The creation of 3-D CAD models is one of the key steps in the fusion reactor design cycle, and is very much a recurring process. A common division of labour sees engineers, draughtspeople, and analysts iterate ideas, requirements and constraints, 3-D CAD model(s), and analyses, respectively, to iteratively converge upon a working design. Whilst this traditional approach may work well during detailed design (e.g. for ITER), we contend that it is sub-optimal during the conceptual design, due to the large overheads associated with dealing with relatively mercurial geometries, load cases, and boundary conditions. In this work, we demonstrate that the automatic generation of 3-D CAD models for conceptual DEMO-class tokamak reactors is possible. The models, which comprise all major components ranging from the in-vessel components to the concrete radiation shield, are automatically produced for a given design point in approximately 30 seconds. This represents a significant acceleration of the traditional manual 3-D CAD model generation process for a typical reactor concept (∼1 month). The CAD data are generated within a reactor design framework and can be used for a range of purposes. We highlight the use case for neutronics, by demonstrating that a simplified 3-D 360◦ global neutronics model can be automatically built from the ground up and run, using faceted geometry and smeared material properties, all in under 1 hour.