Based in Falkirk, Scotland, Ferrier Crawford will now trade under the 3D banner, while FC boss Gordon Ferrier will become a divisional director of the company.
FC is crucial to 3D boss Charles Graham-Marr's plan to cultivate more clients in the hospitality sector.
Graham-Marr said: 'Having built a strong reputation in the UK and European hospitality sector with clients such as Malmaison, De Vere and Radisson Hotels, Gordon Ferrier felt that the resources of a large national practice would add considerable benefit for his existing and future clients.
'The acquisition further broadens the extensive experience and expertise of 3D Architects and creates a strong platform for significant growth of the practice's activity in the hospitality sector.'
Established in 1989, 3D Architects recently added London and Manchester offices to its Edinburgh and Glasgow-based operation.
Current projects include 40 Princes Street, Edinburgh - a mixed-use scheme inside the city's World Heritage boundary.