<p>The issue of conservation and valorisation of Cultural Heritage involves today 20<sup>th</sup> century architectural archives, that come to us with their often considerable amount of materials, where the predominance of the design drawings arises. Interpretation, fruition and sharing of archival materials aimed to deepening the knowledge of contemporary masters and architectural movements address the works of many international scholars. In particular, using the continuous innovations of digital modelling tools, a field of this research is developing reconstruction and new interpretations of masters’ unbuilt projects. The rise of H-BIM for modelling architectural heritage, has been flanked by some experiments really aimed to represent unbuilt architectures.</p> <p>This is the case presented in this paper: the unbuilt project for the “Teatro Comunale” in Cagliari, designed by Carlo Mollino between 1964 and 1965. The building has been digitally modelled and the potentialities of BIM tools are today in phase of evaluation, also in light of the aim to create a collection of reconstructive models of Mollino’s projects, to be shared on-line. In particular, in this phase of the research, we are exploring the potentiality of BIM aimed to evidencing the reliability of reconstructive modelling based on different documentary sources.</p>