In a small observational study in two Canadian architectural firms, the authors tracked the interactions (person-to-person, person with non-human sources such as documents) that took place during specific parts of the design process. This pilot study helped us to secure a grant which is currently allowing us to investigate the relationship between designing (in schools of architecture and architectural practice) and semiotic activity (processes of representation and communication). In one firm the development of a preliminary elevation design for a proposed corporate laboratory facility was followed over three continuous days to the point at which it was ready to be presented at an internal team meeting. Some months later, a senior designer, in frequent interaction with other members of the firm, spent a day preparing a Powerpoint presentation in which the elevation would be presented and justified to a committee of the client organisation. We recorded the day's transactions–the main subject of our paper--with fieldnotes, audio recording and the collection of documents. In making the transition from being a concept that circulated amongst the designers to one for external presentation, the design remained unchanged. However–and this is the point of the paper–the invisible ‘semiotic envelope' within which it had its meaning and was readable in a certain way had to undergo radical and arduous reconstruction. The design process had been as much a matter of the collaborative building of an ‘envelope' of relevance criteria, intentions, values and associations as of the conceptual configuration of materials in space. It was in reference to this envelope that the design had a clear logic and meaning for the designers. But, unlike the drawings, sketches and models, the semiotic envelope could not be directly transmitted to the client participants, who would bring their own envelope of expectations and meanings to the meeting. Specific rhetorical strategies had to be devised, therefore, to ensure that the design would be ‘read' correctly. This involved, for instance, a sort of fictional retrospective reconstruction of the design process in terms of choices between alternatives most of which were never actually entertained, and the conjuring up of ‘bad', ‘rejected' solutions for the sake of presenting the design as a desirable solution. It also involved the post-hoc identification of passages from the client's brief which could be cited as if they had directly governed the design process: ‘Look, we're simply following your requirements here.' The construction of a new justificatory envelope was partly informed by knowledge of the values, assumptions and perspectives (Aristotle's pathos) that framed the client committee's perceptions, as revealed at a previous meeting. In the paper we will briefly summarise our findings about the ‘semiotic envelope' that evolved during the earlier design stage, and then deal more fully with the preparation of the presentation, particularly as it addressed issues of glazing and massing. We will draw on transcripts of our audio-recordings and on the slides and other artefacts produced during the day.