Alongside bringing about new ways to make products, additive manufacturing (commonly referred to as 3d printing) opens up new ways to design them. This article explores a speculative model and vision between HCI and Industrial design, where the use of modular and modifiable ‘CAD’ parts coupled with intelligent systems could be used within lay user/retail settings to enable non-designers to create custom functional objects, with limit prior knowledge. Leading to design outputs that can be fabricated by on-site and on-demand additive manufacturing technologies. This article reports on a design workshop where cycling enthusiasts, supported by industrial designers, utilised, configured and modified a range of ‘CAD parts’ to create custom-made functional objects for additive manufacture. The study findings indicate the practicalities and challenges of implementing an ‘HCI system’ for the production of novel functional objects by novice designers, and signposts further investigation