This article proposes an alternative to multistage design that would be rational in connection with the development of information modelling technology (BIM). The disadvantages of the generally accepted multi-stage design system are indicated. In particular, we talk about the errors that the proposed system will avoid, and how the work should go during one-step design. The BIM model development scheme is given. It is considered advisable to replace the classical stage of the sketch with an expanded sketch design and the process of interaction of designers with expertise is considered. © 2023 Author(s).