While CAD systems have been immensely beneficial they require specialist knowledge and expertise for their operation, particularly where advanced modelling, simulation and analysis (virtual prototyping) is to be used. This requirement, combined with their dependence upon 2D digital interaction limits user engagement, constrains design process activities and restricts design performance. This includes the nature and level of collaboration and co-creation within design teams, with users and wider stakeholders; the accessibility of virtual prototyping tools including rapid prototyping; and the efficacy of the design (team) when undertaking tasks, such as ideation, design development, evaluation and DfX activities. To overcome these restrictions, the concept of a Lego-inspired tangible interface for CAD, virtual prototyping (VP) and rapid prototyping (RP) is to be investigated. The corresponding research programme comprises two interrelated research streams. The first addresses the technical and HCI challenges associated with the creation of real-time physical-to-digital model integration and user-in-the-loop digital-to-physical model integration. Both of these topics offer significant future research opportunities in their own right. The second research stream concerns investigation of the affordances, complementarity (with VP tools) and limitations of a Lego-inspired tangible interface for improving collaboration/co-creation, design performance and accessibility to VP and RP. Given the exploratory nature of the research three engineering domains will be considered: industrial design (assistive technology), special purpose machinery and construction.

An orchestration of physical and digital models of varying fidelities, and in differing sequences, is required for the product development process. The choice of these models depends upon the: skills of the design team; resources and tools available; purpose of the model; and nature of the design task. In all engineering disciplines a combination of digital and physical models is necessary to support the progression of the design process, with each model and iteration thereof generating new understanding and knowledge to inform decision-making. While extensive modelling - both physical and digital - is imperative to develop right-first-time products, the parallel use of digital and physical models gives rise to two interrelated issues. These are: the lack of revision control for physical prototypes; and the need for designers to manually inspect, measure, and interpret modifications to either digital or physical models, for subsequent update of the other. This manual process of revision control for physical models and what is referred to herein as 'twinning of digital-physical models' impacts on the cost, quality and time of the design and development process. In particular, the lack of revision control leads to multiple near-identical model instances, which contribute to issues of process management, traceability, decision-making, design duplication and inefficiency, and design rationale capture. It also makes optimisation of the product development process in terms of the digital-physical tool-chain all but impossible. In this project we will fundamentally redefine the revision control and twinning processes for digital and physical models from a manual, cumbersome, error-prone and expensive procedure to one that is seamlessly integrated (digital-to-physical and physical-to-digital), rapid, reliable and knowledge rich.