# Virtual Reality in Cultural Heritage: A Setup for Balzi
## 3 Materials and Methods
### First Iteration of the Balzi Rossi VR Experience  
The first version of the Balzi Rossi VR Experience (Figure 1) was developed using the Unreal Engine 4 graphics engine: it included the \"Caviglione\" and the \"Florestano\" caves. The archaeological site of Balzi Rossi is one of the most important complexes of the Paleolithic European period and, between the 19 th and 20 th centuries, several caves were excavated there. The first step was to import the 3D reconstruction mesh results of the photogrammetry using RC as previously mentioned. The point cloud was then converted into a polygonal mesh of around 250 million triangles. Due to the limited capabilities of Unreal Engine 4 and the hardware at our disposal, it was then necessary to decrease the polygon count of the mesh, bringing it to 250,000 triangles. The reduction was balanced by high-definition texturing, resulting in a model of sufficiently good quality for the purpose of the project at this stage (Figures 2 and 3). Figure 2: Virtual view from Unreal Engine 4 Editor of the first iteration from an air platform above the sea, providing an unusual site perspective thanks to VR. We started with an Unreal 4.27 VR Template, which already has basic interaction, a teleport motion system, forward rendering, and MSAA anti-aliasing implemented by default, settings which are particularly relevant for VR [13]. The 3D model was then imported into it. However, the model was still too complex to be displayed in real time. To solve this problem, it was divided into 25 pieces. Once the model was imported, it was necessary to create a level in which to place it. A number of assets were then added to the level, including an atmospheric system and a landscape that simulated a beach to evoke an environment similar to the Balzi Rossi area, even though at this stage there was not yet a faithful reproduction of the real landscape, except for the cliff. The base area of the level was composed of 24 square planes, each 100 m long, creating an area of 600 \(\times\) 400 m, on which the various sections of the level were built. After modeling the beach, a flying platform was added about 200 m from the shore, which acted as a starting base and a panoramic point. To build the sea, the free asset \"WaterMaterial\" from the Epic games store, containing a collection of assets for crafting rivers, lakes, and seas, was employed. By amalgamating various meshes from this package, a vast expanse of seawater was created, spanning approximately 800 m, to the extent that the water's edge remains unseen in virtual reality. To set up the assets within the level, a selection was made among the materials made available, and the \"M_Ocean_Cheaper\" material was chosen as it was less complex and less impactful on the overall performance of the experience. The technique used to build a consistent sea (despite the material's name) is to use a material involving vertex paint. In this case, the technique was to differentiate the wave motion in contact with the beach and increase or differentiate it as one moves away from the shore. The next step was to make the map navigable. To do this, a series of navigation volumes (NavMeshBoundsVolumes) were positioned, which outlined the areas where teleportation was allowed. Volumes were also positioned to prevent teleportation in areas where players were not supposed to go. The cliff's collisions were then created using simplified collision volumes to allow for better performance. A menu was then added, which allowed two actions: \"Restart\" to return to the initial level and \"Real Life\" to close the simulation. One of the objectives of this project is to highlight the rock art of the archaeological site and show it in a completely new way. In fact, due to the passage of centuries and the cleaning of the sediments present in the caves, some engravings are now in a high position compared to the ground (about 5 m high), making it difficult to observe them closely.