## 3 Virtual Reconstruction Workflow for Sculptal Fragments
### 3D Modelling and Source-Based Model Creation  
The combination of multiple sources in a virtual sculptural reconstruction process must take into account problems related to the scale and geometry of the involved documents. Figure 9: Schemes of input data: collection of primary and secondary data sources for the _Aescalupius_ (**a**) and _Hyegeia_ (**b**) states’ virtual reconstruction. For SFs are provided museum inventory numbers; documents of secondary data sources are instead identified using progressive numbers for both 2D and 3D sources. In fact, all selected secondary 2D (photos or drawings) and 3D sources (meshes) should be scaled over the main SFs' reality-based model prior to starting the modelling phase, in order to achieve the right proportions between different models. Scaling procedures can be directly conducted in the modelling software both for 2D and 3D sources models, balancing proportion referring to the main SFs' mesh and adjusting scale from different perspectives. Scale optimization may also be provided for a procedure of mesh registration between the SFs and secondary sources. It should be considered that sources images used as modelling references are merely indicative of the final geometry and non-binding, especially when images are affected by strong optical distortions. Moreover, for 3D sources, even if models are geometrically correct, they could be affected by deformations due to the original sculptures themselves, compromising an easy integration between different sources. When 3D source meshes are imported, a preliminary polygons count decimation or retopology can also be considered in order to improve and make easier the management of multiple meshes. They can be superimposed to the SFs' mesh and segmented along with fractures of the reality-based model to isolate fragments useful for the integrations. Then, mesh segments can be joined to the reality-based model by merging vertices of meshes into a single model (source-based model). For this scope, the \"Live booleans\" tool in the Pixologic Zbrush package can be useful to easily merge different meshes into a single model after sectioning them. Sculpting tools are also essential to refine some model details, especially smoothing meshes along the fractures. Once the geometry of the whole statue is reconstructed and optimized with a further decimation process to increase the meshes regularity, the creation of two versions, high and low poly, of the source-based model is recommended for future different applications and scopes (Table 2). As Figure 10 shows, the high poly source-based model of the _[PERSON]_ statue is reconstructed using the meshes of the two main SFs pertaining to the torso and the upper part of the legs (SF. 11045, 11046) and a fragment of a shed foot (SF. 8284). Integrations are mainly carried out thanks to the 3D model of another _[PERSON]_ statue (D. _Ae._ 14) coming from the baths of the Roman villa of Els Munts (Tarragona, Spain) and a head of _[PERSON]_ (D. _Ae._ 13), both available on Sketchfab. According to their similarities, the god of medicine is reconstructed with a long beard and hair; the snake, symbol animal of the god, is wrapped on a long stick on his left hand. The source-based model of the _[PERSON]_ statue is instead created starting from the main fragment of the torso (SF. 8085) to which are integrated segments of 3D models pertaining to one female head from the Roman villa of Els Munts (D. _Hy._ 07) and a female statue from eastern Sicily, exhibited at the Archaeological Museum of Aidone (Italy). Even in this case, the source of the 3D models is the Sketchfab platform. For the high poly models of the _[PERSON]_ and _[PERSON]_ statue, integrations can be clearly distinguished by the real fragments just using textures of the SFs' meshes, according to the theory of restoration and the transparency of virtual reconstruction (Figure 11). However, considering possible declinations for a virtual scenario (e.g., gamification, treasure hunts, itineraries for children, etc.