Traditionally, designers have used models to represent abstract design ideas or to analyse and evaluate the refined design solutions. The digital model, in particular, represents the logics, process, and intended result of the design in the form of digital information and media. Innovations in Internet of Things (IoT) and smart technologies now enable the various levels of real-world spatial interactions that were possible only when the user becomes an avatar in a cyberspace. This levels of interaction are virtualized for the design and the building itself by real-time interaction between digital and analogue model. This is the notion of smart space design. Smart space is defined as a kind of machine which is an assembly of sensors, actuators, and processors. This nature calls for a new design process model based on prototyping paradigm rather than traditional form-making process. Smart Analog Model is proposed to provide the real-world interaction with the functions and behaviours of the smart space being designed. Such a design process can be better supported by the symbiotic interaction between Digital Model (DM) and Smart Analog Model (SAM). The structure of the smart space is analysed and the role of BIM is discussed in the framework of the symbiotic design process. An exemplary design case of a kinetic facade is conducted to examine the usability of the proposed process model.