Smart built environments (SBE) include fundamentally different and enhanced capabilities compared to the traditional built environments. Traditional built environments consist of basic building elements and plain physical objects. These objects offer primitive interactions, basic use cases and direct affordances. As a result, the traditional architectural process is completely focused on two dimensions of design, i.e., the physical environment based on context and functional requirements based on the users. Whereas, SBEs have a third dimension, computational and communication capabilities embedded with physical objects enabling enhanced affordance and multi-modal interaction with the surrounding environment. As a result of the added capability, there is a significant change in activity pattern/spatial use pattern in an SBE. So, the traditional architectural design process needs to be modified to meet the unique requirements of SBE design. The aim of this thesis is to modify the traditional architectural design process by introducing SBE requirements. Secondly, this thesis explores a reference implementation of immersive technology based SBE design framework. The traditional architectural design tools are not always enough to represent, visualize or model the vast amount of data and digital components of SBE. SBE empowered with IoT needs a combination of the virtual and real world to assist in the design, evaluation and interaction process. A detailed discussion explored the required capabilities for facilitating an MR-based SBE design approach. An immersive technology is particularly helpful for SBE design because SBEs offer novel interaction scenarios and complex affordance which can be tested using immersive techniques.