The present study explores the relationship between the new frontiers of architectural survey and architectural restoration. The result is a project for the reassembly of the Altar of the Holy Heart of Mary in the Cathedral of Gerace, in the province of Reggio Calabria. It was dismantled in the last century with the purpose to restore the “solemn and sober aspect” of the church during the medieval age. The idea was born in the sphere of a multidisciplinary didactic experience, which involved history, conservation, digital modelling, design and enhancement of cultural heritage. The process, from analyses to project, followed four steps: realization of a systematic photogrammetrical survey of each architectural element of the 18th century altars of the cathedral, which were dismantled in the last century, with high precision photomodelling techniques; early identification of the single objects, positioning structured QR-CODE with metadata and short description directly in the shooting phase; pre-cataloguing phase, implemented by the compilation of single cards regarding each piece, using a redrafted version of the ICCD OA card (artwork 3.00 version); a proposal for the reassembly of the altar of the Holy Heart of Mary. The reassembly is conceived as an alternative to the reconstruction of the altar “as it was”, using a steel structure that is partially visible, which was studied to support and “exhibit” the marble pieces. The availability of numerical models for each piece facilitated, on one side, weight distribution analysis and, consequently, correct dimensioning of the support structure and, on the other side, interactive simulation processes for design optimisation and <i>aesthetic</i> evaluation.