12. Visualization facilities

The visualization model described in the legacy guide (Visualization Facilities) — graphical representation services, converters producing “drawables”, GUI services — was implemented on top of the Open Scientist suite (OpenInventor, …). Open Scientist has long been retired and with it the corresponding Gaudi interfaces: Gaudi itself does not provide visualization facilities any more, and the converter-for-graphics approach has not been revived in the framework.

Experiment visualization today happens outside of the framework, reading framework output data:

• Phoenix is the experiment visualization tool of the HSF, used by LHCb, ATLAS and others. It reads event data from files rather than interfacing in-process with the framework: there is currently no direct interface between Phoenix and Gaudi — events are produced by a Gaudi job, persisted (see Accessing data), then opened in Phoenix or converted with helper scripts provided by the experiments.

• the interactive route for inspection remains Scripting and interactivity: GaudiPython lets one browse the transient stores and inspect event data at the Python prompt, which covers most “quick look at the event” needs.

If an experiment wants to expose event displays, the recommended direction is to persist an event model to a backend Phoenix supports, not to re-introduce in-process graphics converters in Gaudi.