carried out in order to Sweden)Only [ 19the] and statues textured have using been Substance downloaded Painter from after the a decimationweb library process Quixel carried Megascans out in order(Quixel, to allow them to be rendered in real time in the virtual scenario (Figure 7). allowSweden) them [19] to and be rendered textured inusing real Substance time in the Painter virtual af scenarioter a decimation (Figure7). process carried out in order to allow them to be rendered in real time in the virtual scenario (Figure 7).

(a) (b)

Figure 7. Examples(a) of 3D objects rendered by the virtual reconstruction:(b) (a ) a marble statue; (b) a Figure 7. Examples of 3D objects rendered by the virtual reconstruction: (a) a marble statue; (b) a stone fountain. stone fountain. 4. VirtualFigure Scenario 7. Examples of 3D objects rendered by the virtual reconstruction: (a) a marble statue; (b) a stone fountain. The game engine Unity 3D (Unity Software Inc, San Francisco, CA, USA) has been used to create the virtual scenario representing the Villa dei Pisoni and the surrounding environment.

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Heritage4. Virtual2020 ,Scenario3 1207 The game engine Unity 3D (Unity Software Inc, San Francisco, California, USA) has been used to createFirst, the the virtual architectural scenario representing model of the the villa Villa has dei beenPisoni imported and the surrounding into the framework environment. and an environmentalFirst, the architectural light has been model added. of Then,the villa the DTMhas been of the imported terrain, obtainedinto the throughframework the acousticand an bathymetry,environmental has light been has placed been intoadded. the Then, scene the and DTM manually of the textured terrain, obtained by using through the “terrain the acoustic tool” of Unitybathymetry, 3D. Moreover, has been the placed coastline into andthe thescene sea and surface manually have beentextured added by tousing ﬁnalize the the“terrain virtual tool” scene. of SomeUnity simple3D. Moreover, Roman structuresthe coastline have and been the addedsea surfac to thee have scene, been to populateadded to thefinalize coast the behind virtual the scene. villa. TheSome farthest simple coast’sRoman silhouettes structures have been added placed to as th 2De scene, images to andpopulate made the more coast realistic behind by the adding villa. someThe farthest atmospheric coast’s fog silhouettes to give more have depthbeen placed to the scene.as 2D images Finally, and some made environmental more realistic elements by adding like rockssome andatmospheric vegetation fog have to give been more placed depth along to the the shore scene. and Finally, into the some villa’s environmental gardens. elements like rocksAll and the vegetation assets previously have been created placed have along been the includedshore and in into the the virtual villa’s scenario, gardens. giving it a realistic appearanceAll the (Figureassets previously8). created have been included in the virtual scenario, giving it a realistic appearance (Figure 8).

(a) (b)

(e) (f)

Figure 8. Some rendered images of the virtual scenario: (a) the lighthouse and the sea view pediment Figure 8. Some rendered images of the virtual scenario: (a) the lighthouse and the sea view pediment of the villa; (b) the ﬁshpond; (c) apse-style inner corridor of the viridarium;(d) inner corridor with of the villa; (b) the fishpond; (c) apse-style inner corridor of the viridarium; (d) inner corridor with semi-columns of the viridarium;(e) entrance to the garden from the viridarium;(f) external view of the apse-style corridor of the viridarium.

Heritage 2020, 3 1208

5. Conclusions The virtual reconstruction of the Villa dei Pisoni was an opportunity to deepen and reflect on the plan of the archaeological complex. The adopted architectural choices and the general environmental setting has been inspired by comparisons with contemporary residential complexes in the Phlegrean and Vesuvian areas, deduced from iconographic, archaeological, and literary sources, as well as from the archaeological data of the site. An iterative methodology, based on a 3D reconstruction and modeling approach, has been adopted to support the interpretative modeling step of the archaeological site of the Villa dei Pisoni, simplifying the process of the archaeologists’ feedback on the virtual model. This solution gave a significant improvement in the complex procedure for reconstructing the archaeological structures whose remains are often very few with respect to their original shape. This allowed reaching the best virtual reconstruction solution, helping the archaeologists to better focus their reasoning through a detailed visual representation, and the technical experts to avoid misleading details in the final digital model. We have deeply felt the responsibility to create a product that was scientifically plausible and appealing to the audience’s expectations of its spectacular appearance. In fact, in recent years, 3D reconstructions of individual monuments and entire complexes are increasingly frequent in the media and in popular texts; the public is increasingly crafty and demanding. The responsibility of those working in this field is to maintain the right balance between scientific rigor and the enjoyment of images.

Author Contributions: Conceptualization, B.D.P., M.S. and A.L.; Data curation, M.S. and R.P. (Roberto Petriaggi); Funding acquisition, B.D.P.; Investigation, B.D.P., M.S. and R.P. (Roberto Petriaggi); Methodology, B.D.P., R.P. (Roberto Petriaggi), A.L., R.P. (Raffaele Peluso) and P.D.C.; Project administration, B.D.P.; Resources, M.S. and R.P. (Roberto Petriaggi); Software, A.L., R.P.(Raffaele Peluso) and P.D.C.;Supervision, B.D.P.and R.P.(Roberto Petriaggi); Validation, B.D.P., R.P. (Roberto Petriaggi), A.L. and P.D.C.; Visualization, R.P. (Roberto Petriaggi), A.L., R.P. (Raffaele Peluso) and P.D.C.; Writing—original draft, B.D.P., M.S. and R.P. (Roberto Petriaggi); Writing—review and editing, B.D.P., M.S. and R.P. (Roberto Petriaggi). All authors have read and agreed to the published version of the manuscript. Funding: This research was funded by PON Cultura e Sviluppo 2014-2020–Asse I–“Rafforzamento delle dotazioni culturali”, Azione 6c.1.b (Decr. AdG 18/02/2016 REP 11/16). Acknowledgments: The authors are grateful to all partners and institution that have been cooperating in this part of the Project MUSAS: Parco Archeologico dei Campi Flegrei (Fabio Pagano, Paolo Giulierini, Filippo Demma, Enrico Gallocchio, Luciano Muratgia, Salvatore Carandente), Ufficio Locale Marittimo di Baia, Ufficio Circondariale Marittimo di Pozzuoli, Carabinieri Subacquei–Nucleo di Napoli. Conflicts of Interest: The authors declare no conflict of interest.

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