## 3 Proposed Pipeline
### Inspect
Through the base functions of the collaborative component, it is possible to see other analysts in the 3D space (as avatars), talk (spatialized audio streaming) or chat  
Figure 4: Sample inspection in the Web3D tool “_Merkhet_”. Top row: loading of 3 different records (users’ sessions on single 3D object, three different colors) from hub via user interface; bottom row: time slider on active record. and use a shared pointer (e.g., to direct the attention of other analysts to specific areas). Furthermore, such a component, offered by ATON, allows one to build custom distributed logic for the IA tool, to additionally broadcast custom events to other connected analysts. For Merkhet specifically, we designed a set of collaborative events regarding the loading of records, aggregates and time synchronization for records (e.g., when one analyst changes the current time of the active record, all remote analysts are synchronized). Thanks to WebXR, Merkhet allows augmented/mixed reality inspections, to perform the in-depth, 6 DoF exploration of volumetric data in physical spaces. Immersive VR headsets can be used, for instance, to load volumetric data aggregates and inspect and query them in the virtual space (see Figure 5A,B). Mobile devices such as smartphones can also be used to inspect user sessions in AR (see Figure 5C), moving around the virtual object and user record in the physical space. It is also possible to use mixed reality (for instance, using devices such as Meta Quest) while discussing with other remote analysts online (see Figure 5D), through the collaborative functionalities offered by the ATON framework. This offers novel ways to visualize, inspect and discuss data records and interaction patterns together with remote experts in the same virtual space, using standard web browsers. Figure 5: **(A)** Loading of sample 3D KDE computed from users’ camera locations; **(B)** 6 DoF inspection of KDE data via immersive VR device; **(C)** AR inspection of user session through smartphone device; **(D)** collaborative inspection together with another remote analyst of the same record through mixed reality (Meta Quest passthrough). Bottom row: adding persistent bookmarks for analysts’ observation of specific moments and records. It is useful during analysts' reasoning and sense-making related to data records and/or aggregates to keep track of the process directly in the virtual 3D space. In order to provide such a functionality and maintain a consistent process with other remote analysts in the same collaborative session, Merkhet exploits a few core ATON routines. The web app model of the framework in fact offers, through the API ([[https://aton.ispc.cnr.it/apidoc/client/App.html](https://aton.ispc.cnr.it/apidoc/client/App.html)]([https://aton.ispc.cnr.it/apidoc/client/App.html](https://aton.ispc.cnr.it/apidoc/client/App.html)), accessed on 22 April 2024), the possibility to access dedicated, basic app storage (maintained on server side). Such a feature allows us to store generic data associated with the app, like custom data structures including add/update/delete operations, using the JSON patch approach (see [24], Section 3.5). We exploit such routines to store per-record or per-aggregate 3D annotations (bookmarks) made by analysts; this can be used by them to annotate specific moments (e.g., session records) with generic observations (see Figure 5, bottom row). In our pipeline, we investigated standard text content and audio content (vocal annotations), the latter being particularly useful for immersive or mixed reality sessions. For session records, bookmarks are linked to specific temporal marks, with corresponding attributes (view direction, location, etc.). Once the annotation is accessed by the analyst, the original captured viewpoint of the participant can be recalled (e.g., to discuss or focus on specific details/areas from the same perspective, etc.). The tool also provides voxel-based routines and classes to locally compute basic data aggregates alternatively to those generated by the hub (see previous section).