Virtual reconstruction of small architectural forms of the Bogoroditsky Palace and Park ensemble of the estate of Counts Bobrinsky of the late XVIII century

Zherebyatyev Denis Igorevich PhD in History Teaching Assistant of Historical Information Science Department, Lomonosov Moscow State University   108811, Russia, Moscow, Atlasova str., 5, sq. 38 dzher@inbox.ru Other publications by this author

Pimonova Dar'ya Aleksandrovna Master of Arts in History, Graduate of the History Faculty, Lomonosov Moscow State University 119192, Russia, Moscow, Lomonosovsky Prospekt 27, bldg.4 Darpimonova@mail.ru

Introduction

The estate of Counts Bobrinsky in Bogoroditsk (Tula region) is an interesting object of research. It is worth recalling that Alexey Grigoryevich Bobrinsky (1762-1813), the ancestor of the count family Bobrinsky, Major General was the illegitimate son of Empress Catherine II and Grigory Grigoryevich Orlov.

In addition to the unique architectural ensemble, this place was famous for its park, and all thanks to its creator – the estate manager Andrey Timofeevich Bolotov. It was A.T. Bolotov who left the most detailed memories of the construction of the park ensemble, as well as a whole album with sketches of the views of the park, which allows us to present the beauty and grandeur of the estate today.

For the residents of Bogoroditsk, the Bobrinsky estate has always been of particular importance, and a significant part of the city's population is interested in the fate of the A.T. Bolotov Park. The history of the construction and improvement of the Bogoroditskaya estate was previously described by us earlier ^[1].

During the Great Patriotic War, the estate complex was severely damaged. Fortunately, the main buildings were restored in the 1970s, and now there is a museum on the territory of the estate. The landscape park has not been preserved at the moment and needs reconstruction. At the moment, almost nothing remains of the park created by A.T. Bolotov at the end of the XVIII century, the state of the park territory is maintained by the forces of the Bogoroditsky Palace-Museum and Park, as well as the local administration. But the idea of recreating the territory once created by the estate manager is still alive: this is evidenced by repeated restoration projects, the most recent of which dates back to 2015.

Interest in the park is shown not only by residents of Bogoroditsk and the Tula region. The Bobrinsky estate has the status of an object of cultural heritage of federal significance, an important tourist object not only of the Tula region, but also of the whole of Russia. The album of A.T. Bolotov with views of the park is kept in the State Historical Museum in Moscow, which undoubtedly speaks of the high importance of the Bogoroditskaya estate and the park. In such conditions, the creation of a virtual reconstruction of a landscape park has become a truly urgent task.

Thus, the purpose of this work is to restore the appearance of the landscape park and create its virtual reconstruction. The emphasis is on the reconstruction of small architectural forms: underground grotto, rotunda, gazebos, nurses, artificial cave, etc.

Overview of sources

One of the most important sources of this work is the memoirs of the creator of Bogoroditsky Park Andrey Timofeevich Bolotov, published under the title "The Life and Adventures of Andrei Bolotov. Described by him for his descendants" ^[2]. These memoirs were created by A. T. Bolotov for more than fifty years and exist in fifty manuscripts.  "Adventures" is published in four volumes and is a detailed account of the life of Andrei Timofeevich. This source is not only a storehouse of information about the biography of its author and about the history of the Bogoroditskaya estate. A. T. Bolotov is a man who had a real passion for garden art. While engaged in the construction of the park in Bogoroditsk, he described in detail the process of its creation, which makes memories a really valuable source when creating a virtual reconstruction of the park.

The most important addition to A.T. Bolotov's memoirs about the park are drawings of views of the Bogoroditskaya estate. The State Historical Museum has preserved a whole album of watercolors and sketches made by the estate manager together with his son ^[3]. The album was being prepared for showing to Empress Catherine II, and therefore many of the drawings in it are made really qualitatively and worked out in detail. These images give an exhaustive idea of many parts of the landscape park; most of the objects, small architectural elements in the drawings are depicted from different angles, which allows you to understand their design much better, determine the location and features of the relief, plantings in specific places.

Among the fine materials, it is also worth noting the collection "Monuments of Art of the Tula province" ^[4]. The collection contains a large number of photographs, plans and drawings depicting the objects of the Bogoroditskaya estate. There are individual photographs and drawings of small architectural forms, which were used, in particular, in the latest documents on the restoration of the park.

A separate set of sources, without which a historical study devoted to the visualization of cultural heritage objects is impossible – these are plans and drawings. There are several preserved in the collection of the Bogoroditsky Palace Museum and Park, and, conditionally, they can be divided into two groups: those that were created directly in the XVIII century, as well as more modern reconstruction plans.

Among the first group, it is worth noting such sources as:

· plan-drawing by A. T. Bolotov, made in 1784 ^[5];

· the plan of the Bogoroditsky Garden of 1785 ^[6];

· the plan of 1785, preserved in the Museum of the History of St. Petersburg, in the collection of drawings by Ivan Egorovich Starov ^[7].

Among the modern sources , the following plans and drawings were used:

· a working project for the restoration of the hydraulic system of the A. T. Bolotov park, carried out by the company "M P Ecoproject" in 1993 ^[8];

· reconstruction plan submitted by the institute "Special Project Restoration" ^[9];

· plan-reconstruction of Bogoroditsky Park, executed by I. Yarov ^[10];

· Master plan of the central part of the park. Restoration in 2015 ^[11].

Of particular value for this study are the latest reconstruction projects of the park. The first of them – the project of Restoration and Architecture LLC in 2014 ^[12] includes a detailed plan for the reconstruction of the park, taking into account modern features.  The scientific and design documentation consists of 5 volumes and contains a large number of drawings, including drawings of individual small architectural forms and terrain plans.

Another restoration project of the park, or rather part of it, was created in 2015 by LLC "Ekovodstroyproekt" ^[13]. The scientific and design documentation was created in order to recreate the cascade of ponds in the "Echonic Valley" of the A.T. Bolotov Park. In this regard, the main part of the documentation is devoted to geological, geodetic and hydrological studies, as well as tools and techniques for landscape restoration.

Virtual reconstruction of an underground grotto

A.T. Bolotov describes in detail the construction of an underground grotto on the territory of the landscape park of the Bobrinsky estate in the twenty-first part of his memoirs. The governor M.N. Krechetnikov, walking with the steward through the park under construction, noticed a large pit and recommended A.T. Bolotov to fill it up. However, Andrey Timofeevich had other plans for this space. His idea was "to make a decent underground grotto in this place and arrange and arrange it so that it was completely inconspicuous from the outside" ^{[2, vol.3, p.1171]}. Immediately after the visit of the governor, the steward began to implement his idea, and ordered the carpenters to build a "fairly spacious" four-cornered log house, and the workers to dig a bigger hole under it so that the log house could be lowered as deeply as possible. There were two entrances to the grotto, both dug underground, one was "shorter, in four steps, the other longer" ^{[2, vol.3, p.1171]}. The roof was a dome-like structure. From above, the resulting building was covered with earth in order to "give this place rather the appearance of only a small hillock, with a marble statue placed on it on a pedestal" ^{[2, Vol.3, p.1171]}.

As for the interior of the grotto, the memoirs of A.T. Bolotov tell us the following: inside, the space of the grotto was an octagon, consistent with the dome roof. This form was achieved with boards that fenced off the corners of the grotto. Niches were made in the fences, which simultaneously acted as nurses. At the entrances, "decent glass doors" were installed ^{[2, vol.3, p.1171]}, and opposite them were the same fake ones, in which the glass was changed to mirrors. So, A.T. Bolotov achieved the effect of increasing space. Entering the grotto, it seemed to the visitor that other rooms were hidden behind the doors. Moreover, such doors have also become a joke – a person looking at himself in the mirror thought that another guest was moving towards him.

Since the grottos in the park art tried to make them as similar as possible to natural ones, their walls were often decorated as stone caves and decorated with various stone materials. The grotto of A.T. Bolotov was no exception. The steward ordered the walls of the grotto "to be plastered decently and to cover the whole tree with plaster so that it would not be noticeable at all" ^{[2, vol.3, p.1176]}. A large cornice was hung under the dome, and then followed a lot of work on decorating the walls with shells collected by Andrey Timofeevich's son on the banks of the Oka River.

In addition to the memoirs of A.T. Bolotov, information about the appearance of the grotto can be obtained from his drawings. In the album you can find several images of the grotto "outside". The best displayed, of course, is the most picturesque western entrance, which can be seen in four sketches. Three of them show the entrance "from the street" from different angles, from the side of the palace, on the way to the palace, as well as from the side of the big pond. One of the drawings depicts the exit from the grotto to the park, where a beautiful view of the city opens ^[3]. The view of the northern entrance opens to us only in one drawing by Bolotov. Another one shows a view of the grotto hill with a bust of a Satyr. This is the only color sketch of the grotto. It gives an idea of what the hill above the grotto and the space around it looked like.

Memories and drawings by A.T. Bolotov, for all their colorfulness, do not give a complete picture of the appearance of the grotto. In addition to this information, there are plans that make it possible to determine the location of the grotto as accurately as possible, as well as a drawing of the hill above the grotto created within the framework of the Restoration and Architecture project ^{[12, Vol.4]}. The drawing consists of three fragments depicting the relief of a separate part of the park: a topographic plan and two relief images in the section by different axes. It is worth noting that the restoration project of the park, being developed in 2014, was not supposed to restore the grotto, and therefore there are no drawings for its design. However, the document describes how the grotto was created and indicates its approximate dimensions based on archaeological, geological data. Thus, the drawing of the hill above the grotto seems to be a valuable source that allows you to more accurately restore the dimensions and location of the building, as well as recreate the exact terrain, including the height of the hill itself. 

Within the framework of historical research, the creation of any 3D model begins with the preparation of sources. First of all, this is the preparation of drawings for import into the SketchUp program, where the drawing will be drawn and further modeling. In the case of reconstruction of the hill above the grotto, there was only one drawing in the entire source database, mentioned above. The materials of the scientific and design documentation developed by the specialists of Restoration and Architecture were scanned during a visit to the Bogoroditsky Palace Museum and Park in parts on an A4 scanner, and then "glued" in Photoshop using the Photomerge function.

Fig.1. Details of the master plan. The hill above the grotto. Source: materials of Restoration and Architecture LLC Scientific and design documentation.

Next, the drawing was uploaded to the SketchUp program (Fig.1). The virtual reconstruction of the grotto began with the creation of a 3D model of the terrain in which the structure is located. According to the topographic plan of the hill above the grotto, all the isolines were circled using arcs, and then raised to the required height. Using the sandbox tool, all the isolines were connected into a single relief (Fig. 2). On this relief, the point of the center of the grotto, where the pedestal is located, was marked.

Fig.2. Three-dimensional model of the relief of the hill above the grotto.

The next stage was the creation of the grotto structure itself. Its exact dimensions are not indicated in any source, however, we know that the walls of the grotto were a wooden log house, respectively, its dimensions were limited by the size of logs. Log cabins often had typical dimensions, and, most likely, the size of A.T. Bolotov's grotto in terms of was about 5 meters in length and width. The same conclusions were made by specialists of Restoration and Architecture LLC, who, in addition to historical sources, were guided by geological survey data.

So, in the SketchUp program, a 5x5m log cabin model was created. The dimensions of the wooden boards were calculated along the length of the inner walls in such a way that when they were placed in the corners of the room, a regular octagon was obtained. Based on the data obtained on the required size, planes were placed inside the grotto, which formed an octagonal shape of the room. Niches were "cut" in the corner walls. Their size was calculated based on A.T. Bolotov's drawing. Despite the fact that the perspective of the sketch is quite distorted, the image remains the only authentic source that conveys the appearance of the interior space of the grotto. Bolotov's drawing was uploaded to SketchUp and combined with the model. According to the proportions of the image, the size of the niches was calculated, their depth was taken into account the typical size – 30 cm. Niches were designed not only for beauty, nurses were also arranged in them, so the depth of the niche is quite suitable for the arrangement of a sitting place.

The entrances to the grotto in the SketchUp program were modeled as one-way tunnels. The length of the entrance passages was restored in accordance with the description of A.T. Bolotov. The western entrance, according to his recollections, was 4 steps long, i.e. about 2.8 m, and the northern one was "longer", its size was calculated based on the drawing of the hill above the grotto, and then clarified when creating a virtual reconstruction.

The roof of the grotto was an oak octagon, like the vault of a dome. In the SketchUp program, a similar dome was designed, its height was built in accordance with the drawing. A "turf" hill adjacent to the relief was modeled from above. Due to the fact that in the Twinmotion program (where the model was later uploaded to create a common visualization scene) there are no tools to create underground facilities, the hill had to be provided in advance.

A pedestal with a marble statue was placed on the hill. The pedestal of the grotto was made of glass and acted at the same time as a lantern, letting light into the grotto. At the same time, the pedestal frame itself was most likely brick and covered with plaster. The dimensions of the pedestal and its shape were taken from the drawing of the Laton Bridge ^[14].  After modeling the frame, a glass cube was placed inside the pedestal, on which the statue stood. Rectangles were formed in the windows of the lantern – future iron sheets.

The next stage was the creation of a "penetrating picture" in an iron sheet. As A.T. Bolotov mentioned, many round holes were made in the iron sheet, into which "multicolored penetrators" were inserted that let light into the grotto, that is, most likely they were small colored glass. If you look at the drawings of A.T. Bolotov, you can see that in these iron sheets on the pedestal there was a picture in the form of a wreath. 

To create a similar drawing on a 3D model of a pedestal, an image was selected, which acted as a sample, loaded into the SketchUp program and placed on a future model of an iron sheet (Fig.3). Next, a hole template with colored glass was created. Enabling the "X-ray" mode, which makes the model translucent, through repeated copying of the template, it was possible to create a wreath pattern on an iron sheet.

Fig.3. Reconstruction of the drawing on the iron sheets of the pedestal.

According to the memoirs of A.T. Bolotov, mirrors were placed inside the pedestal, which conveyed to the viewer inside the grotto the view of the city and the park, that is, the pedestal-lantern also acted as a periscope. The controller did not show exactly how this design looked, so when restoring it in 3D, it was necessary to think over several possible options. In SketchUp, four different versions of the pedestal with mirrors inside were created (Fig. 4).

Fig.4. Options for the arrangement of mirrors in the pedestal.

To check the "operability" of all structures, as well as software, an optical experiment was conducted in various programs designed to visualize 3D models. The programs Twinmotion, Lumion and Unreal Engine were selected for the experiment. According to the results of the experiment, only the Twinmotion program showed the correct result of working with mirrors (Fig.5). Of the four variants of the pedestal, only a pedestal with a large mirror turned out to have a truly readable display, the design with a prism of four mirrors also showed good results, but the picture reflected by it looks more like a kaleidoscope than a bright panorama of a city and a park.

Fig.5. Optical experiment with mirrors in the Twinmotion program.

As a result, the choice of the mirror design of the lantern was reduced to two options. Analysis of A.T. Bolotov's drawings revealed that the pedestal was covered with iron sheets with a wreath pattern on all sides. Therefore, the option of a large mirror instead of one of the sheets is hardly possible, besides it would be quite impractical, because initially iron sheets were supposed to protect the glass from breaking. In addition, the design with four mirrors would be more justified, due to the fact that in the memoirs of Andrei Timofeevich "mirrors" are mentioned in the plural. Thus, the design of the pedestal was chosen.

There are practically no sources about busts in the park of A.T. Bolotov. The creator of the park himself tells little about them, it is only known that the marble statues were purchased by the previous steward in St. Petersburg on ships. In this regard, it can be assumed that all the purchased statues were brought from abroad, which means that they most likely represented typical sculptures used to decorate gardens or residential premises. The most popular decoration of gardens both in Europe and in Russia were sculptures of ancient Greek and Roman gods and nymphs. Therefore, it was decided to use models from the Sketchfab online library for the reconstruction of park busts ^[15]. However, it is worth noting that an accurate reconstruction of all the sculptural compositions on the estate is impossible, and the models used do not claim to be scientifically reliable.

The creation of the external structure of the grotto was followed by a virtual reconstruction of its interior (Fig.6). Here, first of all, it was necessary to restore the doors, which were an important part of the interior decoration. There were four of them, while two of them were entrance, and two were fake, with mirrors inserted instead of glasses. Doors are a typical element and most often have standard dimensions. Most likely, they were not purchased specifically for the grotto, and therefore were of the same type with the doors of other structures of the Bogoroditskaya estate. Similar double-leaf doors with a large number of glasses were used to create a stone greenhouse, they eventually became the prototype for the design of entrances to the grotto. In the fake doors, the texture of the glass was replaced with mirrors, and the handles were also removed, otherwise they were similar.

Fig. 6. View inside the grotto. Bolotov A.T. Source: "Types of the Bobrinsky Bogoroditsk estate". 1786

A "large cornice" was hung under the ceiling of the grotto. There were no drawings for the interior of the grotto, but the cornices were hardly made by hand, so it is also possible to use analogues from neighboring structures. For example, a detailed image of the cornice is contained in the drawing of the stone pavilion of the gazebo, made by the project "Restoration and Architecture" ^[14] according to information from the book by Hirschfeld, from where Bolotov drew information about the construction of a landscape park. The design of this cornice was used for the grotto.

The most difficult part of the reconstruction of the grotto is the interior decoration of the walls and ceiling. According to the sources at our disposal, namely a pencil drawing and a fragment of memories, it is possible to restore an approximate shell pattern. However, the use of analogues is necessary here.

The closest analogue of Bolotov's construction is a grotto built in Moscow's Kuskovo Park around the same period. It was finished by the German master Johann Focht in 1761-1775 . Today, the grotto in Kuskovo is the only one that has preserved its historical appearance. Most recently, its three-year restoration was completed. Inside, the pavilion is a central circular hall surrounded by two offices. As with A.T. Bolotov, the author's idea was to make the grotto look as much like a cave as possible inside. The walls were covered with various materials, including tuff, sand, moss, pieces of crushed glass and mirrors. But the "highlight" of the grotto was its numerous decorative ornaments made of shells of 24 different species collected from all over the world: the Mediterranean, Red, Japanese and Black Seas, as well as reservoirs of the Moscow region ^[16].

Of course, the grotto of A.T. Bolotov could not boast the same wealth. The shells used by the steward in decorating the walls were recruited by his son on the banks of the Oka River, most likely there were two or three types of them – these are, first of all, toothless and pearl-pearl shells (Fig.7). Nevertheless, some analogies, principles of construction can still be carried out, and also take sample of the wall material: colored sands, broken glass, mica.

Fig.7. Common toothless (a genus of freshwater bivalves).

It was decided to transfer the shell decorations of the grotto in geometric three-dimensional forms to SketchUp, having previously applied the textures of the shells painted in golden and silver color. The seamless texture was created in Photoshop. The textures were imported into a three-dimensional modeling program and applied to shell models, then their "laying out" on the wall according to A.T. Bolotov's drawings began. The drawing was laid out along the perimeters of niches and doors, as well as on the ceiling. On each wall there is a pattern of shells on both sides, decorated with a decorative element in the form of a flower on top. In addition to shells, square elements are also used in these patterns, probably large pieces of glass or mirrors.  In the niches, A.T. Bolotov created whole compositions – "festoons hung on cords made up of large white, like beads, pierced" ^{[2, vol.3, p.1177]}. These compositions were created according to Bolotov's drawing with the help of repeated copying of shells. Separate models of "large white penetrations" were created for the "cords". Materials of sand, broken glass and mica were applied to the walls.

Virtual reconstruction of "marble" caves

One of the first ideas of A.T. Bolotov in Bogoroditsky Park was the creation of a whole system of artificial caves. The idea arose when the steward, studying the territory, discovered "marble sands". On the very shore of the pond in front of the palace there was a large mountain of packed hard sand. In its structure, it resembled marble, since nature "added colors", and the sandstone was all covered with multicolored iridescent veins.

A.T. Bolotov, who always believed that during construction it was necessary to "consult" with nature, to create such parks that would not destroy the entire natural landscape, but, on the contrary, emphasize it, simply could not pass by such a miracle. In order to show in all its glory this amazing mountain created by nature, he came up with the idea of "cutting into its interior some kind of bright and spacious, and walking-friendly caves" ^{[2, vol.3, p.1177]}. And in order to give the place an even more beautiful and neat appearance, the steward decided to decorate the cave externally in such a way that it appeared as "a magnificent and majestic ruin of a certain underground building, with entrances to it along the porches, with steps and remnants of broken columns, part of the cornice and with several doors and windows" ^{[2, vol.3, p.1177]}.

In the notes, A.T. Bolotov does not describe the detailed process of creating caves. Naturally, there were no drawings or plans for the cave, because when working with the park, the manager usually immediately put his ideas into practice without writing them down on paper. According to the memoirs of A.T. Bolotov, it is only possible to pick up the materials of the cave and roughly guess what the structure was like.

The only source that allows you to restore the appearance of the caves in front of the palace are drawings from the album of A.T. Bolotov. When creating a virtual reconstruction, a detailed analysis of his watercolors and comparison with the plans was carried out.

You can take a closer look at the structure and understand the approximate design and plan of the internal structure of the caves on two colored watercolors. Conditionally, it is possible to divide the structure into three levels:

1)    The first, the lowest, looks like a kind of "half-floor". Here you can see two small entrances to the caves, which were clearly smaller than a man's height. The functional purpose of these passages is unclear, because an adult will not be able to pass through it. Perhaps it was a basement floor, or it could just be deep niches. The space between the two entrances is delimited by a protruding platform, on the left side of which there is a composition cut in the same sandstone.

2)    The second level represents those "bright and spacious caves, convenient for walking". They are built in the best and most beautiful layer of sandstone. Here you can see three entrances to the cave. The first one, depicted in the picture on the left, is decorated with facing stone, a separate staircase leads to it. The central entrance is drawn and is somewhat less visible, as it is hidden by a protruding wall with fragments of columns. The third entrance is located to the right behind the mentioned wall. On the landing in front of the third entrance there is a small path along which you can walk, it leads to a separate large staircase.

3) On the third tier, wide low niches are visible, to which it was hardly possible to approach or climb the stairs. The probable function of these niches will be discussed further.

In the figure you can also see a large number of fragments of columns and specially created ruins (Fig.8). All these figures were created by A.T. Bolotov and his son from the remains of boulders that were carved when creating caves. With their help, the author managed to give the building a special look and create the atmosphere of a ruined antique building. On the right, the cave is bounded by a high sheer cliff.

Fig.8. "View of ruins and caves carved from marble sand in the Bogoroditsky garden". Bolotov A.T. Source: "Types of the Bobrinsky Bogoroditsk estate". 1786

Another drawing shows the view of the cave, if you walk from it a little further towards the park. Here you can see a large waterfall passing from a large stone pavilion (Fig.9). A little higher, approximately at the level of the second tier of caves, there is a large stone arch inscribed in the relief of the rock. Behind the rock, you can see the right side of the caves from a different angle. Here you can clearly see the space between the third entrance and the large staircase. There were two semicircular niches in it, separated by semi-columns.

Fig.9. "The scene presented to the vision standing at the bottom of a large waterfall."

Bolotov A.T. Source: "Types of the Bobrinsky Bogoroditsk estate". 1786

The appearance inside the caves is shown in two drawings. One of them shows a new entrance to the "ruins", hidden in other drawings. You can see it if you go through a large stone arch. The second one shows a view inside the cave, according to which you can make the layout of the "floor" (Fig.10).

Fig.10. "View of the interior of caves carved into a mountain of marble solid multi-colored sand consisting of". Source: Bolotov A.T. "Types of the Bobrinsky Bogoroditsk estate". 1786

The virtual reconstruction of the "marble" cave was created almost exclusively from watercolors using analogues. The dimensions of passageways, stairs and other structures were calculated relative to the people depicted in A.T. Bolotov's drawings. It should be noted right away that the analysis of other images from the album showed that the author quite often resorts to distortions of perspective and the size of his structures. It is possible that in the case of caves, this also applies. However, in the absence of other data, restoring the dimensions by comparing the proportions of watercolors became the only possible option.

All cave images were uploaded to SketchUp using the Match Photo function. This tool allows you to put several photos or other images in the correct angle relative to the model and create an object by "copying" it from the picture (Fig.11-12). The creation of a 3D model was started from the second tier, that is, from the caves themselves, cut for guests to walk, as they are best reflected in watercolors. According to several drawings, the passages were restored, a plan was created for how the caves looked like communicating with each other.

Fig. 11. Reconstruction of the cave entrance from a large waterfall using the Photo Match tool in SketchUp.

Fig.12. Reconstruction of the interior layout of caves using the Photo Match tool in SketchUp.

Fig.13. Internal layout of cave tunnels.

After modeling the second tier of caves, the reconstruction of the third level began (Fig.13). The upper niches, judging by the drawing, were deeper than the entrances to the caves, that is, most likely located above the distant tunnels. After analyzing the appearance of similar grottoes and artificial caves in the history of landscape art, we found out that light wells are a common element in the construction of such structures. They perform the functions of lighting, as well as ventilation of the room. Similar light wells are present, for example, in the grottoes of the Grand Cascade in Peterhof.

It is logical to assume that similar light wells were also used by A.T. Bolotov when creating "marble" caves. Without them, being in the room would be little possible due to the lack of normal ventilation, and it would also make no sense without lighting, because the idea of the manager was that in the caves the audience would have the opportunity to see the beautiful structure of sandstone as best as possible.

The niches themselves, in turn, were most likely made in order to protect the light wells from rain and the ingress of earth, which could crumble from a high cliff. This is how light wells in tunnels were modeled, their location was determined through the Match Photo function (Fig.14).

Fig.14. Reconstruction of niches and light wells of the upper tier of caves in SketchUp.

When restoring the lower tier using the Match Photo tool, the location of small niches-entrances to the cave was indicated. In the drawing by A.T. Bolotov, deep shadows are used inside these entrances, which gives reason to assume that not just niches were located in their place, but there was a passage inside. Therefore, during the reconstruction, it was decided to make a connecting tunnel between the two entrances and present it in the form of a basement with a staircase descent so that a person could pass inside. Note, however, that this is only one of the possible interpretations of the drawing. There are no additional sources to accurately recreate this part of the cave.

Fig.15. Reconstruction of the possible layout of the lower tier of caves in SketchUp.

The creation of the lower tier also involves the restoration of stairs leading to the "large" entrances to the cave (Fig. 15). There were three staircases, two of them can be easily seen in A.T. Bolotov's watercolors. The third staircase leading to the central entrance is "hidden" in the watercolor behind the ledge of the lower tier. We can see a small fragment of it: on the first step there is one of the guests of the park, who, most likely, rises to the cave.

After the restoration of the entire structure of the cave, it was necessary to finalize individual details: add decoration of the entrances with stones, create and arrange models of ruined columns, vases and other objects that convey the appearance of a "magnificent and majestic ruin".

Virtual reconstruction of the rotunda and nurses

Despite all the perfectly embodied ideas of A.T. Bolotov in the park, the governor M.N. Krechetnikov, walking through the garden, noted that he lacked "gazebos and garden buildings." Inspired by Hirschfeld's books on gardening, the steward was extremely pleased with such a proposal from his boss. The very next day, he showed the governor several selected projects of gazebos, as well as places in the garden where they could be put.

So there was a round gazebo rotunda and two nurses – "noon" and "evening". These architectural elements have received a worthy place in the album of A.T. Bolotov. Based on his drawings, drawings of these small architectural forms were prepared within the framework of the Restoration and Architecture project. Based on them, we created three-dimensional models in the SketchUp program.

Modeling of the rotunda began with the creation of a symmetrical gazebo base with steps according to the dimensions indicated in the drawing (Fig.16-17). A roof model was created separately. Standard Corinthian columns were added from the 3D Warehouse online library. The models of these columns were modified taking into account the size of the rotunda, missing elements present in the drawing and watercolors were added. The textures of plaster and white stone were applied to the model, the texture of red paint, matched by the color of watercolors, was applied to the roof. The finished model was grouped and saved for further unloading into the general scene of the park in Twinmotion.

Fig.16. Reconstruction of the rotunda in SketchUp.

Fig.17. Reconstruction of the rotunda in SketchUp. The capital.

To create a 3D model of the "midday" nurse, all available drawings were prepared through Photoshop and uploaded to SketchUp. Then they were adjusted to scale and placed in the correct projection relative to each other. The plan of the nurse was outlined with lines and a plane of the correct dimensions was created, repeating the contours of the nurse. Further, each separate part of this plane was raised to the desired height in accordance with the drawings of the side facade and the section. Curved railings were worked out separately. The cornice and the edge of the nurse were outlined according to the drawing and stretched across the entire width of the structure.

A similar sculptural composition of an angel was found in the online library of 3D models Sketchfab. The model was created on the basis of photogrammetry technologies based on a museum exhibit in the Agisoft Metashape Professional photogrammetric program. The busts on the bench railing were taken from the 3D Warehouse online library, imported and delivered at the right scale.

Fig.18. Reconstruction of the "midday" nurse in SketchUp.

The process of reconstruction of the "evening" nurse (Fig.18) differed from the "afternoon" only in the number of projections used: within the framework of the project "Restoration and Architecture", a drawing of the nurse's plan was not prepared. This is probably due to the fact that the "evening" nurse has a simpler geometric shape, which is much easier to imagine and restore. Otherwise, the method of creating the model was absolutely identical. The sculptural composition of the angel is the same. This is due to the fact that in the drawings of A.T. Bolotov there is no way to determine exactly which sculpture was taken during the construction of the nurses. In watercolors, you can only see the figure of an angel in a reclining position. Festoons as a typical sculptural element were duplicated from the model of caves, where they were used to create a commemorative plaque on the lower tier (Fig.19).

Fig.19. Reconstruction of the "evening" nurse in SketchUp.

Virtual reconstruction of the "snail"

A special idea of A.T. Bolotov was the creation of the so-called turf "snail" - water fun. It was a small hill with a path, climbing up to which in advance, at the command of the steward, the gardener opened the lock that closed one of the streams of the middle pond. The water from the sluice flowed quickly and created a wide water moat, which it was impossible to jump over. Such amusement rides were very popular in parks and caused a lot of positive emotions among visitors.

Andrey Timofeevich's water fun is described in detail in his memoirs, however, not a single visual evidence of it remains. There is no turf snail in any drawing of the steward.  According to the "notes" of A.T. Bolotov, it is possible to restore the location of the "snail", since visiting this attraction was part of the route along which the creator of the park conducted the governor M.N. Krechetnikov

A possible version of the appearance of the "snail" was developed by the restoration project of the park in 2014 ^[18]. It was he who formed the basis of the three-dimensional reconstruction of the object. The drawing of the water fun shows in detail the park element from different projections: it contains a topographic plan of the surrounding area, a plan of the "snail" itself, as well as an image of it in two sections and a section of the trail (Fig.20). In addition, detailed notes on materials for the construction of the attraction, instructions on the process of recreating in real the park.

Fig.20. Details of the master plan. Snail Hill in a romantic park. Source: materials of Restoration and Architecture LLC. Scientific and project documentation.

The creation of a three-dimensional model of the "snail" was carried out, as in previous cases, in the SketchUp program. The prepared fragments of the drawing were imported into the program, placed at the correct scale relative to each other. Then the reconstruction of the relief according to the topographic plan began. The technique of its virtual reconstruction is similar to recreating a fragment of the relief of the hill above the grotto. After the relief was created, a snail plan with paths was outlined. The SketchUp program has rather limited functionality when creating models of complex spiral shapes. To create a model of the "snail", the cut drawings marked the points of the height of the path. Further, the outlined plane was raised by separate points; so the model took the form of a spiral (Fig.21). For the park idea, a three-dimensional image of the path was formed separately and the hill itself, along which the path passed. The created model has been textured and prepared for import into Twinmotion.

Fig.21. Reconstruction of the "snail" in SketchUp.

Collecting the general scene of the park

To present the overall results of the work and create visualization, all the created three-dimensional models were imported into the general scene of the park in the Twinmotion program, where their final version was finalized (Fig.22-23). When creating a virtual reconstruction of small architectural forms of a landscape park, it is not enough to develop only three-dimensional models, since they are often an integral part of the overall landscape, together with water decorations, green spaces and other elements. The grotto, the "marble" caves, the "snail" were also part of the relief.

22. The hill above the grotto with a towering marble statue on a pedestal in Twinmotion.

First of all, when creating a common scene, the ponds of the park were created. They were planned according to a specially scaled texture of the master plan. In the Twinmotion program, you can "draw" on the relief with various materials. With the help of the gravel texture, the outline of the ponds was outlined according to the park plan. By disabling the visibility of the layer with the plan, it was possible to see the contours of the pond. Then, using the tools of work on the relief, depressions were created on the site of reservoirs that needed to be "filled" with water. To create water in ponds, primitives were used, on which water material was applied.

After creating the ponds, all the created three-dimensional models were imported into the scenes and put in the right places according to the plan. After that, the design of each model and the work with the relief of watercolors began.

Fig.23. View of the western entrance of the grotto and the rotunda in Twinmotion

 Rice.24. View inside the grotto in Twinmotion.

For example, the work with the grotto was carried out as follows (Fig.24). A recess was made in the relief on the site of the grotto, since the structure is underground. The building was lowered into the recess, then the relief was leveled so that its texture merged with the hill created in SketchUp. The entrances were decorated with a large number of stones, they were laid out so as to close the texture of the tunnel and make the model three-dimensional. For the rotunda, standing not far from the grotto, a cliff was created near the pond, which was also decorated with stones. Vegetation around the objects was arranged in accordance with the planting drawings ^[19], as well as watercolors. Such work was carried out on each object. Each drawing from the album of A.T. Bolotov was analyzed from the point of view of the angle in the park from which it was drawn. Then the work was carried out with the relief and the plants were "planted" (Fig.25).

Fig.25. View of sand caves from the side of a large pond in Twinmotion.

Thus, a three-dimensional historical reconstruction of small architectural forms, the relief of the park, reservoirs and green spaces was carried out. Now, to demonstrate the work carried out, it was necessary to create a general architectural visualization of the palace and park ensemble of Count Bobrinsky's estate in the Twinmotion program. The Twinmotion functionality, designed specifically for architectural visualizations, provides a wide range of software tools for creating a 3D scene. At the visualization stage, the program included modes for rendering the sky, shadows, and atmospheric effects. The camera angles of the renderers were chosen from the same points from which the estate manager A.T.Bolotov painted his watercolors. Further work was mainly mechanical and does not need additional description; a complex of images of the palace and park ensemble of the estate of Count Bobrinsky of the late XVIII century was created., several panoramas of the estate complex were also created, intended for further publication on the Internet. Thus, the restoration of the external appearance of the architectural complex was completed and the set goals were achieved.

At the moment, the Bogoroditsky Palace-Museum and Park do not have a model of the entire estate at the end of the XVIII century among the exhibits. The created virtual reconstruction of the most beautiful part of the estate park can be included in the number of digital exhibits of the museum. The results of the study can be presented in the multimedia space of the State Historical Museum, where an album with drawings by A.T. Bolotov is stored, as well as on various multimedia platforms such as YouTube, Twinmotion Cloud, etc.

The authors of the article express gratitude to Marina Vladimirovna Zherzdeva, head of the branch of the Tula Museum Association - Bogoroditsky Palace Museum and Park, and to the museum staff represented by Olga Vladimirovna Perova, head of the Cultural and Educational Department, for their assistance and assistance.